vvEPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/600/R-95/131
August 1995
Methods for the
Determination of
Organic Compounds in
Drinking Water
Supplement
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EPA-600/R-95/131
AUGUST 1995
METHODS FOR THE DETERMINATION
OF ORGANIC COMPOUNDS
IN DRINKING WATER
SUPPLEMENT III
ERRATA
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
Printed on Recycled Paper
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DISCLAIMER
This manual has been reviewed by the National Exposure Research
constitute endorsement or recommendation for use.
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ERRATA
Methods for the Determination of Organic Compounds in Drinking Water
Supplement III, EPA/600-R-95/131
-------
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iRRATA - Nov. 27, L995
There is an error in the sample size in Section 8.1. This sheet corrects that
mges 515.2-11 and 515.2-12 and replace them with this sheet. corrects that
they are certified by the manufacturer or by an
independent source.
7.17.2 Transfer the stock standard solutions .into 15-ml
TFE-fluorocarbon-sealed screw cap amber vials. Store at
4°C or less when not in use.
7.17.3 Stock standard solutions should be replaced after 2 months
or sooner if comparison with laboratory fortified blanks
or QC samples indicate a problem.
7.17.4 Primary Dilution Standards — Prepare two sets of
standards according to the sets labeled A and B in Table
1. For each set, add approximately 25 ml of methanol to a
50 ml volumetric flask. Add aliquots of each stock
standard in the range of approximately 20 to 400 uL and
dilute to volume with methanol. Individual analyte
concentrations will then be in the range of 0.4 to 8 ug/mL
(for a 1.0 mg/mL stock). The minimum concentration would
be appropriate for an analyte with strong electron capture
detector (ECD) response, e.g. pentachlorophenol. The
maximum concentration is for an analyte with weak
response, e.g., 2,4-DB. The concentrations given in Table
2 reflect the relative volumes of stock standards used for
the primary dilution standards used in generating the
method validation data. Use these relative values to
determine the aliquot volumes of individual stock stan-
dards above.
7.18 INTERNAL STANDARD SOLUTION - Prepare a stock internal standard
solution by accurately weighing approximately 0.050 g of pure DBOB
Dissolve the DBOB in methanol and dilute to volume in a 10-mL
volumetric flask. Transfer the DBOB solution to a TFE-fluorocarbon-
sealed screw cap bottle and store at room temperature. Prepare a
primary dilution standard at approximately 1.00 /ig/mL by the addi-
i°?nnf ?° 2L*uf tne^ock standard to 100 mL of methanol. Addition
of 100 nL of the primary dilution standard solution to the final 5
mL of sample extract (Sect. 11) results 1n a final internal standard
concentration of 0.020 pg/ml. Solution should be replaced when
ongoing QC (Sect. 9) Indicates a problem. Note that DBOB has been
shown to be an effective Internal standard for the method analytes,
but other compounds may be used if the QC requirements in Sect 9
are met.
7.19 SURROGATE ANALYTE SOLUTION - Prepare a surrogate analyte stock
standard solution by accurately weighing approximately 0.050 g of
pure DCAA. Dissolve the DCAA in methanol and dilute to volume in a
10-mL volumetric flask. Transfer the surrogate analyte solution to
a TFE-fluorocarbon-sealed screw cap bottle and store at room temper-
ature. Prepare a primary dilution standard at approximately 2.0
Mg/mL by addition of 40 pL at the stock standard to 100 mL of
methanol. Addition of 250 /tL of the surrogate analyte solution to a
250-mL sample prior to extraction results 1n a surrogate concentra-
515.2-11
Rev. 1.1, Aug. 1995
-------
tion in the sample of 2 /tg/L and, assuming quantitative recovery of
DCAA, a surrogate analyte concentration in the final 5 ml extract of
0.1 /ig/mL. The surrogate standard solution should be replaced when
ongoing QC (Sect. 9) indicates a problem. DCAA has been shown to be
an effective surrogate standard for the method analytes, but other
compounds may be used if the QC requirements in Sect. 9 are met.
7.20 INSTRUMENT PERFORMANCE CHECK SOLUTION — Prepare a diluted dinoseb
solution by adding 10 /iL of the 1.0 fig/pi dinoseb stock solution to
the MTBE and diluting to volume in a 10-mL volumetric flask. To
prepare the check solution, add 40 ^L of the diluted dinoseb solu-
tion, 16 nl of the 4-nitrophenol stock solution, 6 0L of the 3,5-
dichlorobenzoic acid stock solution, 50 (il of the surrogate standard
solution, 25 pi of the internal standard solution, and 250 pi of
methanol to a 5-mL volumetric flask and dilute to volume with MTBE.
Methylate sample as described in Sect. 11.4. Dilute the sample to
10 ml in MTBE. Transfer to a TFE-fluorocarbon-sealed screw cap
bottle and store at room temperature. Solution should be replaced
when ongoing QC (Sect. 9) indicates a problem.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 Grab samples should be collected in 250 ml amber glass containers.
Conventional sampling practices (7) should be followed; however, the
bottle must not be prerinsed with sample before collection.
8.2 SAMPLE PRESERVATION ANQ STORAGE
8.2.1 If residual chlorine Is present, add 80 mg of sodium thiosul-
fate (or 50 mg of sodium sulfite) per liter of sample to the
sample bottle prior to collecting the sample. Demonstration
data in Section 17 of this method was obtained using sodium
thiosulfate. .r.-_
8.2.2 After the sample is collected in.the bottle containing the
dechlorinating agent, seal the bottle and mix to dissolve the
thiosulfate. , . ...
/*.- ' '
8.2.3 Add hydrochloric add (diluted 1:1 in reagent water) to the
sample at the sampling site in amounts to produce a sample pH
£ 2. Short range (0-3) pH paper (Sect. 6.14) may be used to
monitor the pH. Note: Do not attempt to mix sodium thiosul-
fate and HC1 in the sample bottle prior to sample collection.
8.2.4 The samples must be iced or refrigerated at 4"C away from
light from the time of collection until extraction. Preser-
vation study results Indicate that the sample analytes (mea-
sured as total add), except 5-hydroxy-dicamba, are stable in
water for 14 days when stored under these conditions (Tables
8 and 9). The concentration of 5-hydroxydicamba is seriously
degraded over 14 days in a biologically active matrix. How-
ever, analyte stability win very likely be affected by the
515.2-12
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*
ERRATA; Nov. 27, 1995
7.19) to each 250-mL- sample. The surrogate will be at a
concentration of 2 ng/l. Dissolve 50 g sodium sulfate in the
sample. . ,. , ; ..... t>;
11.1.3 Add 4 ml of 6 N NaOH to each sample, seal, and shake. Check
the pH of the sample with pH paper or a pH meter; if the
sample does not have a pH greater than or equal to 12, adjust
the pH by adding more 6 N NaOH. Let the sample sit at room
temperature for 1 hr, shaking the separatory funnel and
contents periodically. Note: Since many of the herbicides
contained in this method are applied as a variety of esters
and salts, it is vital to hydrolyze them to the parent acid
prior to extraction. This step must be included in the
ana^ls of a11 extracted field samples, LRBs, LFBs, LFMs
and QCS. '
11.1.4 Use 15 mL mmethylene chloride to rinse the sample bottle and
the granduated cylinder. Then transfer the methylene
chloride to the separatory funnel and extract the sample bv
vigorously shaking the funnel for 2 min with periodic ventinq
to release excess pressure. Allow the organic layer to sepa-
rate from the water phase for a minimum of 10 min. If the
emulsion interface between layers is more than one-third the
volume of the solvent layer, the analyst must employ
mechanical techniques to complete the phase separation The
. optimum technique depends upon the sample, put may include
stirring, filtration through glass wool, centrifugation, or
other Physical methods. Discard the methylene chloride phase
(Sect. 14, 15).
11.1.5 Add a second 15-ml volume of methylene chloride to the separ-
atory funnel and repeat the extraction procedure a second
time, discarding the methylene chloride layer. Perform a
third extraction in the same manner.
11.1.6 Drain the contents of the. separatory funnel into a 500-mL
beaker. Adjust the pH to 1.0 ± 0.1 by the dropwise addition
of concentrated sulfuric acid with constant stirring. Monitor
the pH with a pH meter (Sect. 6.8) or short range (0-3) oH
paper (Sect. 6.14). ' v
11.2 SAMPLE EXTRACTION
11.2.1 Vacuum Manifold — Assemble a manifold (Sect. 6.3) consistinq
°f H*3?"11111 f1asks Wlth f^ter funnels (Sect. 6.1,6.2).
Individual vacuum control, on-off and vacuum release valves
and vacuum gauges are desirable. Place the 47 mm extraction
disks (Sect. 7.1) on the filter frits.
11.2.2 Add 20 mL of 10% by volume of methanol In MTBE to the top of
each disk without vacuum and allow the solvent to remain for
2 min. Turn on full vacuum and draw the solvent through the
disks, followed by room air for 5 min.
515.2-19
Rev. 1.1, August 1995
-------
11.2.3 Adjust the vacuum to approximately 5 in. (mercury) and add
the following in series to the filter funnel (a) 20 ml
methanol (b) 20 ml reagent water (c) sample. Do not allow
the disk to dry between steps and maintain the vacuum at 5
in.
11.2.4 After all the sample has passed through the disk, apply
maximum vacuum and draw room air through the disks for 20
min.
11.2.5 Place the culture tubes (Sect. 6.4) in the vacuum tubes to
collect the eluates. Elute the disks with two each 2-mL
aliquots of 10% methanol in MTBE. Allow each aliquot to
remain on the disk for one min before applying vacuum.
11.2.6 Rinse each 500-mL beaker (Sect. 11. 1.6) with 4 ml of pure MTBE
and elute the disk with this solvent as in Sect. 11.2.5.
11.2.7 Remove the culture tubes and cap.
11.3 EXTRACT PREPARATION
11.3.1 Pre-rinse the drying tubes (Sect. 7.5.1) with 2 ml of MTBE.
11.3.2 Remove the entire extract with a 5-mL pipet and drain the
lower aqueous layer back Into the culture tube. Add the
organic layer to the sodium sulfate drying tube (Sect.
7.5.1). Maintain liquid 1n the drying tube between this and
subsequent steps. Collect. the dried extract in a 15-mL
graduated centrifuge tube or a 10-mL Kuderna-Danish tube.
11.3.3 Rinse the culture tube with an additional 1 mL of MTBE and
repeat Sect. 11.3.2. •-.-
11.3.4 Repeat step Sect. 11.3.3 and finally add a 1-mL aliquot of
MTBE to the drying tube before it empties. The final volume.
should be 6-9 ml. In this form the extract is esterified as
described
11.4 EXTRACT ESTERIFICATION WITH DIAZOMETHANE ~ See Section 11.5 for
alternative procedure.
11.4.1 Assemble the dlazomethane generator (Figure 1) in a hood.
11.4.2 Add 5 ml of ethyl ether to Tube 1. Add 4 ml of Oiazald
solution (Sect. 7.12) and 3 ml of 37X KOH solution (Sect.
7.16.1) to the reaction tube 2. Immediately place the exit
tube Into the collection tube containing the sample extract.
Apply nitrogen flow (10 mL/m1n) to bubble dlazo-methane
through the extract. Each charge of the generator should be
sufficient to ester ify four samples. The appearance of a
persistent yellow color 1s an Indication that esterifi cat ion
1s complete. The first sample should require 30 sec to 1 min
515.2-20
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- Nov. 27,1995 """'•"'' .......
here is an equation missing in Sect. 10.4.3. This sheet corrects that error Remove
24.2*21 and 524. -22 and replace them with this sheet.
10.3.4 Determine that the absolute areas of the quantitation ions of
the internal standard and .surrogates have not decreased by
more than 30% from the areas measured in the most recent
continuing calibration check, or by more than 50% from the
areas measured during initial calibration. If these areas
have decreased by more than these amounts, adjustments must
be made to restore system sensitivity. These adjustments may
require cleaning of the MS ion source, or other maintenance
as indicated in Sect. 10.3.6, and recalibration. Control
charts are useful aids in documenting system sensitivity
changes. J
10.3.5 Calculate the RF for each analyte of concern and surrogate
compound from the data measured in the continuing calibration
check. The RF for each analyte and surrogate must be within
30% of the mean value measured in the initial calibration.
Alternatively, if a linear or second order regression is
used, the concentration measured using the calibration curve
must be within 30% of the true value of the concentration in
the calibration solution. If these conditions do not exist
remedial action must be taken which may require recalibrati-
on. All data from field samples obtained after the last
successful calibration check standard, should be considered
suspect. After remedial action has been taken, duplicate
samples should be analyzed if they are available.
10.3.6 Some possible remedial actions. Major maintenance such as
cleaning an ion source, cleaning quadrupole rods, etc re-
quire returning to the initial calibration step.
10.3.6.1 Check and adjust,.GC and/or MS operating conditions-
check the MS resolution, and calibrate the mass
scale.
10.3.6.2 Clean 'or replace, the splitless injection liner;
sllaftl-ze a new injection liner. This applies only
if the Injection liner is an integral part of the
system.
10.3.6.3 Flush the GC column with solvent according to manu-
facturer's instructions.
10.3.6.4 Break off a short portion (about 1 meter) of the
column from the end near the injector; or replace GC
column. This action will cause a slight change in
retention times. Analyst may need to redefine
retention windows.
10.3.6.5 Prepare fresh CAL solutions, and repeat the initial
calibration step.
10.3.6.6 Clean the MS ion source and rods (if a quadrupole).
524.2-21
Rev. 4.1, August 1995
-------
10.3.6.7 Replace any components that allow analytes to come
into contact with hot metal surfaces.
10.3.6.8 Replace the MS electron multiplier, or any other
faulty components.
10.3.6.9 Replace the trap, especially when only a few com-
pounds fail the criteria in Sect. 10.3.5 while the
majority are determined successfully. Also check
for gas leaks in the purge and trap unit as well as
the rest of the analytical system.
10.4 Optional calibration for vinyl chloride using a certified gaseous
mixture of vinyl chloride in nitrogen can be accomplished by the
following steps.
10.4.1 Fill the purging device with 25.0 ml (or 5-mL) of reagent
water or aqueous calibration standard.
10.4.2 Start to purge the aqueous mixture. Inject a known volume
(between 100 and 2000 fil) of the calibration gas (at room
temperature) directly into the purging, device with a gas
tight syringe. Slowly inject the gaseous sample through a
septum seal at the top of the purging device at 2000 ^L/min.
If the injection of the standard is made through the aqueous
sample inlet port, flush the dead volume with several ml of
room air or carrier gas. Inject the gaseous standard before
5 min of the 11-min purge time have elapsed.
10.4.3 Determine'the aqueous equivalent concentration of vinyl
chloride standard, 1n /wj/L, injected with one of the
following equations:
5 ml samples, S
25 ml samples, S
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ERRATA: November 27, 1995
There is an error in the revision number. This sheet corrects that error
Remove pages 525.2-1 and 525.2-2; and replace them with this shee;:.
METHOD 525.2 DETERMINATION OF ORGANIC COMPOUNDS IN DRINKING WATER
BY LIQUID-SOLID-EXTRACTION AND CAPILLARY COLUMN GAS
CHROMATOGRAPHY/MASS SPECTROMETRY
Revision 2.0
IF , •
•sit'. .
J.W. Elchelberger, T.D. Behymer, H.L. Budde - Method 525.
Revision 1.0, 2.0, 2.1 (1988)
J.H. Elchelberger, T.D; Behymer, and H.L. Budde -. Method 525 1
Revision 2.2 (July 1991)
J.W. Elchelberger, J.W. Munch^ and J.A. Shoemaker
Method 525.2 Revision 1.0 (February, 1994)
J.W. Munch - Method 525.2, Revision 2.0 (1995)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH*AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
,
(•*%!_*•
525.2-1 ~7
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METHOD 525.2
DETERMINATION OF ORGANIC COMPOUNDS IN DRINKING WATER
BY LIQUID-SOLID EXTRACTION AND CAPILLARY COLUMN '
GAS CHROMATOGRAPHY/MASS SPECTROMETRY
1. SCOPE AND APPLICATION
1.1 This is a general purpose method that provides procedures for
determination of organic compounds in finished drinking water,
sourbe water, or drinking water in any treatment stage. The
method is applicable to a wide range of organic compounds that are
efficiently partitioned from the water sample onto a C18 organic
phase chemically bonded to a solid matrix in a disk or cartridge,
and sufficiently volatile and thermally stable for gas chromatog-
raphy. Single-laboratory accuracy and precision data have been
determined with two instrument systems using both disks and car-
tridges for most of the following compounds:
Analvte
Acenaphthylene
Alachlor
Aldrin
Ametryn
Anthracene
Atraton
Atrazine
Benz[a]anthracene
Benzo[b;
Benzo[k;
BenzoJX
f 1 uoranthene
fluoranthene
pyrene
Benzo[g,h,i]perylene
Bromacil
Butachlor
Butyl ate
Butylbenzylphthalate
Carboxin
Chlordane components
Al pha-chlordane
Gamma-chlordane
Trans nonachlor
Chlorneb
Chiorobenzilate
Chlorpropham
Chlorothalonil
Chlorpyrifos
2-Chlorobiphenyl
152
269
362
227
178
211
215-
228
252
252
.252
276
260
311
217
312
235
406
406
440
206
324
213
264
349
188
Chemical Abstracts Service
Registry Number
208-
15972-
309-
834-
120-
1610-
1912-
56-
205-
207-
50-
191-
314-
23184-
2008-
85-
5234-
5103-
5103-
39765-
2675-
510-
101-
1897-
2921-
2051-
96-8
60-8
00-2
12-8
12-7
17-9
24-9
55-3
82-3
08-9
32-8
24-2
40-9
66-9
41-5
68-7
68-4
71-9
74-2
80-5
77-6
15-6
21-3
45-6
88-2
60-7
525.2-2
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ERRATA - Nov. 27, 1995
There is an error in the analyte list. This sheet corrects that error. Remove pages
551.1-3 and 551.1.-4 and replace them with this sheet.
Hexachlorocyclopentadiene 77.47-4
Lindane (gamma-BHC) 58-89-9
'-Jejtolachlor . :;,s ; 51218-45-2
Metribuzin ""~" 21087-64-9
Methoxychlor 72-43-5
Simazine 122-34-9
Trifluralin 1582-09-8
1.2 This analyte list includes twelve commonly observed chlorination
disinfection byproducts (3,4), eight commonly used chlorinated
organic solvents and sixteen halogenated pesticides and herbicides.
1.3 This method is intended as a stand-alone procedure for either the
analysis of only the trihalomethanes (THMs) or for all the
chlorination disinfection, by-products (DBFs) with the chlorinated
organic solvents or as a procedure for the total analyte list The
dechlorination/preseryation technique presented in section 8 details
two different dechlorinating agents. Results for the THMs and the
eight solvents may be obtained from the analysis of samples
employing either dechlorinating agent. (Sect. 8.1.2)
1.4 After an analyte has been identified "and quantitated in an unknown
sample with the primary GC column (Sect. 6.9.2.1) qualitative
confirmation of results is strongly recommended by gas
chromatography/mass spectrometry (GC/MS) (10,11), or by GC analysis
using a dissimilar column (Sect. 6.9.2.2). ;
1.5 The experimentally determined method detection limits (MDLs) (121
. for the above listed analytes are provided in Tables 2 and 8
Actual MDL values will vary according to the particular matrix
analyzed and the specific instrumentation employed.
1.6 This method is restricted to use by or under the supervision of
analysts experienced in the use of GC .and in the interpretation of
gas chromatograms. Each analyst must demonstrate the ability to
generate acceptable results with.this method using the procedure
described in Sect. at1*.
1.7 Methyl-t-butyl ether (MTBE) is recommended as the primary extraction
solvent in this method since it effectively extracts all of the
target analytes listed In Sect. 1.1. However, due to safety
concerns associated with MTBE and the current use of pentane by some
laboratories for certain method analytes, pentane is offered as an
optional extraction solvent for all analytes except chloral hydrate.
If project requirements specify the analysis of chloral hydrate,
MTBE must be used as the extracting solvent. This method includes
sections specific for pentane as an optional solvent.
2. SUMMARY OF METHOD
2.1 A 50 ml sample aliquot is extracted with 3 mL of MTBE or 5 ml of
pentane. Two jA. of the extract 1s then injected into a GC equipped
551.1-3
"- Rev. 1.0, August 1995
-------
with a fused silica capillary column and linearized electron capture
detector for separation and analysis. Procedural standard
calibration is used to quantitate method analytes.
2.2 A typical sample can be extracted and analyzed by this method in 50
min for the chlorination by-products/chlorinated solvents and 2 hrs.
for the total analyte list. Confirmation of the eluted compounds
may be obtained using a dissimilar column (6.9.2.2) or by the use of
GC-MS. Simultaneous confirmation can be performed using dual
primary/confirmation columns installed in a single injection port
(Sect. 6.9.3) or a separate confirmation analysis.
3. DEFINITIONS
3.1 INTERNAL STANDARD (IS)'— A pure analyte(s) added to a sample,
extract, or standard solution in known amount(s) and used to measure
the relative responses of other method analytes and surrogates that
are components of the same sample or solution. The internal
standard must be an analyte that is not a sample component.
3.2 SURROGATE ANALYTE (SA) — A pure analyte(s), which is extremely
unlikely to be found in any sample, and which is added directly to a
sample aliquot in known amount(s) before extraction or other
processing and is measured with the same procedures used to measure
other sample components. The purpose of a surrogate analyte is to
monitor method performance with each sample.
3.3 LABORATORY DUPLICATES (LD1 and LD2) -- Two sample aliquots, taken in
the laboratory from a single sample bottle, and analyzed separately
with identical procedures. Analyses of LD1 and LD2 indicate
precision associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures. This method
cannot utilize laboratory duplicates since sample extraction must
occur in the sample vial and sample transfer is not possible due to
analyte volatility.
3.4 FIELD DUPLICATES (FD1 and FD2) -.-.Two separate samples collected at
the same time and plate under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as well as with
laboratory procedures. Since laboratory duplicates cannot be
analyzed, the collection and analysis of field duplicates for this
method is critical.
3.5 LABORATORY REAGENT BLANK (LRB) — An aliquot of reagent water, or
other blank matrix, that 1s treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents, internal
standards, and surrogates that are used with other samples. The LRB
is used to determine if method analytes or other interferences are
present in the laboratory environment, the reagents, or the
apparatus.
551.1-4
-------
ERRATA - Nov. 27, iyy5 .--,-•-y. „>-•
There are several errors in Section 7.1.7.1 and 7.1.7.4. This sheet corrects those errors
Remove pages 551.1-11 and 551.1-12 and replace them with this sheet.
temperature to 400°C and hold for 30 min.--Store in a capped
glass bottle not in a plastic container.
7.1.7 Sample Preservation Reagents
7.1.7.1 Phosphate buffer - Used to lower the sample matrix
pH to 4.8-5.5 in order to inhibit base catalyzed
degradation of the haloacetonitriles (7), some of
the chlorinated solvents, and to standardize the pH
of all samples. Prepare a dry homogeneous mixture
of 1% Sodium Phosphate, dibasic (Na2HP04)/99%
Potassium Phosphate, monobasic (KH2P04) by weight
(example: 2 g Na2HP04 and 198 g KH2P04 to yield a
total weight of 200 g) Both of these buffer salts
should be in granular form and of ACS grade or
better. Powder would be ideal but would require
extended cleanup time as outlined below in Sect.
7.1.7.5 to allow for buffer/solvent settling.
7.1.7.2 Arnmprfium Chloride, NH4C1, ACS Reagent Grade. Used
to convert free chlorine to monochloramine.
Although this is not the traditional dechlorination
mechanism, ammonium chloride is categorized as a
dechlprinating" agent in this method.
7.1.7.3 Sodfum Sulfite, Na2S03, ACS Reagent Grade. Used as
a dechlorinating agent for chloral hydrate sample
analysis.
7.1.7.4 To ||mplify the addition of 6 mg of the
dechlorinating agent to the 60 ml vial, the
• ... . dechlorinating salt is combined with the phosphate
buffer as a homogeneous mixture. Add 1.2 g of the
appropriate dechlorinating agent to 200 g of the
phosphate buffer. When 1 g of the buffer/
decWForinating agent mixture are added to the 60-mL
sairiple vial, 6 mg of the dechlorinating agent are
included reflecting an actual concentration of 100
mg/L. Two separate mixtures are prepared, one
containing ammonium chloride and the other with
sodium sulfite.
7.1.7.5 If background contaminants are detected in the salts
listed in Sections 7.1.7.1 through 7.1.7.3, a
solvent rinse cleanup procedure may be required.
Ttifse contaminants may coelute with some of the high
mpl,ecular weight herbicides and pesticides. These
salts cannot be muffled since they decompose when
heated to 400°C. This solvent rinsing procedure is
applied to the homogeneous mixture prepared in Sect.
7*1.7.4.
•HI
|i| "" 551.1-11
'i-iSlv
-\± •$.*'
0f- Rev. 1.0, August 1995
-------
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FOREWORD
Environmental measurements are required to determine the quality of
ambient waters and the character of waste effluents. The National Exposure
Research Laboratory - Cincinnati (NERL-Cincinnati) conducts research to:
o Develop and evaluate analytical methods to identify and measure the
concentration of chemical pollutants in drinking waters, surface
waters, groundwaters, wastewaters, sediments, sludges, and solid
wastes.
o Investigate methods _for the identification and measurement of viruses,
bacteria and other microbiological organisms in aqueous samples and to
determine the responses of aquatic organisms to water quality.
o Develop and operate a quality assurance program to support the
achievement of data quality objectives in measurements of pollutants
in drinking water, surface water, groundwater, wastewater, sediment
and solid waste. •
o Develop methods and models to detect and quantify response in aquatic
and terrestrial organisms exposed to environmental stressors and to
correlate the exposure with effects on chemical and biological
indicators. ;i|;
This publication, "Determination of Organic Compounds in Drinking Water
Supplement III," was prepared to gather together under a single cover a set of
15 new or improved laboratory analytical methods for organics compounds in
drinking water. NERL-Cincinnati is pleased to provide this manual and believe
that it will be of considerable value to many public and private laboratories
that wish to determine organic compounds in drinking water for regulatory or
other reasons. *;•-
Alfred P. Dufour, Acting Director
Aquatic Research Division
National Exposure Research
Laboratory - Cincinnati
m
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ABSTRACT
Fifteen analytical methods for organic compounds in drinking water are
documented in detail. Most of these methods were published as prior versions
in other methods manuals in this series. The versions in Supplement III
provide corrections, minor technical enhancements, and editorial improvements
to the previously published analytical methods. Several previously distrib-
uted but not formally published methods are also included. Fourteen of the
fifteen methods utilize high resolution gas chromatography (GC) for separation
of analytes from each other and from other substances in the water sample.
One method employs high performance reverse phase liquid chromatography for
the separation. Two methods utilize a mass spectrometer for the unambiguous
identification and measurement of the compounds separated by high resolution
GC. These two methods are extremely versatile and have been single-laboratory
validated for a total of 194 individual compounds and 8 commercial product
mixtures. Most methods have also been multi-laboratory validated although not
all possible analytes have been included in these studies. Essentially all of
the major chlorine disinfection by-products that have been identified in
drinking water are included in the methods in this manual.
iv
-------
TABLE OF CONTENTS
Method i
Number Title Revision Page
Foreward . • / ........ 1 .. ill
Abstract . . • iv
Acknowledgment ..... vii
Analyte - Method Cross Reference .' viii
Introduction ... •......'. 1
502.2 Volatile Organic Compounds in Water by Purge 2.1
and Trap Capillary Column Gas Chromatography !
*<
with Photoionfzation and Electrolytic
Conductivity Detectors in Series
I1';
504.1 1,2-Dibromoethfne (EDB), l,2-Dibromo-3-Chloro- 1.1
propane (DBCP)^ and 1,2,3-Trichloropropane i
(123TCP) in Wa%r by Microextraction and Gas !
Chromatography |; ' •
505 Analysis of Orga-hohal ide Pesticides and 2.1
Commercial Polychlorinated Biphenyl (PCB)
Products in Water by Microextraction and Gas
Chromatography u
506 determination of Phthalate and Adi pate Esters 1.1
in Drinking Water by Liquid-Liquid Extraction
or Liquid-Solid Extraction and Gas
Chromatography with Photoionization Detection
507 Determination of Nitrogen- and Phosphorus- 2.1
Containing Pesticides in Water by Gas
Chromatography with a Nitrogen-Phosphorus Detector
508 Determination of Chlorinated Pesticides in Water 3.1
by Gas Chromatography with an Electron Capture
Detector
508.1 Determination of Chlorinated Pesticides, 2.0
Herbicides, and Organohalides by Liquid-Solid
Extraction and Electron Capture Gas Chromatography
509 Determination of Ethylene Thiburea (ETU) in 1.1
Water using Gas Chromatography with a
Nitrogen-Phosphorus Detector
-------
TABLE OF CONTENTS (Continued)
Method
Number
515.1
515.2
524.2
525.2
531.1
551.1
552.2
Title
Determination of Chlorinated Acids' in Water by Gas
Chromatography with an Electron Capture Detector
Determination ,of Chlorinated Acids in Water
using Liquid-Solid Extraction and Gas
Chromatography with an Electron Capture Detector
Measurement of Purgeable Organic Compounds in
Water by Capillary Column Gas Chromatography/Mass
Spectrometry
Determination of Organic Compounds in Drinking
Water by Liquid-Solid Extraction and Capillary
Column Gas Chromatography/Mass Spectrometry
Measurement of N-Methylcarbamoyloximes and
N-Methylcarbamates in Water by Direct Aqueous
Injection HPLC with Post Column Derivatization
Determination of Chlorination Disinfection
Byproducts, Chlorinated Solvents, and Halogenated
Pesticides/Herbicides in Drinking Water by
Liquid-Liquid Extraction and Gas Chromatography
with Electron-Capture Detection
Revision
4.1
Page
in
Determination of HaToacetic Ac:ds and Dalapon
Drinking Water by Liquid-Liquid Extraction,
Derivatization and Gas Chromatography with Electron
Capture Detection
1.1
4.1
2.0
3.1
1.0
1.0
VI
-------
ACKNOWLEDGMENT
The many, past and present researchers and authors who contributed to the
current status of the methods in supplement III are recognized oh the title
pages of the 15 methods in Supplement III. ! Jean W. Munch deserves special
recognition for Supplement III because she critically read every method and
incorporated numerous corrections, technical enhancements, and editorial
improvements into each of them. Thomas 0. Behymer acquired the precision and
accuracy data for the Aroclors in Method 525.2, proof read the next-to-last
drafts of all the methods, and provided numerous additional corrections.
Special thanks is due to Diane Schirmann who processed many of the final
corrections, placed all 15 methods and the introductory material in the
standard format, and prepared the camera-ready copies for printing. The
authors would like to thank the many others who reviewed previous and current
versions of these methods and provided comments, suggestions and corrections.
VII
-------
ANALYTE - METHOD CROSS REFERENCE
ANALYTE
Acenaphthylene
Acetone
Acifluorfen
Acrylonitrile
Alachlor
Aldicarb
Aldicarb sulfone
Aldicarb sulfoxide
Aldrin
Ally! chloride
Ametryn
Anthracene
Atraton
Atrazine
Baygon
Bentazon
Benzene
Benz[a]anthracene
Benzo[b]fluoranthene
Benzo[k]fluoranthene
Benzo[a]pyrene
Benzo[g,h,i]perylene
Bis (2-ethylhexyl) phthalate
Bis (2-ethylhexyl) adipate
Bromobenzene
Bromacil
Bromochloroacetic acid
Bromochloroacetoni tri1e
Bromochloromethane
Bromodichloroacetic acid
Bromodi chloromethane
Bromoform
Bromomethane
Butachlor
2-Butanone
Butyl ate
Butyl benzylphthalate
n-Butylbenzene
sec-Butyl benzene
tert-Butylbenzene
Carbaryl
Carboxin
Carbofuran
Carbon disulfide
Carbon tetrachloride
Chloramben
Chloral Hydrate
Chlordane
METHOD NO.
515.1,
505, 507, 508.1, 525.2,
505, 508, 508.1,
507,
507,
505, 507, 508.1, 525.2,
515.1,
502.2,
502.2,
507, 525.2,
502.2, 524.2,
507,
506,
502.2,
502.2,
502.2,
507,
502.2, 524.2,
525
524
515
524
551
531
531
531
525
524
525
525
525
551
531.1
515.2
524
525
525
525
525
525
506
506
502.2,
502.2, 524.2,
502.2,
507, 508.1, 525.2
524
551
552,
551.
551,
552.
524.
551.
524.
524.
525.
525.
524:2
524,
524.
531.
525.
531.
524.
551.
515.1
551.1
505, 508
vm
-------
ANALYTE
METHOD NO.
Alpha-chlordane
Gamma-chlordane
Trans nonachlor
Chloroacetqnitrile
Chloroberizene
Chiorobenzi late
2-Chlorobiphenyl
Chlorodibromoacetic acid
1-Chlorobutane
Chloroethane
Chloroform
Chloromethane
Chloroneb
Chloropicrin
Chlorothalonil
2-Chlorotoluene
4-Chlorotoluene
Chlorpropham
Chlorpyrifos
Chrysene
Cyanazine
Cycloate
Dacthal(DCPA)
2,4-D
Dalapon
2,4-DB
DCPA acid metabolites
4,4'-DDD
4,4'-DDE
4,4'-DDT
Diazinon
Dibenz[a,h]anthracene
Dibromoacetic acid
Dibromoacetonitri1e
Dibromochloromethane
1,2-Di bromo-3-chloropropane
1,2-Dibromoethane
Dibromomethane
Dicamba
Dichloroacetic acid
DiChloroacetonitrile
1,2-Dichlorobenzene
1,3-Dichlorobenzene
1,4-Dichlorobenzene
3,5-Dichlorobenzoic acid
trans-l,4-Dichloro-2-butene
1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethene
cis-1,2-Dichloroethene
505, 508,
505, 508,
508,
502.2,
508,
508,
508.1,
515.1,
508,
508,
508,
508,
502.2,
502.2, 504.1,
502.2, 504.1,
508.1, 525.2
508.1, 525.2
525.2
524.2
502.2, 524.2
508.1, 525.2
525.2
552.2
524.2
502.2, 524.2
524.2, 551.1
502.2, 524.2
508.1, 525.2
551.1
508.1, 525.2
502.2, 524.2
502.2, 524.2
507, 525.2
525.2
525.2
525.2, 551.1
507, 525.2
525.2
515.1, 515.2
515.2, 552.2
515.1, 515.2
508.1, 515.1
508.1, 525.2
508.1, 525.2
508.1, 525.2
507, 525.2
525.2
552.2
551.1
524.2, 551.1
524.2, 551.1
524.2, 551.1
502.2, 524.2
515.1, 515.2
552.2
551.1
502.2, 524.2
502.2, 524.2
502.2, 524.2
515.1, 515.2
524.2
502.2, 524.2
502.2, 524.2
502,2, 524.2
502.2, 524.2
IX
-------
ANALYTE
METHOD NO.
trans-1,2-Di chloroethene
Di chlorodi f1uoromethane
1,2-Di chloropropane
1,3-Di chloropropane
2,2-Dichloropropane
1,1-Di chloropropene
1,1-Di chloropropanone
ci s-1,3-Di chloropropene
trans-1,3-Di chloropropene
1,1-Di chloro-2-propanone
Dichloroprop
Di-n-butyl phthalate
Di-n-octyl phthalate
2,3-Dichlorobiphenyl
Dichlorvos
Dieldrin
Diethyl ether
Diethyl phthalate
Di(2-ethylhexyl)adi pate
Di(2-ethylhexyl)phthalate
Dimethyl phthalate
2,4-Dinitrotoluene
2,6-Dinitrotoluene
Dinoseb
Diphenamid
Disulfoton
Disulfoton sulfone
Disulfoton sulfoxide
Endosulfan I
Endosulfan II
Endosulfan sulfate
Endrin
Endrin aldehyde
Endrin ketone
EPTC
Ethoprop
Ethyl benzene
Ethyl methacrylate
Ethylene thiourea
Etridiazole
Fenamiphos
Fenarimol
Fluorene
Fluridone
Heptachlor
Heptachlor Epoxide
2,2',3,3',4,4',6-Heptachloro-
biphenyl
Hexachlorobenzene
Hexachlorobutadiene
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
502.2, 524.2
524.2
502.2,524.2
502.2, 524.2
551.1
515.1, 515.2
506, 525.2
506
525! 2
507, 525.2
505, 508, 508.1, 525.2
524.2
506, 525.2
525.2
525.2
506, 525.2
525.2
525.2
515.1, 515.2
507, 525.2
507, 525.2
507, 525.2
507, 525.2
508, 508.1, 525.2
508, 508.1, 525.2
508, 508.1, 525.2
505, 508, 508.1, 525.2, 551.1
508, 508.1, 525.2, 551.1
551.1
507, 525.2
507, 525.2
502.2, 524,2
524.2
509
508, 508.1, 525.2
507, 525.2
507, 525.2
525.2
507, 525.2
505, 508, 508.1, 525.2, 551.1
505, 508, 508.1, 525.2, 551.1
525.2
505, 508, 508.1, 525.2, 551.1
502.2, 524.2
-------
ANALYTE
METHOD NO.
Hexachlorocyclopentadi ene
2,2',4,4',5,6'-Hexachloro-
biphenyl
Hexachlorocyclohexane, alpha
Hexachlorocyclohexane, beta
Hexachlorocyclohexane, delta
Hexachlorocyclopentadiene
Hexachloroethane
2-Hexanone
Hexazinone
HCH-alpha
HCH-beta
HCH-delta
HCH-gamma (lindane)
3-Hydroxycarbofuran
5-Hydroxydicamba
Indeno[l,2,3,c,d]pyrene
Isophorone
Isopropylbenzene
4-Isopropyltoluene
Lindane (gamma-BHC)
Merphos
Methacrylonitrile
Methiocarb
Methomyl
Methoxychlor
Methylacrylate
Methylene chloride
Methyl iodide
Methylmethacrylate
Methyl paraoxon
4-Methyl-2-pentanone
Methyl-t-butyl-ether
Metolachlor
Metribuzin
Mevinphos
MGK 264
Molinate
Monobromoacetic acid
Monochloroacetic acid
Naphthalene
Napropamide
Nitrobenzene
4-Nitrophenol
2-Nitropropane
cis-Nonachlor
Norflurazon
2,2',3,3',4,5',6,6'-Octa-
chlorobiphenyl
505, 508.1, 551.1
525.2
507,
508,
508,
508,
508,
515.1,
502.2,
505, 525.2,
507,
505, 508, 508.1, 525.2,
502.2,
507,
507, 508.1, 525.2,
507, 508.1, 525.2,
507,
507,
507,
502.2,
507,
507,
525.2
525.2
525.2
525.2
524.2
524.2
525.2
508.1
508.1
508.1
508.1
531.1
515.2
525.2
525.2
524.2
524.2
551.1
525.2
524.2
531.1
531.1
551.1
524. -2
524.2
524.2
524.2
525.2
524.2
524.2
551.1
551.1
525.2
525.2
525.2
552.2
552.2
524.2
525.2
524.2
515.1
524.2
505
525.2
525.2
XI
-------
ANALYTE
METHOD NO.
Oxamyl
Pebulate
2,2',3',4,6-Pentachloro-
biphenyl
Pentachloroethane
Pentachlorophenol
cis-Permethrin
Trans-Permethrin
Phenanthrene
Picloram
Prometon
Prometryn
Pronamide
Propachlor
Propazine
Propionitrile
Propylbenzene
n-Propylbenzene
Pyrene
Simazine
Simetryn
Stirofos
Styrene
2,4,5-T
2,4,5-TP
Tebuthiuron
Terbacil
Terbufos
Terbutryn
2,2',4,4'-Tetrachlorobiphenyl
1,1,1,2-Tetrachloroethane
1,1,2,2-Tetrachloroethane
Tetrachloroethene
Tetrachloroethylene
Tetrahydrofuran
Toluene
Toxaphene
Triademefon
Tribromoacetic acid
Trichloroacetic acid
Trichloroacetonitrile
1,2,3-Tri chlorobenzene
1,2,4-Trichlorobenzene
1,1,1-Trichloroethane
1,1,2-Tri chloroethane
Trichloroethene
Trichloroethylene
Tri chlorof1uoromethane
1,1,1-Tri chloro-2-propanone
1,2,3-Tri chloropropane
531.1
507, 525.2
515.1, 515.2,
508, 508.1,
508, 508.1,
515.1,
507,
507,
507,
508, 508.1,
507,
505, 507, 508.1,
507,
507,
502.2,
515.1,
515.1,
507,
507,
507,
507,
502.2,
502.2,
502.2,
502.2,
505, 508, 508.1,
507,
505.2,
505.2,
502.2, 524.2,
502.2, 524.2,
505.2,
502.2,
504.1, 524.2, 551.1
525.2
524.2
525
525
525
525
515
525
525
525
525
525
524
502
524
525
525
525
525
524
515
515.2
525.2
525.2
525
525
525
524
524
524
551
524
524
525
525
552
552
551
524
524
551
551
524
551
524
551
xn
-------
ANALYTE METHOD NO.
2,4,5-Trichlorobiphenyl 502.2, 525.2
Tricyclazole 507, 525.2
Trifluralin 508, 508.1, 525.2, 551.1
1,2,4-Trimethylbenzene 502.2, 524.2
1,3,5-Trimethylbenzene 502.2, 524.2
Vernolate 507, 525.2
Vinyl chloride 502.2, 524.2
0-Xylene 505.2, 524.2
m-Xylene • 502.2, 524.2
p-Xylene 502.2, 524.2
Aroclor 1016 505, 508, 508.1, 525.2
Aroclor 1221 505, 508, 508.1, 525.2
Aroclor 1232 505, 508, 508.1, 525.2
Aroclor 1242 505, 508, 508.1, 525.2
•Aroclor 1248 505, 508, ,508.1, 525.2
Aroclor 1254 505, 508, 508.1, 525.2
Aroclor 1260 505, 508, 508.1, 525.2
xm
-------
-------
INTRODUCTION
William L. Budde and Jean W. Munch
The purpose of this third supplement to "Methods for the Determination of
Organic Compounds in Drinking Water" is to provide corrections, minor tech-
nical enhancements, and editorial improvements to some previously published
analytical methods and to document several significantly enhanced or pre-
viously unpublished methods. Some of these modifications were described in
"Technical Notes on Drinking Water Methods", EPA/600/R-94/173, October, 1994
and these method changes have been incorporated into the body of the methods
in this supplement. All methods in this supplement are written'in a format
specified by the United States Environmental Protection Agency's Environmental
Monitoring Management Council.
As in other manuals in this series,, each of the methods in Supplement III
was intended to stand alone, that is, each method may be removed from the
manual, photocopied, inserted into another binder, and used without loss of
information. The stand-alone character of the methods comes at some cost of
duplication of material, but the authors believe that the added bulk of the
methods is a small price to pay for the flexibility of the format.
All the methods in supplement III have been given new dates and version
numbers or slightly modified method numbers to distinguish them from pre-
viously published versions. A change in the revision number indicates a
relatively small modification to the method and a change in the method number
usually indicates a relatively larger change in the method. The cover page of
each method gives the title, method number, revision, and date, and also lists
the previous versions, previous authors, and dates if they are known. The
purpose of this very brief method history is to assist users who may have
older versions in their files in understanding the chronological relationship
of methods as technical improvements were made over the years. It also gives
due credit to previous authors who contributed to the development of the
methods in this and previous manuals in this series. Unless otherwise
indicated, all authors were direct Federal employees of the U. S.
Environmental Protection Agency at the time of their contributions.
Some methods in supplement III utilize the liquid-solid extraction
technology which was pioneered by the USEPA in the original Method 525 in
1988. The scientifically correct term liquid-solid extraction (LSE), in which
both phases of the equilibrium partition process are named, is used throughout
the manual in place of the misleading commercial term "solid phase
extraction". Colloquial lab terms such as "clean-up" and "spike" are replaced
by "sample preparation" or "interference separation" and "fortified"
respectively.
While the title of supplement III, and previous manuals in this series,
specifies drinking water, these methods will very likely be applicable to
other aqueous matrices including surface water, ground water, beverages, and
1
-------
waste water. However since some methods have been tested with only reagent
water and/or drinking water, caution is needed when applying these methods to
matrices other than reagent or drinking water. One exception is Method 524.2
which has been tested in a large multi-laboratory validation study with a
variety of aqueous matrices.
During 1992 the USEPA and the American Society for Testing and Materials
(ASTM) Committee D-19 on Water jointly conducted a multi-laboratory study of
an ASTM version of Method 524.2, revision 3.0 using 68 of the volatile organic
compound analytes. Over 40 volunteer laboratories participated in the study to
characterize the performance of Method 524.2 in terms of accuracy, precision,
and detection limits. Analyses were conducted using fortified reagent water,
drinking water, ground water, several industrial waste waters, and a simulated
hazardous waste site aqueous leachate. Fortified analyte concentrations ranged
from 0.2 /ig/L to 80 /jg/L and generally excellent accuracy and precision was
reported. Full details of that study will be published by the ASTM.
The methods in supplement III are listed below along with a comment for
each that gives the previous version of the method, the citation and date of
publication of the previous version, and the highlights of the changes in the
version in supplement III.
Method in SUDP. Ill
502.2 rev. 2.1
Comments
Rev. 2.0 was published in EPA/600/4-88/039 in Dec.
1988 and July 1991. Rev. 2.1 is modified to specify
conditions under which alternative trapping materials
may be used and instructions are clarified for sample
preservation and dechlorination. Conditions which do
not require a photoic.,ization detector are specified.
504.1 rev. 1.1
505
rev. 2.1
506
rev. 1.1
Method 504.1 improves Method 504 rev. 2.0 which was
published in EPA/600/4-88/039 in Dec. 1988 and July
1991. In 504.1 changes are made to the sampling
procedures, the holding time, and the compound 1,2,3-
trichloropropane is added to the analyte list.
Cautions are included on the frequent coelution of
ethylene dibromide and bromodichloromethane.
Rev. 2.0 was published in EPA/600/4-88/039 in Dec.
1988 and July 1991. Rev. 2.1 is modified to remove
alternative detectors except mass spectrometry for
qualitative confirmation and to provide additional
instructions on the measurement of multi-component
mixtures.
Rev. 1.0 was published in EPA/600/4-90/020 (Supp. I)
in July, 1990. Rev. 1.1 is modified to correct
errors in the method summary.
-------
507 rev. 2.1
508 rev. 3.1
508.1 rev. 2.0
509 rev. 1.1
515.1 rev. 4.1
515.2 rev. 1.1
524.2 rev. 4.1
525.2 rev. 2.0
Rev. 2.0 was published in EPA/600/4-88/039 in Dec.
1988 and July 1991. Rev. 2.1 is modified to remove
mercuric chloride as a preservative. Data tab\es are
reorganized for clarity and addition of method
detection limits. Alternative detectors are
eliminated except mass spectrometry for qualitative
confirmation.
Rev 3.0 was published in EPA/600/4-88/039 in Dec.
1988 and July 1991. Rev. 3.1 is modified to remove
mercuric chloride as a preservative. Data tables are
reorganized for clarity and addition of method
detection limits. Alternative detectors are
eliminated except mass spectrometry for qualitative
confirmation.
Method 508.1 is a significant improvement to Method
508. It employs the liquid-solid extraction
technology of Method 525.2 and has an analyte list
consisting of many Method 507 and Method 508
substances including the former commercial Aroclor
mixtures.
Method 509 is a single analyte method for the
pesticide metabolite ethylenethiourea. This method
is derived from national pesticide survey Method 6.
.Rev. 4.0 was published in EPA/600/4-88/039 in Dec.
1988 and July 1991. Rev. 4.1 is modified to remove
mercuric chloride as a preservative. Data tables are
reorganized for clarity and addition of method
detection limits. Trimethylsilyldiazomethane (TMSD)
is added as an alternative methylating agent.
Rev. 1.0 was published in EPA/600/R-92/129 (Supp. II)
in August, 1992. Rev. 1.1 is modified to include
trimethylsilyldiazomethane (TMSD) as an alternative
methylating agent.
Rev. 4.0 was published in EPA/600/R-92/129 (Supp. II)
in August, 1992. Rev. 4.1 is modified to specify
conditions under which alternative trapping materials
may be used and instructions are clarified for sample
preservation and dechlorination. The quality
assurance section is clarified and data for two
analytes are added.
Method 525.2, rev. 2.0 is an improvement to Method
525.1, rev. 2.2 which was published in EPA/600/4-
88/039 in July, 1991. Method 525.2 includes criteria
for judging the equivalency of alternative liquid-
solid extraction cartridges and disks. The elution
-------
531.1 rev. 3.1
551.1 rev. 1.0
552.2 rev. 1.0
solvent is modified and data are included for
additional analytes including all former commercial
Aroclor mixtures.
Rev. 3.0 was published in EPA/600/4-88/039 in Dec.
1988 and July 1991. Rev. 3.1 is modified to remove
the requirement to freeze the samples. Data tables
are revised for clarity and method detection limits
are included.
Method 551.1 is an improvement to Method 551 which
was published in EPA/600/4-90/020 (Supp. I) in July
1990. Pentane is included as an alternative solvent
for some analytes, the analyte list is expanded, and
a new sample preservation technique is used.
Method 552.2 is similar to Method 552 which was
published in EPA/600/4-90/020 (Supp. I) in July,
1990. Method 552.2 uses acidic methanol for
methylation instead of diazomethane and expands the
analyte list.
-------
METHOD 502.2
VOLATILE ORGANIC COMPOUNDS IN WATER BY PURGE AND TRAP
CAPILLARY COLUMN GAS CHROMATOGRAPHY WITH PHOTOIONIZATION
AND ELECTROLYTIC CONDUCTIVITY DETECTORS IN SERIES
Revision 2.1
Edited by J.W. Munch (1995)
R.W. Slater, Jr. and J.S. Ho - Method 502.2, Revision 1.0 (1986)
J.S. Ho - Method 502.2, Revision 2.0 (1989)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
502.2-1
-------
METHOD 502.2
VOLATILE ORGANIC COMPOUNDS IN WATER BY PURGE AND TRAP
CAPILLARY COLUMN GAS CHROMATOGRAPHY WITH PHOTOIONIZATION
AND ELECTROLYTIC CONDUCTIVITY DETECTORS IN SERIES
1. SCOPE AND APPLICATION
1.1 This is a general purpose method for the identification and
simultaneous measurement of purgeable volatile organic compounds in
finished drinking water, raw source water, or drinking water in any
treatment stage (1-3). The method is applicable to a wide range of
organic compounds, including the four trihalomethane disinfection
by-products, that have sufficiently high volatility and low water
solubility to be efficiently removed from water samples with purge
and trap procedures. The following compounds can be determined by
this method.
Analvte
Benzene
Bromobenzene
Bromochloromethane
Bromodi chloromethane
Bromoform
Bromomethane
n-Butylbenzene
sec-Butyl benzene
tert-Butylbenzene
Carbon tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
2-Chlorotoluene
'4-Chlorotoluene
Di bromochloromethane
1,2-Di bromo-3-chloropropane
1,2-Dibromoethane
Dibromomethane
1,2-Di chlorobenzene
1,3-Di chlorobenzene
1,4-Di chlorobenzene
Dichlorodif1uoromethane
1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethene
cis-1,2-Dichloroethene
trans-1,2-Di chloroethene
1,2-Di chloropropane
Chemical Abstract Services
Registry Number
71-43-2
108^86-1
74-97-5
75-27-4
75-25-2
74-83-9
104-51-8
135-98-8
98-06-6
56-23-5
108-90-7
75-00-3
67-66-3
74-87-3
95-49-8
106-43-4
124-48-1
96-12-8
106-93-4
74-95-3
95-50-1
541-73-1
106-46-7
75-71-8
75-34-3
107-06-2
75-35-4
156-59-4
156-60-5
78-87-5
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1,3-Dichlpropropane 142-28-9
2,2-Dichloropropane. 590-20-7
1,1-Dichloropropene 563-58-6
cis-l,3-Dichloropropene 10061-01-5
trans-1,3-Dichloropropene 10061-02-6
Ethylbenzene 100-41-4
Hexachlorobutadiene 87-68-3
Isopropylbenzene- 98-82-8
4-Isopropyltoluene 99-87-6
Methylene chloride 75-09-2
Naphthalene 91-20-3
Propylbenzene 103-65-1
Styrene 100-42-5
1,1,1,2-Tetrachloroethane 630-20-6
1,1,2,2-Tetrachloroethane 79-34-5
Tetrachloroethene 127-18-4
Toluene , 108-88-3
; 1,2,3-Trichlorobenzene . 87-61-6
1,2,4-Trichlorobenzene 120-82-1
1,1,1-Trichloroethane 71-55-6
1,1,2-Trichloroethane 79-00-5
Trichloroethene 79-01-6
Trichlorofluoromethane 75-69-4
1,2,3-Trichloropropane 96-18-4
1,2,4-Trimethyl benzene 95-63-6
1,3,5-Trimethylbenzene 108-67-8
Vinyl chloride 75-01-4
o-Xylene 95-47-6
m-Xylene 108-38-3
p-Xylene 106-42-3
1.2 This method is applicable to the determination of total
trihalomethanes, and other volatile organic compounds (VOCs). Method
detection limits (MDLs) (4) are compound and instrument dependent
and vary from approximately 0.01-3.0 fig/I. The applicable
concentration range of this method is also compound and instrument
dependent and is approximately 0.02 to 200 //g/L. Analytes that are
inefficiently purged from water will not be detected when present at
low concentrations, but they can be measured with acceptable
accuracy and precision when present in sufficient amounts.
1.3 Two of the three isomeric xylenes may not be resolved on the
capillary column, and if not, must be reported as isomeric pairs.
2. SUMMARY OF METHOD
2.1 Highly volatile organic compounds with low water solubility are
extracted (purged) from the sample matrix by bubbling an inert gas
through a 5 ml aqueous sample. Purged sample components are trapped
in a tube containing suitable sorbent materials. When purging is
complete, the sorbent tube is heated and backflushed with helium to
thermally desorb trapped sample components onto a capillary gas
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chromatography (GC) column. The column is temperature programmed to
separate the method analytes which are then detected with a
photoionization detector (PID) and an electrolytic conductivity
detector (ELCD) placed in series. Analytes are-quantitated by.
procedural standard calibration (Sect.3.14).
2.2 Identifications are made by comparison of_the retention times of
unknown peaks to the retention times of standards analyzed under the
same conditions used for samples. Additional confirmatory
information can be gained by comparing the relative response from
the two detectors. For absolute confirmation, a gas chromatography/
mass spectrometry (GC/MS) determination according to USEPA Method
524.2 is recommended.
2.3 This method requires the use of a PID to measure target analytes
that cannot be measured with an electrolytic conductivity detector.
If only halogenated analytes,.such as the trihaldmethanes are to be
measured, a PID is not needed.
3. DEFINITIONS
3.1 INTERNAL STANDARD — A pure analyte(s) added to a solution in known
' amount(s) and used to measure the relative responses of other method
analytes and surrogates that are components of the same solution.
The internal standard must be an analyte that is not a sample.
component.
3.2 SURROGATE ANALYTE — A pure analyte(s), which is,extremely unlikely
to be found in any sample, and which is added to a sample aliquot in
known amount(s) before extraction and is measured with the same
procedures used to measure other sample components. The purpose of
a surrogate analyte is to monitor method performance with each
sample.
3.3
3.4
3.5
LABORATORY DUPLICATES (LD1 and LD2) — Two sample aliquots taken in
the analytical laboratory and analyzed separately with identical
procedures. Analyses of LD1 and LD2 give a measure of the precision
associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures.
FIELD DUPLICATES (FD1 and FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as w,ell as with
laboratory procedures.
LABORATORY REAGENT BLANK (LRB) -- An aliquot of reagent water that
is treated exactly as a sample including exposure to all glassware,
equipment, solvents, reagents, internal standards, and surrogates
that are used with other samples. The LRB is used to determine if
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method analytes or other interferences are present in the laboratory
environment, the reagents, or the apparatus.
3.6 FIELD REAGENT BLANK (FRB) — Reagent water placed in a sample
container in the laboratory and treated as a sample in all respects,
including exposure to sampling site conditions, storage,
preservation and all analytical procedures. The purpose of the FRB
is to determine if method analytes or other interferences are
present in the field environment.
3.7 LABORATORY PERFORMANCE CHECK SOLUTION (LPC) -- A solution of method
analytes, surrogate compounds, and internal standards used to
evaluate the performance of the instrument system with respect to a
defined set of method criteria.
3.8 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water to
which known quantities of the method analytes are added in the
•laboratory. The LFB is analyzed exactly like a sample, and its
purpose is to determine whether the methodology is in control, and
whether the laboratory is capable of making accurate and precise
measurements at the required method detection limit.
3.9 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
3.10 STOCK STANDARD SOLUTION — A concentrated solution containing a
single certified standard that is a method analyte, or a
concentrated solution of a single analyte prepared in the laboratory
with an assayed reference compound. Stock standard solutions are
used to prepare primary dilution standards.
3.11 PRIMARY DILUTION STANDARD SOLUTION — A solution of several analytes
prepared in the laboratory from stock standard solutions and diluted
as needed to prepare calibration solutions and other needed analyte
solutions.
3.. 12 CALIBRATION STANDARD (CAL) — A solution prepared from the primary
dilution standard solution and stock standard solutions of the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration.
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3.13 QUALITY CONTROL SAMPLE (QCS) — A sample matrix containing method
analytes or a solution of method analytes in a water miscible
solvent which is used to fortify reagent water or environmental
samples. The QCS is obtained from a source external to the
laboratory, and is used to check laboratory performance with
externally prepared test materials.
3.14 PROCEDURAL STANDARD CALIBRATION -- A calibration method where
aqueous calibration standards are prepared and processed (e.g.
purged,extracted, and/or derivatized) in exactly the same manner as
a sample. All steps in the process from addition of sampling
preservatives through instrumental analyses are .included in the
calibration. Using procedural standard calibration compensates for
any inefficiencies in the processing procedure.
4. INTERFERENCES
4.1 During analysis, major contaminant sources are volatile materials in
the laboratory and impurities in the inert purging gas and in the
sorbent trap. The use of non-polytetrafluoroethylene (PTFE) plastic
tubing, non-PTFE thread sealants, or flow controllers with rubber
components in the purging device should be avoided since such
materials out-gas organic compounds which will be concentrated in
the trap during the purge operation. Analyses of laboratory reagent
blanks (Sect. 9.2) provide information about the presence of
contaminants. When potential interfering peaks are noted in
laboratory reagent blanks, the analyst should change the purge gas
source and regenerate the molecular sieve purge gas filter.
Subtracting blank values from sample results is not permitted.
4.£ Interfering contamination may occur when a sample containing low
concentrations of volatile organic compounds is analyzed immediately
after a sample containing relatively high concentrations of volatile
organic compounds. A preventive technique is between-sample rinsing
of the purging apparatus and sample syringes with two portions of
reagent water. After analysis of a sample containing high
concentrations of volatile organic compounds, one or more laboratory
reagent blanks should be analyzed to check for cross contamination.
4.3 Special precautions must be taken to analyze for methylene chloride.
The analytical and sample storage area should be isolated from all
atmospheric sources of methylene chloride, otherwise random
background levels will result. Since methylene chloride will
permeate through PTFE tubing, all gas chromatography carrier gas
lines and purge gas plumbing should be constructed from stainless
steel or copper tubing. Laboratory clothing worn by the analyst
should be clean since clothing previously exposed to methylene
chloride fumes during common liquid/liquid extraction procedures can
contribute to sample contamination.
4.4 When traps containing combinations of silica gel and coconut
charcoal are used, residual water from previous analyses collects in
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the trap and can be randomly released into the analytical column.
To minimize the possibility of this occurring, the trap is
reconditioned after each use as described in Sect. 11.4.
5. SAFETY
5.1 The toxicity or carcinogenicity of chemicals used in this method has
not been precisely defined; each chemical should be treated as a
potential health hazard, and exposure to these chemicals should be
minimized. Each laboratory is responsible for maintaining awareness
of OSHA regulations regarding safe handling of chemicals used in
this method. Additional references to laboratory safety are
available (5-7) for the information of the analyst.
5.2 The following method analytes have been tentatively classified as
known or.suspected human or mammalian carcinogens: benzene, carbon
tetrachloride, 1,4-dichlorobenzene, 1,2-dichlorethane,
hexachlorobutadiene, 1,1,2,2-tetrachloroethane,
1,1,2-trichloroethane, chloroform, 1,2-dibromoethane,
tetrachloroethene, trichloroethene, and vinyl chloride. Pure
standard materjals and stock standard solutions of these compounds
should be handled in a hood. A NIOSH/MESA approved toxic gas
respirator should be worn when the analyst handles high
concentrations of these toxic compounds.
6. EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.)
6.1 SAMPLE CONTAINERS - 40-mL to 120-mL screw cap vials each equipped
with a PTFE-faced silicone septum. Prior to use, wash vials and
septa with detergent and rinse with tap and distilled water. Allow
the vials and septa to air dry at room temperature, place in a 105°C
oven for one hour, then remove and allow to cool in an area known to
be free of organics.
6.2 PURGE AND TRAP SYSTEM - The purge and trap system consists of three
separate pieces of equipment:, purging device, trap, and desorber.
Systems are commercially available from several sources that meet
all of the following specifications.
6.2.1 The all glass purging device (Figure 1) must be designed to
accept 5-mL samples with a water column at least 5. cm deep.
Gaseous volumes above the sample must be kept to a minimum
(<15 mL) to eliminate dead volume effects. A glass frit
.should be installed at the base of the sample chamber so that
the purge gas passes through the water column as finely
divided bubbles with a diameter of.<3 mm at the origin.
Needle spargers may be used, however, the purge gas. must be
introduced at a point <5 mm from the base of the water
column.
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6.2.2 The trap (Figure 2) must be at least 25 cm long and have an
inside diameter of at least 0.105 in. Starting from the
inlet, the trap must contain the following amounts of
adsorbents: 1/3 of 2,6-diphenylene oxide polymer, 1/3 of
silica gel, and 1/3 of coconut charcoal. It is recommended
that 1.0 cm of methyl silicone coated packing be inserted-at
the inlet to extend the life of the trap. If it is not
necessary to analyze for dichlorodifluoromethane, the
charcoal can be eliminated and the polymer increased to fill
2/3 of the trap. If only compounds boiling above 35°C are to
be analyzed, both the silica gel and charcoal can be
eliminated and the polymer increased to fill the entire trap.
Before initial use, the trap should be conditioned overnight
at 180°C by backflushing with an inert gas flow of at least
20 mL/min. Vent the trap effluent to the room, not to the
analytical column. Prior to daily use, the trap should be
conditioned for 10 min at 180°C with backflushing. The trap
may be vented to the analytical column during daily
conditioning; however, the column must be run through the
temperature program prior to analysis of samples. The use of
alternative sorbents is acceptable provided the data acquired
meets all quality control criteria described in Section 9,
and provided the purge and desorption procedures specified in
Section 11 of the method are not changed. Specifically, the
purging time, the purge gas flow rate, and the desorption
time may not be changed. Since many of the potential
alternate sorbents may be thermally stable above 180°C,
alternate traps may be desorbed and baked out at higher
temperatures than those described in Section 11. If higher
temperatures are used, the analyst should monitor the data
for possible analyte and/or trap decomposition.
6.2.3 The use of the methyl silicone coated packing is recommended,
but not mandatory. The packing serves a dual purpose of
protecting the adsorbent from aerosols, and also of insuring
that the adsorbent is fully enclosed within the heated zone
of the trap thus eliminating potential cold spots.
Alternatively, silanized glass wool may be used as a spacer
at the trap inlet.
6.2.4 The desorber (Figure 2) must be capable of rapidly heating
the trap to 180°C. The polymer section of the trap described
in Sect.6.2.2 should not be heated higher than 200°C or the
life expectancy of the trap will decrease. Trap failure is
characterized by a pressure drop in excess of 3 pounds per
square inch across the trap during purging or by poor
bromoform sensitivities.
6.3 GAS CHROMATOGRAPHY SYSTEM
6.3.1 The GC must be capable of temperature programming and should
be equipped with variable-constant differential flow
502.2-8
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controllers so that the column flow rate will remain constant
throughout desorption and temperature program operation. The
column oven may need to' be cooled to <10°C (Sect. 6,3.3), and
therefore, a subambient oven coritroller may be required.
6.3.2 Capillary Gas Chromatography Columns. Any gas chromatography
column that meets the performance specifications of this
method may be used. Separations of the calibration mixture
must be equivalent or better than those described in this
method. If other GC columns or temperature programs are
used, or whenever these procedures are changed, the method
performance data in Sect. 9.3 must be repeated. Three useful
columns have been identified: column 1 (Sect. 6.3.3) and
column 2 (Sect. 6.3.4) both provide satisfied separations for
sixty organic compounds. Column 3 (Sect. 6.3.5), which has
been satisfactorily demonstrated for the GC/MS method 524.2,
may also be used.
6.3.3 Column 1- 60m long x 0.75mm'ID VOCOL (Supelco, Inc.)
wide-bore capillary column with 1.5 jim film thickness, or
equivalent. The flow rate of helium carrier gas is adjusted
to about 6 mL/min. The'column temperature is held for 8 min
at 10°C, .then programmed to1 180°C at 4°C/min, and held until
all expected compounds have eluted. A sample chromatogram
obtained with this column is presented in Figure 3.
Retention times that may be anticipated with this column are
listed in Table 1. Data obtained with this column is
presented in Sect. 13 and 17.
6.3.4 Column 2 - 105m long x 0.53mm ID, RTX-502.2 (O.T
Corporation/T.ESTEK Corporation) mega-bore capillary column,
with 3.0 im film thickness, or equivalent. The flow rate of
helium carrier gas is adjusted to about 8 mL/min. The column
temperature is held for 10 min at 35°C, then programmed to
200°'C at 4°C/min, and held until all expected compounds have
eluted. A sample chromatogram obtained with this column is
presented in Figure 4. Retention times that may be
anticipated with this column are listed in Table 3. Data
obtained with this column is presented in Sect. 13 and 17.
6.3.5 Column 3 - 30 m long x 0.53 mm ID D8-624 mega-bore (J&W
Scientific, Inc.) column with 3 p.m film thickness.
6.3.6 A series configuration of a high temperature photoionization
detector (PID) equipped with 10 eV (nominal) lamp and
electroconductivity detector (ELCD) is required. This allows
the simultaneous analysis of VOCs that are aromatic or
unsaturated by photoionization detector and organohalide by
an electrolytic conductivity detector.
6.3.7 A Tracor 703 photoionization detector and a Tracer Hall model
700-A detector connected in series' with a short piece of
502.2-9
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uncoated capillary tube, 0.32 mm ID was used to develop the
single laboratory method performance data described in
Sect.13. The system and operating conditions used to collect
these data are as follows:
Column:
The purge-and-trap Unit:
PID detector base temperature:
Reactor tube:
Reactor temperature:
Reactor base temperature:
Electrolyte:
Electrolyte flow rate:
Reaction gas:
Carrier gas plus make-up gas:
Column 1 (Sect.6.3.3)
Tekmar LSC-2
250°C
Nickel 1/16 in. OD
810°C
250°C
100% n-propyl alcohol
0.8 mL/min
Hydrogen at 40 mL/min
Helium at 30 mL/min
6.3.8 An O.I. Model 4430 photoionization detector mounting together
with the model 4420 electrolytic conductivity detector (ELCD)
as a dual detector set was used to develop the single
laboratory method performance data for column 2 described in
Sect. 13. The system and the operating conditions used to
collect these data are as follows:
Column:
The purge-and-trap unit:
Reactor tube:
Reactor temperature:
Reactor base temperature:
Electrolyte:
Electrolyte flow rate:
Reaction gas:
Carrier gas plus make-up gas:
Column 2 (Sect.6.3.4)
O.I. 4460A
Nickel 1/16 in. OD
& .02in.ID
950°C
250°C
100 % n-propyl alcohol
0.050 mL/min
Hydrogen at 100 mL/min
Helium at 30 mL/min
6.4 SYRINGE AND SYRINGE VALVES
6.4.1 Two 5-mL glass hypodermic syringes with Luer-Lok tip.
6.4.2 Three 2-way syringe valves with Luer ends.
6.4.3 One 25-/iL micro syringe with a 2 in x 0.006 in ID, 22° bevel
needle (Hamilton #702N or equivalent).
6.4.4 Micro syringes - 10, 100 /zL.
6.4.5 Syringes - 0.5, 1.0, and 5-mL, gas tight with shut-off valve.
6.5 MISCELLANEOUS
6.5.1 Standard solution storage containers - 15-mL bottles with
PTFE-lined screw caps.
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7. REAGENT AND STANDARDS
7.1 TRAP PACKING MATERIALS
7.1.1 2,6-Diphenylene oxide polymer, 60/80 mesh, chromatographic
grade (Tenax GC or equivalent).
7.1.2 Methyl silicone packing (optional) - OV-1 (3%) on
Chromosorb-W, 60/80 mesh or equivalent.
7.1.3 Silica gel - 35/60 mesh, Davison, grade 15 or equivalent.
7.1.4 Coconut charcoal - Prepare from Barnebey Cheney, CA-580-26
lot #M-2649 (or equivalent) by crushing through 26 mesh
screen.
7.2 REAGENTS
7.2.1 Ascorbic acid - ACS Reagent grade, granular.
7.2.2 Sodium thiosulfate - ACS Reagent grade, granular.
7.2.3 Hydrochloric acid (1+1) - Carefully add a measured volume of
cone. HC1 to equal volume of reagent water.
7.2.4 Reagent water - It should be demonstrated to be free of
interferences. Prepare reagent water by passing tap water
through a filter bed containing about 0.5 kg of activated
carbon, by using a water purification system, or by boiling
distilled water for 15 min followed by a 1-h purge with inert
gas while the water temperature is held at 90°C. Store in
clean, narrow-mouth bottles with PTFE-lined septa and screw
caps.
7.2.5 Methanol - demonstrated to be free of analytes.
7.2.6 Vinyl chloride - 99.9% pure vinyl chloride is available from
Ideal Gas Products, Inc., Edison, New Jersey and from
Matheson, East Rutherford, New Jersey. Certified mixtures of
vinyl chloride in nitrogen at 1.0 and 10.0 ppm (v/v) are
available from several sources.
7.3 STOCK STANDARD SOLUTIONS - These solutions may be purchased as
certified solutions or prepared from pure standard materials using
the following procedures:
7.3.1 Place about 9.8 mL of methanol into a 10-mL ground-glass
stoppered volumetric flask. Allow the flask to stand,
unstoppered, for about 10 min or until all alcohol-wetted
surfaces have dried. Weigh to the nearest 0.1 mg.
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7.3.2 If the analyte is a liquid at room temperature, use a 100-fj.l
syringe and immediately add two or more drops of reference
standard to the flask. Be sure that the reference standard
falls directly into the alcohol without contacting the neck
of the flask. If the analyte is a gas at room temperature,
fill a 5-mL valved gas-tight syringe with the standard to the
5.0-mL mark, lower the needle to 5 mm above the methanol
meniscus, and slowly inject the standard into the neck area
of the flask. The gas will rapidly dissolve in the methanol.
7.3.3 Reweigh, dilute to volume, stopper, then mix by inverting the
flask several times. Calculate the concentration in
micrograms per microliter from the net gain in weight. When
compound purity is certified at 96% or greater, the weight
can be used without correction to calculate the concentration
of the stock standard.
7.3.4 Store stock standard solutions in 15-mL bottles equipped with
PTFE-lined screw caps. Methanol solutions prepared from
liquid analytes are stable for at least four weeks when
stored at 4°C. Methanol solutions prepared from gaseous
analytes are not stable for more than one week when stored at
<0°C; at room temperature, they must be discarded after one
day. Storage time may be extended only if the analyte proves
their validity by analyzing quality control samples.
7.4 PRIMARY DILUTION STANDARD SOLUTION - Use stock standard solutions to
prepare primary dilution standard solutions that contain the
analytes in methanol. The primary dilution standards should be
prepay 'd at concentrations that can be easily diluted to pr epare
aqueous calibration standard solutions (Sect. 9.2) that will bracket
the working concentration range. Store the primary dilution
standard solutions with minimal headspace and check frequently for
signs of deterioration or evaporation, especially just before
preparing calibration standard solutions from them. Storage times
described for stock standard solutions in Sect. 7.3.4 also apply to
primary dilution standard solutions.
7.5 INTERNAL STANDARD SOLUTION - Prepare a fortified solution containing
l-chloro-2-fluorobenze or fluorobenzene and 2-bromo-l-chloropropane
in methanol using the procedures described in Sect. 7.3 and 7.4. It
is recommended that the primary dilution standard be prepared at a
concentration of 5 jug/mL of each internal standard compound. The
addition of 10 /zL of such a standard to 5.0 mL of sample or
calibration standard would be equivalent to 10 M9/L.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 SAMPLE COLLECTION AND DECHLORINATION
8.1.1 Collect all samples in duplicate. If samples,.such as
finished drinking water, are suspected to contain residual
502.2-12
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8.1.2
chlorine, add a dechlorinating agent the bottle. The
preferred dechlorinating agent is sodium thiosulfate, but
ascorbic acid may also be used. Add 3 mg of sodium
thiosulfate or 25 mg of ascorbic acid per 40 ml of sample to
the sample bottle before filling NOTE: If the residual
chlorine is likely to be present > 5 mg/L, a determination of
the amount of the chlorine may be necessary. Diethyl-p-
phenylenediamine (DPD) test kits are commercially available
to determine residual chlorine in the field. Add an addi-
tional 3 mg of sodium thiosulfate or 25 mg of ascorbic acid
per each 5 mg/L of residual chlorine.
When sampling from a water tap, open the tap and allow the
system to flush until the water temperature has stabilized
(usually about 10 min). • Adjust the flow to about 500 mL/min
and collect duplicate samples containing the desired dechlo-
rinating agent from the flowing stream.
8.1.3 When sampling from an open body of water, partially fill a
1-quart wide-mouth bottle or 1-L beaker with sample from a
representative area. Fill duplicate sample bottles contain-
ing the desired dechlorinating.agent with sample from the
larger container.
8.1.4 Fill sample bottles to overflowing, but take care not to
flush out the rapidly dissolving dechlorinating agent. No
air bubbles should pass through the sample as the bottle is
filled,.or be trapped ,in the sample when the bottle is
sealed.
8.2 SAMPLE PRESERVATION
8.2.1 Adjust the pH of all samples to < 2 at the time of collect-
ion, but after dechlorination, by carefully adding two drops
of 1:1 HC1 for each 40 mL of sample. Seal the sample bot-
tles, Teflon face down, and mix for 1 min. Exceptions to the
acidification requirement are detailed in Sections 8.2.2 and
8.2.3. NOTE: Do not mix the ascorbic acid or sodium thiosul-
fate with the HC1 in the sample bottle prior to sampling.
8.2.2 When sampling for THM analysis only, acidification may be
omitted if sodium thiosulfate is used to dechlorinate the
sample. This exception to acidification does not apply if
ascorbic acid is used for dechlorination.
8.2.3 If a sample foams vigorously when HC1 is added, discard that
sample. Collect a set of duplicate samples but do not acidi-
fy them. These samples must be flagged as "not acidified"
and must be stored at 4°C or below. These samples must be
analyzed within 24 hr of collection time if they are to be
analyzed for any compounds other than THMs.
502.2-13
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8.2.4 The samples must be chilled to about 4°C when collected and
maintained at that temperature until analysis. Field samples
that will not be received at the laboratory on the-day of
collection must be packaged for shipment with sufficient ice
to ensure that they will arrive at the laboratory with a
substantial amount of ice remaining in the cooler.
8.3 SAMPLE STORAGE
8.3.1 Store samples at < 4°C until analysis. The sample storage
area must be free of organic solvent vapors and direct or
intense light.
8.3.2 Analyze all samples within 14 days of collection. Samples
not analyzed within this period must be discarded and re-
placed.
8.4 FIELD REAGENT BLANKS (FRB)
8.4.1
8.4.2
Duplicate FRBs must be handled along with each sample set,
which is composed of the samples collected from the same
general sample site at approximately the same time. At the
laboratory, fill field blank sample bottles with reagent
water and sample preservatives, seal, and ship to the sam-
pling site along with empty sample bottles and back to the
laboratory with filled sample bottles. Wherever a set of
samples is shipped and stored, it is accompanied by appropri-
ate blanks. FRBs must remain hermetically sealed until
analysis.
Use the same procedures used for samples to add sodium thio-
sulfate or ascorbic acid and HC1 to blanks (Sect. 8.1.1).
The same batch of ascorbic acid and HC1 should be used for
the field reagent blanks in the field.
9. QUALITY CONTROL
9.1
9.2
Quality control (QC) requirements are the initial demonstration of
laboratory capability followed by regular analyses of laboratory
reagent blanks, field reagent blanks, and laboratory fortified
blanks. A method detection limit (MDL) must also be determined for
each analyte. The laboratory must maintain records to document the
quality of the data generated. Additional quality'control practices
are recommended.
Initial demonstration of low system background. Before any samples
are analyzed, it must be demonstrated that a laboratory reagent
blank (LRB) is reasonably free of contamination that would prevent
the determination of any analyte of concern. Sources of background
contamination are glassware, purge gas, sorbents, and equipment.
Background contamination must be reduced to an acceptable level
502.2-14
-------
before proceedi'ng with the next section. In general background from
method analytes should be below the method detection limit.
9.3 Initial demonstration of capability.
9.3.1 Demonstration of laboratory accuracy and precision. Analyze
four to seven replicates of a laboratory fortified blank
containing each analyte of concern at a concentration in the
range of 0.1-5 /zg/L. This concentration should represent a
concentration of ten times the MDL or a concentration hear
the middle of the calibration range demonstrated (Sect,. 10).
It is recommended that a QCS from a source different than the
calibration standards be used for this set of LFBs, since it
will serve as a che.ck to verify the accuracy of the standards
used to generate the calibration curve. This is particularly
useful if the laboratory is using-'the method for the first
time, and has no historical data base for standards. Prepare
each replicate by adding an appropriate aliquot of a quality
control sample to reagent water. Also add the appropriate
amounts of internal standard and surrogates if they are being
used. If it is expected that field samples will contain a
dechlorinating agent and HC1, then add these to the LFBs in
the same amounts prescribed in Sect. 8.1.1. If only THMs are
to be determined and field samples do not contain HC1, then
do not acidify LFBs. Analyze each replicate according to the
procedures described in Sect. 11.
9.3.2 Calculate the measured concentration of each analyte in each
replicate, the mean concentration of each analyte in all
replicates, and mean accuracy (as mean percentage of true
value) for each analyte, and the precision (as relative
standard deviation, RSD) of the measurements for each analy-
te.
9.3.3 For each analyte and surrogate, the mean accuracy, expressed
as a percentage of the true value, should be 80-120% and the
RSD should be <20%. Some analytes, particularly the early
eluting gases and late eluting higher molecular weight com-
pounds, are measured with less accuracy and precision than
other analytes. If these criteria are not met for an analy-
te, take remedial action and repeat the measurements for that
analyte to demonstrate acceptable performance before samples
are analyzed.
9.3.4 To determine the MDL, analyze a minimum of 7 LFBs prepared at
a low concentration. MDLs in Tables 2 and 4 were calculated
from samples fortified at 0.1 /zg/L, which can be used as a
guide, or use calibration data to estimate a concentration
for each analyte that will yield a peak with a 3-5 signal to
noise ratio. Analyze the 7 replicates as described in
Sect.11, and on a schedule that results in the analyses being
conducted over several days. Calculate the mean accuracy and
502.2-15
-------
standard deviation for each analyte. Calculate the MDL using
procedures described in Ref. 4. The equation for this calcu-
lation is also in Sect. 13.3.
9.3.5 Develop and maintain a system of control charts to plot the
precision and accuracy of analyte and surrogate measurements
as a function of time. Charting of surrogate recoveries is
an especially valuable activity since these are present in
every sample and the analytical results will form a signifi-
cant record of data quality.
9.4 Laboratory reagent blanks (LRBs). With each batch of samples
processed as a group within a work shift, analyze a laboratory
reagent blank to determine the background system contamination.
LRBs should contain the same additives (dechlorinating agent and
HC1) as field samples.
9.5 Assessing Laboratory .Performance. With each batch of samples
processed as a group within a work shift, analyze a single laborato-
ry fortified blank (LFB) containing each analyte of concern at a
concentration as determined in 9.3.1. LFBs should contain a dechlo-
rination agent and/or HC1 as appropriate to match the field samples
being analyzed. The minimum frequency of LFB analysis is once every
twelve hours. Use the criteria described in 9.3.3 to evaluate the
accuracy of the measurements, and to estimate whether the method
detection limits can be obtained. If acceptable accuracy and method
detection limits cannot be achieved, the problem must be located and
corrected before further samples are analyzed. Data from all field
samples analyzed since the last acceptable LFB should be considered
suspect, and duplicate samples should be analyzed, if they are
available, after the problem has been corrected. LFB results should
'be added to the on-going control charts to document data quality.
Since the calibration check sample in Sect. 10.3.2 and the LFB are
made the same way and since procedural standards are used, the
sample analyzed here may also be used as the calibration check in
Sect. 10.3.2.
9.6 Assessing the Internal Standard. If internal standard calibration
is used, the analyst must assess the response of the internal
standard in every LRB, FRB, LFB, CAL, and field sample. The IS
response (peak height or peak area units) must be within 20% of
the mean peak response of the IS in the CAL standards used to
develop the calibration. If this criteria cannot be met, take
remedial action. If there are interferences in field samples that
affect the measurement of the internal standard, external standard
calibration should be used (Sect. 10.3.2).
9.7 Assessing the Surrogate Analyte. Calculate the amount of the
surrogate analyte recovered in each LRB, LFB, FRB, CAL, and field
sample (Sect.10). If the surrogate recovery in blanks or calibra-
tion standards does not meet the criteria in Sect. 9.3.3., take
502.2-16
-------
remedial action. If the surrogate recovery in a field sample does
not meet the criteria in Sect 9.3.3., and data from LFBs shows the
laboratory to be in control, reanalyze the sample.
9.8 If a water sample is contaminated with an analyte, verify that it is
not a sampling error by analyzing a field reagent blank. The
results of these analyses will help define contamination resulting
from field sampling, storage and transportation activities. If the
field reagent blank shows unacceptable contamination, the analyst
should identify and eliminate the contamination.
9.9 At least quarterly, replicates of laboratory fortified blanks should
be evaluated to determine the precision of the laboratory measure-
ments. Add these results to the on-going control charts to document
data quality.
9.10 At least quarterly, analyze a quality control sample (QCS) from an
external source. If measured analyte concentrations are not of
acceptable accuracy, check the entire analytical procedure to locate
and correct the problem source.
9.11 Sample matrix effects have not been observed when this method is
used with distilled water, reagent water, drinking water, and ground
water. Therefore, analysis of a laboratory fortified sample matrix
(LFM) is not required.
9.12 Numerous other quality control measures are incorporated into other
parts of this procedure, and serve to alert the analyst to poten-
tial problems.
10. CALIBRATION AND STANDARDIZATION
10.1 Demonstration and documentation of acceptable initial calibration is
required before any samples are analyzed. In addition, acceptable
performance must be confirmed intermittently throughout analysis of
samples by performing continuing calibration checks. These checks
are required at the beginning of each work shift, but no less than
every 12 hours. Additional periodic calibration checks are good
laboratory practice. Since this method uses procedural standards,
the analysis of the laboratory fortified blank, which is required in
Sect. 9.5, may be used here as a calibration check sample.
10.2 PREPARATION OF CALIBRATION STANDARDS
10.2.1 The number of calibration solutions (CALs) needed depends on
the calibration range desired. A minimum of three CAL solu-
tions is required to calibrate a range of a factor of 20 in
concentration. For a factor of 50 use at least four stan-
dards, and for a factor of 100 at least five standards. One
calibration standard should contain each analyte of concern
at a concentration 2 to 10 times greater than the method
detection limit (Table 2 and 4) for that compound. The other
502.2-17
-------
CAL standards should contain each analyte of concern at
concentrations that define the range of the sample analyte
concentrations. When internal standard calibration is being
used, every CAL solution contains the internal standard at
same concentration (10 /Kj/L).
10.2.2 To prepare a calibration standard, add an appropriate volume
of a primary dilution standard solution to an aliquot of
reagent water in a volumetric container or sample syringe.
The reagent water used should also contain the appropriate
dechlorinating agent and/or HC1 so as to match the field
samples to be analyzed. Use a microsyringe and rapidly
inject the alcoholic standard into the water. Remove the
needle as quickly as possible after injection. Accurate
calibration standards can be prepared by injecting 20 fiL of
the primary dilution standards to 25 mL or more of reagent
water using the syringe described in section 6.4.3. Aqueous
standards are not stable in volumetric container and should
be discarded after one hour unless transferred to sample
bottle and sealed immediately as described in Sect. 8.1.2.
10.3 CALIBRATION
10.3.1 External standard calibration. Starting with the standard of
lowest concentration, analyze each calibration standard
according to Sect. 11 and tabulate peak height or area re-
sponse versus the concentration in the standard. The results
can be used to prepare a calibration curve for each compound.
Alternatively, if the ratio of response to concentration
(calibration factor) is a constant over the working range
(<10% relative standard deviation), linearity through the
origin can be assumed and the average ratio or calibration
factor can be used in place of a calibration curve.
10.3.2 Internal standard calibration. The organohalides recommended
as internal standards are: l-chloro-2-fluorobenze or 2-brom-
o-1-chloropropane and fluorobenzene. The internal standard
is added to the sample just before purging. Check the valid-
ity of the internal standard response factors daily by ana-
lyzing a calibration standard. NOTE: Since the calculated
concentrations can be strongly biased by inaccurate detector
response measurements for the internal standard or by coelut-
ion of an unknown with the internal standard, it is required
that the area measurement of the internal standard of each
sample be within ± 3 standard deviations of those obtained
from calibration standards, or ± 20% of the mean response ob-
tained from calibration standards, whichever is greater. If
they do not, then internal standards can not be used.
10.3.3 Following analysis, tabulate peak height or area responses
against concentration for each compound and the internal
502.2-18
-------
standard. Calculate the response factor (RF) for each com-
pound using Equation 1.
Equation 1
RF = iAsl_LC,. 1
(O (C.)
where
As = Response for the analyte to be measured
Ais = Response for the internal standard
Cjs = Concentration of the internal standard (#g/L)
Cs = Concentration of the analyte to be measured (/ag/L)
If RF value over the working range is constant (< 10% RSD),
the average RF can be used for calculations. Alternatively,
the results can be used to plot a calibration curve of re-
sponse versus analyte ratios, A0/A, vs. C /C- .
S IS S' 1S
10.3.4 The working calibration curve or calibration factor must be
verified by the measurement of one or more calibration stan-
dards. This must be done at least once each work shift, but
no less than once every twelve hours. Additional periodic
calibration checks are good laboratory practice. It is
highly recommended that an additional calibration check be
performed at the end of any cycle of continuous instrument.
operation, so that each set of field samples is bracketed by
calibration check standards. It is also recommended that
more that one concentration of continuing calibration stan-
dard be analyzed, in order to evaluate the accuracy of the
calibration at more than one point. If the response for any
analyte varies from the predicted response by more than ±
20%, the test must be repeated using a fresh calibration
standard. If the results still do not agree, generate a new
calibration curve. Any field samples analyzed since the last
acceptable calibration check should be considered suspect,
and should be reanalyzed if they are available.
10.4 CALIBRATION FOR VINYL CHLORIDE USING A CERTIFIED GASEOUS MIXTURE
(OPTIONAL)
10.4.1 Fill the purging device with 5.0 mL of reagent water or
aqueous calibration standard, and add internal standards.
10.4.2 Start to purge the aqueous mixture (Sect. 7.2.6). Inject a
known volume (between 100 and 2000 0L) of the calibration gas
(at room temperature) directly into the purging device with a
gas tight syringe. Slowly inject the gaseous sample through
the aqueous sample inlet needle. After completion, inject 2
mL of clean room air to sweep the gases from the inlet needle
502.2-19
-------
into the purging device. Inject the gaseous standard before
five min of the 11-min purge time have elapsed.
10.4.3 Determine the aqueous equivalent concentration of vinyl
chloride standard injected in jug/L, according to the equa-
tion:
S = 0.51 (C) (V)
where: S
Equation 1
Aqueous equivalent concentration of vinyl
chloride standard in jug/L;
Concentration of gaseous standard in ppm (v/v);
Volume of standard injected in milliliter
C
V
11. PROCEDURE
i.-'
11.1 INITIAL CONDITIONS
11.1.1 Recommended chromatographic conditions are summarized in
Sect. 6.3. Other columns or GC conditions may be used if the
requirements of Sect. 9.3 are met.
11.1.2 Calibrate the system daily as described in Sect. 10.
11.1.3 Adjust the purge gas (nitrogen or helium) flow rate to 40 mL-
/min. Attach the trap inlet to the purging device and open
the syringe valve on the purging device.
11.2 SAMPLE INTRODUCTION AND PURGING
11.2.1 To generate accurate data, samples and calibration standards
must be analyzed under identical conditions. Remove the
plungers from two 5-mL syringes and attach a closed syringe
valve to each. Allow the sample to come to room temperature,
open the sample (or standard) bottle, and carefully pOur the
sample into one of the syringe barrels to just short of
overflowing. Replace the syringe plunger, invert the sy-
ringe, and compress the sample. Open the syringe valve and
vent any residual air while adjusting the sample volume to
5.0 mL. Add 10 pi of the internal calibration standard to
the sample through the syringe valve. Close the valve. Fill
the second syringe in an identical manner from the same
sample bottle. Reserve this second syringe for a reanalysis
if necessary.
11.2.2 Attach the sample syringe valve to the syringe valve on the
purging device. Be sure that the trap is cooler than 25°C,
then open the sample syringe valve and inject the sample into
the purging chamber. Close both valves and initiate purging.
Purge the sample for 11.0 ± 0.1 min at ambient temperature.
Note: Ambient room temperature must be relatively constant.
If it varies by more than 10°C during an analysis day, or be-
502.2-20
-------
tween calibration and sample analysis, precision and accuracy
of some analytes will be affected.
11.3 SAMPLE DESORPTION - After the 11-min purge, couple the trap to the
chromatograph by switching the purge and trap system to the desorb
mode, initiate the temperature program sequence of the gas chromato-
graph and start data acquisition. Introduce the trapped materials
to the GC column by rapidly heating the trap to 180°C while backflu-
shing the trap with an appropriate inert gas flow for 4.0 ±0.1 min.
While the extracted sample is being introduced into the gas chro-
matograph, empty the purging device using the sample syringe and
wash the chamber with two 5-mL flushes of reagent water.
11.4 TRAP RECONDITIONING - After desorbing the sample for four min,
recondition the trap by returning the purge and trap system to the
purge mode. Maintain the trap temperature at 180°C. After approxi-
mately seven min, turn off the trap heater and open the syringe
valve to stop the gas flow through the trap. When the trap is cool,
the next sample can be analyzed.
12. DATA ANALYSIS AND CALCULATIONS
12.1 Identify each analyte in the sample chromatogram by comparing the
retention time of the suspect peak to retention times generated by
the calibration standards, the LFB and other fortified quality
control samples. If the retention time of the suspect peak agrees
within ± 3 standard deviations of the retention times of those
generated by known standards (Table 1 and 3) then the identification
may be considered as positive. If the suspect peak falls outside
this range or coelutes with other compounds (Table 1 and 3), then
the sample should be reanalyzed. When applicable, determine the
relative response of the alternate detector to the analyte. The
relative response should agree to within- 20% of the relative re-
sponse determined from standards.
12.2 Xylenes and other structural isomers can be explicitly identified
only if they have sufficiently different GC retention times. Accept-
able resolution is achieved if the height of the valley between two
isomer peaks is less than 25% of the sum of the two peak heights.
Otherwise, structural isomers are identified as isomeric pairs.
12.3 When both detectors respond to an analyte, quantitation is usually
performed on the detector which exhibits the greater response.
However, in cases where greater specificity or precision would
result, the analyst may choose the alternate detector. Do not
extrapolate beyond the calibration range established in Sect. 10.
If peak response exceeds the highest calibration standard, a dupli-
cate sample must be diluted and reanalyzed. Use only the multi-
point calibration data obtained in Sect. 10 for all calculations.
Do not use the daily calibration verification standard to quantitate
method analyte in samples.
502.2-21
-------
12.4 Determine the concentration of the unknowns when external standards
are used, by using the calibration curve or by comparing the peak
height or area of the unknowns to the peak height or area of the
standards as follows:
Concentration of unknown (jug/L) = (Peak height sample/Peak height
standard) x Concentration of standard (/zg/L).
12.5 Calculate analyte and surrogate concentrations when internal stan-
dards are used with the equation in Sect. 10.3.3.
12.6 Calculations should utilize all available digits of precision, but
final reported concentrations should be rounded to an appropriate
number of significant figures(one digit of uncertainty). Experience
indicates that three significant figures may be used for concentra-
tions above 99 jug/L, two significant figures for concentrations
between 1 to 99 pg/L, and 1 significant figure for lower concentra-
tions.
12.7 Calculate the total trihalomethane concentrations by summing the
four individual trihalomethane concentrations in /zg/L.
13. METHOD PERFORMANCE
13.1 This method was tested in a single laboratory using reagent water
fortified at 10 0g/L (1). Single laboratory precision and accuracy
data for each detector are presented for the method analytes in
Tables 2 and 4.
13.2 Method detection limits for these analytes have been calculated from
data collected by forcifying reagent water at 0.1 /ug/L.(l). These
data are presented in Tables 2 and 4.
13.3 Method detection limits were calculated using the formula:
MDL = S t,
where:
LCn-1,1-alpha = 0.99)
t
-------
preparing standards and sample preservatives. All are used in
extremely small amounts and pose no threat to the environment.
15. WASTE MANAGEMENT
15.1 There are no waste management issues involved with this method. Due
to the nature of this method, the discarded samples are chemically
less contaminated than when they were collected.
16. REFERENCES
1. Ho, J.S., A Sequential Analysis for Volatile Organics in Water by
Purge and Trap Capillary Column Gas Chromatograph with Photoionizat-
ion and Electrolytic Conductivity Detectors in Series, Journal of
Chromatographic Science 27(2) 91-98, February 1989.
2. Kingsley, B.A., Gin, C., Coulson, D.M., and Thomas, R.F., Gas
Chromatographic Analysis of Purgeable Halocarbon and Aromatic
Compounds in Drinking Water Using Two Detectors in Series, Water
Chlorination, Environmental Impact and Health Effects, Volume 4, Ann
Arbor Science.
3. Bellar, T.A., and J.J. Lichtenberg, The Determination of Halogenated
Chemicals in Water by the Purge and Trap Method, Method 502.1, U.S.
Environmental Protection Agency, Environmental Monitoring and
Support Laboratory, Cincinnati, Ohio 45268, April, 1981.
4. Glaser, J.A., D.L. Foerst, G.D. McKee, S.A. Quave, and W.L. Budde,
Trace Analyses for Wastewaters, Environ. Sci. Technol., 15, 1426,
1981.
5. Carcinogens - Working with Carcinogens, Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for. Occupational Safety and Health,
Publication No. 77-206, August, 1977.
6. OSHA Safety and Health Standards, (29 CFR 1910), Occupational Safety
and Health Administration, OSHA 2206.
7. Safety in Academic Chemistry Laboratories, American Chemical Society
Publication, Committee on Chemical Safety, 4th Edition, 1985.
8. Bellar, T.A. and J.J. Lichtenberg, The Determination of Synthetic
Organic Compounds in Water by Purge and Sequential Trapping Capil-
lary Column Gas Chromatography, U.S. Environmental Protection
Agency, Environmental Monitoring and Support Laboratory, Cincinnati,
Ohio, 45268.
9. Slater, R.W., Graves, R.L. and McKee, G.D., "A Comparison of Preser-
vation Techniques for Volatile Organic Compounds in Chlorinated Tap
Waters," U.S. Environmental Protection Agency, Environmental Moni-
toring and Support Laboratory, Cincinnati, Ohio 45268.
502.2-23
-------
17. TABLES. DIAGRAMS. FLOWCHARTS. AND VALIDATION DATA
TABLE 1. RETENTION TIMES FOR VOLATILE ORGANIC COMPOUNDS
ON PHOTOIONIZATION DETECTOR (PID) AND ELECTROLYTIC
CONDUCTIVITY DETECTOR (ELCD) FOR COLUMN 1
Ana1vte(b)
Retention Time (min)a
PID ELCD
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
Di chl orodi f 1 uoromethane
Chloromethane
Vinyl Chloride
Bromomethan
Chloroethane
Tri chl orof 1 uoromethane
1,1-Dichl oroethene
Methyl ene Chloride
trans-1 , 2-Di chl oroethene
1, 1-Di chl oroethane
2, 2-Di chl oropropane
cis-1, 2-Di chl oroethene
Chloroform
Bromochl oromethane
1,1, 1-Tri chl oroethane
1 , 1-Di chl oropropene
Carbon Tetrachloride
Benzene
1, 2-Di chl oroethane
Trichl oroethene
1 , 2-Di chl oropropane
Bromodi chl oromethane
Dibromomethane
Cis-1, 3-Di chl oropropene
Toluene
Trans-1 , 3-Di chl oropropene
1,1, 2-Tri chl oroethane
Tetrachl oroethene
1,3-Dichl oropropane
Di bromochl oromethane
1,2-Dibromoethane
Chlorobenzene
Ethyl benzene
1,1,1, 2-Tetrachl oroethane
m-Xyl ene
p-Xylene
o-Xylene
Styrene
Isopropyl benzene
Bromoform
1,1,2, 2-Tetrachl oroethane
1, 2, 3-Tri chl oropropane
n-Propyl benzene
-(c)
-
9.88
-
-
-
6.14
• -
19.30
-
-
23.11
-
-
-
25.21
-
26.10
-
27.99
-
- '
-
31.38
31.95
33.01
-
33.88
-
-
-
36.56
36.72
•
36.98
36.98
38.39
38.57
39.58
-
-
-
40.87
8.47
9.47
9.93
11.95
12.37
13.49
16.18
18.39
19.33
20.99
22.88
23.14
23.64
24.16
24.77
25.24
25.47
-
26.27
28.02
28.66
29.43
29.59
31.41
-
33.04
33.21
33.90
34.00
34.73
35.34
36.59
-
36.80
-
-
-
-
-
39.75
40.35
40.81
-
502.2-24
-------
TABLE 1 (CONTINUED)
Ana1vte(b)
Internal Standards
Fluorobenzene
2-Bromo-l-chloropropanec
Retention Time (min)a
PIP ELCD
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Bromobenzene
1,3, 5-Tri methyl benzene
2-Chlorotoluene
4-Chlorotoluene
tert-Butyl benzene
1,2, 4-Tri methyl benzene
sec-Butyl benzene
p- Isopropyl to! uene
1,3-Dichlorobenzene
1,4-Di chlorobenzene
n-Butyl benzene
1,2-Dichlorpbenzene
1 , 2-Di bromo-3-Chl oropropane
1,2, 4-Tri chlorobenzene
Hexachlorobutadiene
Naphthalene
1, 2, 3-Tri chlorobenzene
40.99
41.41
41.41
41.60
42.71
42.92
43.31
43.81
44.08
44.43
45.20
45.71
-
51.43
51.92
52.38
53.34
41.03
-
41.45
41.63
-
-
-
44.11
44.47
-
45.74
48.57
51.46
51.96
-
53.37
26.84
33.08
a. Column and analytical conditions are described in Sect. -6.3.
b. Number refers to peaks in Figure 502.2-1.
c. - Dash indicates detector does not respond.
d. Interferes with trans-l,3-dichloropropene and
1,1,2-trichloroethane on the column. Use with care.
502.2-25
-------
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-------
TABLE 3. RETENTION TIMES FOR VOLATILE ORGANIC COMPOUNDS ON
PHOTOIONIZATION DETECTOR (PID) AND ELECTROLYTIC
CONDUCTIVITY DETECTOR(ELCD) FOR COLUMN 2
PID
ECLD
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
AnalvteD
Di chl orodi f 1 uoromethane
Chloromethane
Vinyl Chloride
BromomethanE
Chloroethane
Tri chl orof 1 uoromethane
1,1-Dichloroethene
Methyl ene Chloride
trans-1 , 2-Di chl oroethene
1,1-Di chloroethane
2,2-Dichloropropane
cis-1, 2-Di chl oroethene
Chloroform
Bromochl oromethane
1,1, 1-Tri chl oroethane
1, 1-Dichloropropene
Carbon Tetrachloride
1, 2-Di chl oroethane
Benzene
Trichloroethene
1 , 2-Di chl oropropane
Bromodi chl oromethane
Dibromomethane
Cis-l,3-Dichloropropene
Toluene
Trans-1, 3-Di chl oropropene
1 , 1 , 2-Tri chl oroethane
1 , 3-Di chl oropropane
Tetrachl oroethene
Di bromochl oromethane
1,2-Dibromoethane
Chlorobenzene
1,1,1, 2-Tetrachl oroethane
Ethyl benzene
m-Xyl ene
p-Xylene
o-Xylene
Styrene
Isopropyl benzene
Bromoform
1,1,2, 2-Tetrachl oroethane
1 , 2, 3-Tri chl oropropane
n-Propyl benzene
Bromobenzene
RTfmin}8
-(c)
8.57
_
_
-
14.46
-
17.61
-
-
21.52
-
-
-
24.07
-
-
25.06
2 7; 99
-
-
-
30.40
31.58
32.11
-
-
33.85
-
_
36.76
-
36.92
37.19
37.19
38.77
38.90
40.04
-
-
-
41.51
41.73
RSD
0.06
0.08
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
RTYmin}3
7.36
8.09
8.58
10.39
10.74
11.85
14.47
16.46
17.62
19.25
21.36
21.52
22.08
22.69
23.53
24.08
24.47
24.95
27.15
27.73
28.57
28.79
30.41
32.13
32.69
33.57
33.86
34.58
35.29
36.87
36.87
_
_
_
—
_
40.19
40.64
41.18
41.75
RSD
0.06
0.06
0.08
0.06
0.05
0.07
0.07
0.04
0.03
0.03
0.03
0.02
0.02
0.02
0.02
0.02
0.02
0.01
0.01
0.01
0.02
0.01
0.02
0.01
0.01
0.01
.0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
502.2-28
-------
TABLE 3 (CONTINUED)
PID
Anal vie*
RKminr RSD
Internal Standards
1-Chloro-2-Fluorobenzene
37.55
0.01
ECLD
RKminr RSD
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
1 , 3 , 5-Tri methyl benzene
2-Chlorotoluene
4-Chlorotoluene
tert-Butyl benzene
1,2, 4-Trimethyl benzene
sec-Butyl benzene
p-Isopropyl toluene
1 , 3-Di chl orobenzene
1 , 4-Di chl orobenzene
n-Butyl benzene
1,2-Dichlorobenzene
1 , 2-Di bromo-3-Chl oropropane
1,2, 4-Tri chl orobenzene
Hexachl orobutadi ene
Naphthalene
1, 2, 3-Tri chl orobenzene
42.08
42.20
42.36
43.40
43.55
44.19
44.69
45.08
45.48
46.22.
46.88
53.26
53.86
54.45
55.54
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
-
0.01
0.01
0.01
0.01
42.21
42.36
-
-
-
-
45.09
45.48
-
46.89
49.84
53.26
53.87
-
55.54
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
37.56
0.01
a. Column and analytical conditions are described in Sect. 6.3.4.
b. Number refers to peaks in Figure 502.2-2.
c. - Dash indicates detector does not respond.
502.2-29
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502.2-31
-------
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FIGURE 1. PURGING DEVICE
502.2-32
-------
PACKING PROCEDURE
CONSTRUCTION
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SCUD
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FIGURE 2. TRAP PACKINGS AND CONSTRUCTION TO INCLUDE
DESORB CAPABILITY
502.2-33.
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1
THIS PAGE LEFT BLANK INTENTIONALLY
502.2-36
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METHOD 504.1 1,2-DIBROMOETHANE (EDB), l,2-DIBROMO-3-CHLORO-
PROPANE (DBCP), AND 1,2,3-TRICHLOROPROPANE (123TCP) IN
WATER BY MICROEXTRACTION AND GAS CHROMATOGRAPHY
Revision 1.1
Edited by J.W. Munch (1995)
T. W. Winfield - Method 504, Revision 1.0 (1986)
T. W. Winfield - Method 504, Revision 2.0 (1989)
James W. Eichelberger - Method 504.1, Revision 1.0 (1993)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
504.1-1
-------
METHOD 504.1
1,2-DIBROMOETHANE (EDB), l,2-DIBROMO-3-CHLOROPROPANE (DBCP), AND
1,2,3-TRICHLOROPROPANE (123TCP) IN WATER BY
MICROEXTRACTION AND GAS CHROMATOGRAPHY
SCOPE AND APPLICATION
1.1
This method (1-3) is applicable to the determination of the
following compounds in finished drinking water and groundwater:
Analvte
1,2-Dibromoethane
1,2-Di bromo-3-Chloropropane
1,2,3-Trichloropropane
Chemical Abstract Services
Registry Number
106-93-4
96-12-8
96-18-4
1.2
1.3
For compounds other than the above mentioned analytes, or for other
sample sources, the analyst must demonstrate the usefulness of the
method by collecting precision and accuracy data on actual samples
and provide qualitative confirmation of results by gas
chromatography/mass spectrometry (GC/MS) (4).
The experimentally determined method detection limits (MDL) (5) for
EDB and DBCP were calculated to be 0.01 0g/L and the MDL for 123TCR
was calculated to be 0.02 /tg/L. The method has been useful for
these anal'/tes over a concentration range from approximately 0.03 to
200 /jg/L. Actual detection limits are highly dependent upon the
characteristics of the gas chromatographic system used.
2. SUMMARY OF METHOD
2.1
2.2
2.3
Thirty-five mL of sample are extracted with 2 mL of hexane. Two /zL
of the extract are then injected into a gas chromatograph equipped
with a linearized electron capture detector for separation and
detection. Analytes are quantitated using procedural standard
calibration (Sect. 3.12).
The extraction and analysis time is 30 to 50 min per sample
depending upon the analytical conditions chosen.
Confirmatory evidence should be obtained for all positive results.
This data may be obtained by using retention data from a dissimilar
column, or when concentrations are sufficiently high by GC/MS.
Purge and trap techniques using Methods 502.2 or 524.2 may also be
used. Confirmation of all positive results of EDB are especially
important, because of the potential for misidentification of
dibromochloromethane (DBCM) as EDB.
504.1-2
-------
3. DEFINITIONS
3.1 LABORATORY DUPLICATES (LD1 and LD2) — Two aliquots of the same
sample taken in the laboratory and analyzed separately with
identical procedures. Analyses of LD1 and LD2 indicate the
precision associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures.
3.2 FIELD DUPLICATES (FD1 and FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as well as with
laboratory procedures.
3.3 LABORATORY REAGENT BLANK (LRB) — An aliquot of reagent water or
other blank matrix that is treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents, internal
standards, and surrogates that are used with other samples. The LRB
is used to determine if method analytes or other interferences are
present in the laboratory environment, the reagents, or the
apparatus.
3.4 FIELD REAGENT BLANK (FRB) — An aliquot of reagent water or other
blank matrix that is placed in a sample container in the laboratory
and treated as a sample in .all respects, including shipment to the
sampling site, exposure to sampling site conditions, storage,
preservation and all analytical procedures. The purpose of the FRB
is to determine if method analytes or other interferences are
present in the field environment.
3.5 INSTRUMENT PERFORMANCE CHECK SOLUTION (IPC) — A solution of one or
more ,method analytes, surrogates, internal standards, or other test
substances used to evaluate the performance of the instrument system
with respect to a defined set of criteria.
3.6 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water or
other blank matrix to which known quantities of the method analytes
are added in the laboratory. The LFB is analyzed exactly like a
sample, and its purpose is to determine whether the methodology is
in control, and whether the laboratory is capable of making accurate
and precise measurements.
3.7 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
504.1-3
-------
3.8 STOCK STANDARD SOLUTION (SSS) - A concentrated solution containing
one or method analytes prepared in the laboratory using assayed
reference materials or purchased from a reputable commercial source.
3.9 PRIMARY DILUTION STANDARD SOLUTION (PDS) - A solution of several
analytes prepared in the laboratory from stock standard solutions
and diluted as needed to prepare calibration solutions and other
needed analyte solutions.
3.10 CALIBRATION STANDARD (CAL) - A solution prepared from the primary
dilution standard solution and stock standard solutions of the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration. J
3.11 QUALITY CONTROL SAMPLE (QCS) - A solution of method analytes of
known concentrations that is used to fortify an aliquot of LRB or
sample matrix. The QCS is obtained from a source external to the
laboratory and different from the source of calibration standards
It is used to check laboratory performance with externally prepared
test materials. K M«ICU
3.12 PROCEDURAL STANDARD CALIBRATION - A calibration method where
aqueous calibration standards are prepared and processed (e g
purged extracted, and/or derivatized) in exactly the same manner as
a sample. All steps in the process from addition of sampling
preservatives through instrumental analyses are included in the
calibration. Using procedural standard calibration compensates for
any inefficiencies in the processing procedure.
4. INTERFERENCES
4.1 Impurities contained in the extracting solvent usually account for
the majority of the analytical problems. Solvent blanks should be
analyzed on each new bottle of solvent before use. Indirect daily
checks on the extracting solvent are obtained by monitoring the
reagent water blanks (Sect. 7.2.4). Whenever an interference is
noted in the reagent water blank, the analyst should reanalyze the
extracting solvent. Low level interferences generally can be
removed by distillation or column chromatography (3). When a
solvent is purified, preservatives put into the solvent by the
manufacturer are removed thus potentially making the shelf-life
short. It is generally more economical to obtain a new source of
solvent. Interference-free solvent is defined as a solvent
containing less than the MDL of an individual analyte interference
Protect interference-free solvents by storing in an area free of
organochlorine solvents.
4.2 This liquid/liquid extraction technique efficiently extracts a wide
boiling range of non-polar organic compounds and, in addition,
extracts polar organic components of the sample with varying
efficiencies. .
504.1-4
-------
4.3 Dibromochloromethane is a common disinfection byproduct in
chlorinated drinking waters that frequently occurs at relatively
high concentrations. DBCM can elute very close to EDB, and a high
concentration of DBCM may mask a low concentration of EDB, or be
misidentified as EDB. Therefore, special care should be taken in
the identification and confirmation of EDB.
4.4 It is important that samples and working standards be contained in
the same solvent. The solvent for working standards must be the
same as the final solvent used in sample preparation. If this is
not the case, chromatographic comparability of standards to sample
may be affected.
5. SAFETY
5.1 The toxicity and carcinogenicity of chemicals used in this method
have not been precisely defined; each chemical should be treated as
a potential health hazard, and exposure to these chemicals should be
minimized. Each laboratory is responsible for maintaining awareness
of OSHA regulations regarding safe handling of chemicals used in
this method. Additional references to laboratory safety are
available (5-7) for the information of the analyst.
5.2 EDB, DBCP, and 123TCP have all been tentatively classified as known
or suspected human or mammalian carcinogens. Pure standard
materials and stock standard solutions of these compounds should be
handled in a hood or glovebox. A NIOSH/MESA approved toxic gas
respirator should be worn when the analyst handles high
concentrations of these toxic compounds.
6. EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.)
6.1 SAMPLE CONTAINERS — 40-mL screw cap vials each equipped with a
Teflon-lined cap. Individual vials shown to contain at least 40.0
mL can be calibrated at the 35.0 mL mark so that volumetric, rather
than gravimetric, measurements of sample volumes can be performed.
Prior to use, wash vials and septa with detergent and rinse with tap
and distilled water. Allow the vials and septa to air dry at room
temperature, place in a 105°C oven for one hr, then remove and allow
to cool in an area free of organic solvent vapors.
6.2 VIALS, auto sampler, screw cap with Teflon faced septa, 1.8 mL.
6.3 MICRO SYRINGES — 10, 25, and 100 /tL.
6.4 PIPETTES -- 2.0 and 5.0 mL transfer.
6.5 STANDARD SOLUTION STORAGE CONTAINERS — 15-mL bottles with Teflon
lined screw caps.
6.6 GAS CHROMATOGRAPHY SYSTEM
504.1-5
-------
6.6.1 The gas chromatograph must be capable of temperature
programming and should be equipped with a linearized electron
capture detector and a capillary column split/split!ess
injector.
6.6.2 Two gas chromatography columns are recommended. Column A
provides separation of the method analytes without
interferences from trihalomethanes (Sect. 4.3). Column A
should be used as the primary analytical column unless
routinely occurring analytes are not adequately resolved.
Column B is recommended for use as a confirmatory column when
GC/MS confirmation is not viable. Retention times for the
method analytes on these columns are presented in Table 1.
6.6.3 Column A (primary column) — DB-1, 30 m x 0.25 mm ID, 1.0 /im
film thickness fused silica capillary column or equivalent.
The linear velocity of the helium carrier gas should be about
25 cm/sec at 100°C. The column temperature is programmed to
hold at 40°C for 4 min, to increase to 240°C at 10°C/min, and
hold at 240°C for 5 min or until all expected compounds have
eluted.
6.6.4 Column B (alternative column) — DB-624, 30 m x 0.32 mm ID,
1.8 (im film thickness fused silica capillary column or
equivalent. The linear velocity of the helium carrier gas
should be about 25 cm/sec at 100°C. The column temperature
is programmed as described in Sect.6.6.3.
7. REAGENTS AND STANDARDS
7.1 REAGENTS
7.1.1 Hexane extraction solvent — UV Grade, distilled in glass
7.1.2 Methyl alcoliol — ACS Reagent Grade, demonstrated to be free
of method analytes above the MDLs.
7.1.3 Sodium chloride, NaCl — ACS Reagent Grade - For pretreatment
before use, pulverize a batch of NaCl and place in a muffle
furnace at room temperature. Increase the temperature to
400°C for 30 min. Place in a bottle and cap.
7.1.4 Sodium thiosulfate, Na2S20,, ACS Reagent Grade — For
preparation of solution (40 mg/mL), dissolve 1 g of Na2S203
in reagent water and bring to 25-mL volume in a volumetric
flask.
7.2 REAGENT WATER — Reagent water is defined as water free of
interferences above the analyte MDLs.
7.2.1 Reagent water can be generated by passing tap water through a
filter bed containing activated carbon. Change the activated
504.1-6
-------
carbon when there is evidence that volatile organic compounds
are breaking through the carbon.
7.2.2 A Mi Hi pore Super-Q Water System or its equivalent may be
used to generate deionized reagent water.
7.2.3 Reagent water may also be prepared by boiling water for
15 min. Subsequently, while maintaining the temperature at
90°C, bubble a contaminant-free inert gas through the water
at 100 mL/min for 1 hr. While still hot, transfer the water
to a narrow mouth screw cap bottle with a Teflon seal.
7.2.4 Test reagent water each day it is used by analyzing it
according to Sect. 11.
7.3 STOCK STANDARD SOLUTIONS — These solutions may be purchased as
certified solutions or prepared from pure standard materials using
the following procedures:
7.3.1 Place about 9.8 mL of methanol into a 10-mL ground-glass
stoppered volumetric .flask. Allow the flask to stand,
unstoppered, for about 10 min and weigh to the nearest 0.1
mg.
7.3.2 Use a 100-#L syringe and immediately add two or more drops of
standard material to the flask. Be sure that the standard
material falls directly into the methanol without contacting
the neck of the flask.
7.3.3 Reweigh, dilute to volume, stopper, then mix by inverting the
flask several times. Calculate the concentration in
micrograms per microliter from the net gain in weight.
7.3.4 Store stock standard solutions in 15-mL bottles equipped with
Teflon lined screw caps. Methanol solutions prepared from
liquid analytes are stable for at least four weeks when
stored at 4°C.
7.4 PRIMARY DILUTION STANDARD SOLUTIONS — Use stock standard solutions
to prepare primary dilution standard solutions that contain all
three analytes in methanol. The primary dilution standards should
be prepared at concentrations that can be easily diluted to prepare
aqueous calibration standards (Sect. 10.1.1) that will bracket the
working concentration range. Store the primary dilution standard
solutions with minimal headspace and check frequently for signs of
deterioration or evaporation, especially just before preparing
calibration standards. The storage time described for stock
standard solutions in Sect. 7.3.4 also applies to primary dilution
standard solutions.
504.1-7
-------
7.5 LABORATORY FORTIFIED BLANK (LFB) SAMPLE CONCENTRATE (0.25 fig/ml) —
Prepare an LFB sample concentrate of 0.25 /ig/mL of each analyte from
the stock standard solutions prepared in Sect. 7.3.
7.6 MDL CHECK SAMPLE CONCENTRATE (0.02 /ig/mL) — Dilute 2 mL of LFB
sample concentrate (Sect. 7.5) to 25 mL with methanol.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 SAMPLE COLLECTION
8.1.1 Replicate field reagent blanks (FRB) must be handled along
with each sample set, which is composed of the samples
collected from the same general sampling site at
approximately the same time. At the laboratory, fill a
minimum of two sample bottles with reagent water, seal, and
ship to the sampling site along with sample bottles.
Wherever a set of samples is shipped and stored, it must be
accompanied by the FRB.
8.1.2 Collect all samples in 40-mL bottles into which 3 mg of
sodium thiosulfate crystals have been added to the empty
bottles just prior to shipping to the sampling site.
Alternatively, 75 /*L of freshly prepared sodium thiosulfate
solution (40 mg/mL) may be added to empty 40-mL bottles just
prior to sample collection. This dechlorinati'ng agent must
be added to each sample to avoid the possibility of reactions
that may occur between residual chlorine and indeterminant
contaminants present in some solvents, yielding compounds
that may subsequently interfere with the analysis. .The
presence of sodium thiosulfate will arrest further formation
of DBCM (See Sect. 4.3).
8.1.3 When sampling from a water tap, open the tap and allow the
system to flush until the water temperature has stabilized
(usually about 10 min). Adjust the flow to about 500 mL/min
and collect samples from the flowing stream.
8.1.4 When sampling from a well, fill a wide-mouth bottle or beaker
with sample, and carefully fill 40-mL sample bottles.
8.2 SAMPLE PRESERVATION
8.2.1 The samples must be chilled to 4°C or less at the time of
collection and maintained at that temperature until analysis.
Field samples that will not be received at the laboratory on
the day of collection must be packaged for shipment with
sufficient ice to ensure that they will be <4°C on arrival at
the laboratory.
504.1-8
-------
8.3 SAMPLE STORAGE
8.3.1 Store samples and field reagent blanks together at 4°C until
analysis. The sample storage area must be free of organic
solvent vapors.
8.3.2 Because 1,2,3-trichloropropane has been added to the analyte
list in this method and has been found to have a 14 day
maximum holding time in studies conducted for Method 524.2
(4), all samples must be extracted within 14 days of
collection. Samples not analyzed within this period must be
discarded and replaced. Because of the potential for solvent
evaporation, it is preferred that extracts be analyzed
immediately following preparation. When necessary, extracts
may be stored in tightly capped vials (Sect. 6.2) at 4°6 or
less for up to 24 hr.
9. QUALITY CONTROL .
9.1 Each laboratory that uses this method is required to operate a
formal quality control program. The minimum requirements of this
program consist of an initial demonstration of laboratory capability
and an ongoing analysis of field reagent blanks (FRB), laboratory
reagent blanks (LRB), laboratory fortified blanks (LFB), laboratory
fortified sample matrix (LFM), and quality control samples (QCS) to
evaluate and document data quality. Ongoing data quality checks are
compared with established performance criteria to determine if the
results of analyses meet the performance characteristics of the
method.
9.1.1 The analyst must make an initial determination of the method
detection limits and demonstrate the ability to generate
acceptable precision with this method. This is established
as described in Sect. 9.2.
9.1.2 In recognition of advances that are occurring in chromato-
graphy, the analyst is permitted certain options to improve
the separations or lower the cost of measurements. Each time
such a modification is made to the method, the analyst is
required to repeat the procedure in Sect. 9.2.
9.1.3 Each day, the analyst must analyze a laboratory reagent blank
(LRB) and a field reagent blank, if applicable (Sect. 8.1.1),
to demonstrate that interferences from the analytical system
are under control before any samples are analyzed. In .
general, background interferences co-eluting with method
analytes should be below the method detection limits.
9.1.4 The laboratory must, on an ongoing basis, demonstrate through
the analyses of laboratory fortified blanks (LFB) that the
operation of the measurement system is in control. This
504.1-9
-------
procedure is described in Sect. 9.3. The frequency of the
LFB analyses is equivalent to 10% of all samples analyzed.
9.1.5 The laboratory should demonstrate the ability to analyze low
level samples weekly. The procedure for low level LFB
samples is described in Sect. 9.4.
9.2 Initial Demonstration of Capability
9.2.1 Prepare four to seven LFBs at a concentration equal to 10
times the MDL or at a concentration in the middle of the
calibration range established in Sect. 10.
9.2.2 Analyze the LFBs according to the method beginning in Sect.
JL Ji •
9.2.3 Calculate the mean concentration found (X) in /zg/L, and the
standard deviation of the concentrations in /jg/L, for each
analyte.
9.2.4 For each analyte, X should be between 70% and 130% of the
true value. The RSD should be 20% or less. If the results
for all three analytes meet these criteria, the system
performance is acceptable. If any analyte fails to meet the
criteria, correct the source of the problem and repeat the
test.
CAUTION: No attempts to establish low detection limits
should be made before instrument optimization and adequate
conditioning of both the column and the GC system.
Conditioning includes the processing of LFB and LFM samples
containing moderate analyte concentrations.
9.2.5 Determination of MDL. Prepare 4-7 LFBs at a low
concentration. Use the concentrations in Tables 2 and 3 as a
guideline, or use calibration data obtained (Sect. 10) to
estimate a concentration for each analyte that will produce a
chromatographic peak with a 3-5 signal to noise ratio. It is
recommended that LFBs for determination of the MDL be
prepared and analyzed over a period of several days, so that
day to day variations will be reflected in the precision
data.
9.2.6 Analyze the LFBs as directed in Sect. 11. Calculate the mean
amount recovered and the standard deviation of these
measurements. Use the standard deviation and the equation in
Sect. 13 to calculate the MDL.
9.3 Assessing Laboratory Performance. The laboratory must demonstrate
that the measurement system is in control by analyzing an LFBs of
the analytes at 0.25 fj.g/1 concentration level. This must be
504.1-10
-------
demonstrated on a frequency equivalent to 10% of the sample load, or
1 per batch of samples extracted, whichever is greater.
9.3.1 Prepare an LFB sample (0.25 jtig/L) by adding 35 jil of LFB
concentrate (Sect. 7.5) to 35 mL of reagent water in a 40-mL
bottle.
9.3.2 Immediately analyze the LFB sample according to Sect. 11 and
calculate the recovery for each analyte. The recovery should
be between 70% and 130% of the expected value.
9.3.3 If the recovery for either analyte falls outside the
designated range, the analyte fails the acceptance criteria.
A second LFB containing each analyte that failed must be
analyzed. .Repeated failure, however, will confirm a general
problem with the measurement system. If this occurs, locate
and correct the source of the problem and repeat the test.
9.3.4 Since this LFB is prepared in the same manner as a
calibration verification standard, this LFB data can also be
used to satisfy the calibration requirement in Sect. 10.1.4.
9.4 Assessing Laboratory Sensitivity. The laboratory should demonstrate
the ability to analyze low level samples for EDB and DBCP weekly.
9.4.1 Prepare an MDL check sample (a LFB fortified at 0.02 /jg/L)
and immediately analyze according to the method in Sect. 11.
9.4.2 The instrument response must indicate that the laboratory's
MDL is distinguishable from instrument background signal. If
it is not, correct the problem (increase sensitivity) and
repeat Sect. 9.4.1.
9.4.3 For each analyte, the recovery must be between 60% and 140%
of the expected value. These criteria are looser than those
in Sect. 9.2.4 and 9.3.2 because of the low concentration.
9.4.4 When either analyte fails the test, the analyst should repeat
the test for that analyte. Repeated failure, however, will
confirm a general problem with the measurement system or
faulty samples and/or standards. If this occurs, locate and
correct the source of the problem and repeat the test.
9.5 Assessing Matrix Effects. At least once in every 20 samples,
fortify an aliquot of a randomly selected,routine sample with known
amounts of the analytes. The added concentration should not be less
than the background concentration of the sample selected for
fortification. To simplify these checks, it would be convenient to
use LFM concentrations ~10X MDL. Over time, recovery should be
evaluated on fortified samples from all routine sources. Calculate
the percent recovery (R,-) for each analyte, corrected for background
concentrations measured in the unfortified sample. If the recovery
504.1-11
-------
of any such analyte falls outside the range of ± 35% of the
fortified amount, and the laboratory performance for that analyte is
shown to be in control (Sect. 9.3), .the recovery problem encountered
with the dosed sample is judged to be matrix related, not system
related. The result for that analyte in the unfortified sample is
labeled suspect/matrix to inform the data user that the results are
suspect due to matrix effects.
9.6 It is highly recommended that a laboratory establish its
ability to distinguish DBCM from EDB. This is
particularly important if samples from chlorinated sources
or unfamiliar sources are to be analyzed (Sect. 4.3).
Standards of DBCM should be analyzed periodically to
establish its retention time relative to that of EDB.
When evaluating this retention time difference, the
analyst should keep in mind that DBCM is likely to be
present in concentrations much larger than EDB, and that
the ability to detect EDB may deteriorate with increasing
DBCM concentration.
9.7 At least quarterly, a quality control sample (QCS) should be
analyzed. If measured analyte concentrations are not of acceptable
accuracy, check the entire analytical procedure to locate and
correct the problem source.
9.8 It is recommended that the laboratory adopt additional quality
assurance practices for use with this method. The specific
practices that are most productive depend upon the needs of the
laboratory and the nature of the samples. Field duplicates may be
analyzed to assess the precision of the environmental measurements.
Whenever possible, tf.e laboratory should analyze standard reference
materials and participate in relevant performance evaluation
studies.
10. CALIBRATION AND STANDARDIZATION
10.1 CALIBRATION AND STANDARDIZATION
10.1.1 At least three calibration standards are needed; five are
recommended. Guidance on the number of standards is as
follows: A minimum of three calibration standards are
required to calibrate a range of a factor of 20 in
concentration. For a factor of 50 use at least four
standards, and for a factor of 100 at least five standards.
The lowest standard should represent analyte concentrations
near, but above, their respective MDLs. The remaining
standards should bracket the analyte concentrations expected
in the sample extracts, or should define the working range of
the detector.
10.1.2 To prepare a calibration standard (CAL), add an appropriate
volume of a primary dilution standard solution to an aliquot
504.1-12
-------
of reagent water in a volumetric flask. If < 20 /iL of a
standard is added to the reagent water, poor precision may
result. Use a 25-/JL micro syringe and rapidly inject the
alcoholic standard into the expanded area of the filled
volumetric flask. Remove the needle as quickly as possible
after injection. Mix by inverting the flask several times.
Discard the contents contained in the neck of the flask.
Aqueous standards should be prepared fresh and extracted
immediately after preparation Unless sealed and stored
without headspace as described in Sect. 8. Alternatively,
measure a 35-mL volume of reagent water in a 50-mL graduated
cylinder and transfer it to a 40-mL sample container (Sect.
6.1). Use a micro syringe to inject the standard into the
reagent water. Cap and mix gently.
10.1.3 Analyze each calibration standard according to Sect. 11 and
record the peak height or area response from each standard.
Create a calibration curve by plotting peak area response
versus the concentration in the standard. Alternatively, if
the ratio of concentration to response (calibration factor)
is a constant over the working range (< 20% relative standard
deviation), linearity through the origin can be assumed and
the average ratio or calibration factor can be used in place
of a calibration curve.
10.1.4 Verify the calibration daily by the analysis of 1 or more
calibration standards for each 12 hr shift of operation. It
is recommended that a calibration standard be analyzed at the
beginning of each period of operation, and also at the end of
each period of continuous instrument operation. Vary the
concentration of the calibration standards used for
verification, so that several points in the calibration range
are verified. NOTE: The data presented in Tables 1-3 were
obtained on a chromatographic system that was calibrated
daily. Because of the sensitivity required in this method it
may be necessary for some laboratories to calibrate daily, in
order to meet the QC criteria in Section 9.
10.2 INSTRUMENT PERFORMANCE — Check the performance of the entire
analytical system daily using data gathered from analyses of
laboratory reagent blanks and standards.
10.2.1 Significant peak tailing of the target compounds in the
chromatogram must be corrected. Tailing problems are
generally traceable to active sites on the GC column,
improper column installation, or problems with the operation
of the detector.
11. PROCEDURE
11.1 SAMPLE PREPARATION
504.1-13
-------
11.1.1 Remove samples and standards from storage and allow them to
reach room temperature.
11.1.2 For samples and field reagent blanks, contained in 40-mL
bottles, remove the container cap. Discard a 5-mL volume
using a 5-mL transfer pipette or 10-mL graduated cylinder.
Replace the container cap and weigh the container with
contents to the nearest 0.1 g and record this weight for
subsequent sample volume determination (Sect. 11.3). NOTE:
It is important not to use a graduated cylinder or other
means to transfer the sample to another container prior to
extraction. Loss of volatile compounds will occur each time
the sample is poured or otherwise transferred.
11.2 MICROEXTRACTION AND ANALYSIS
11.2.1 Remove the container cap and add 6 g NaCl (Sect. 7.1.3) to
the sample.
11.2.2 Recap the sample container and dissolve the NaCl by swirling
for about 20 sec.
11.2.3 Remove the cap and add exactly 2.0 mL of hexane using a class
A, TD, transfer or automatic dispensing pipette. Recap and
shake vigorously for 1 min. Allow the water and hexane
phases to separate. (If stored at this stage, keep the
container upside down.)
11.2.4 Remove the cap and carefully transfer 0.5 mL of the hexane
layer into an autoinjector using a disposable glass pipette.
11.2.5 Transfer the remaining hexane phase, being careful not to
include any of the water phase, into a second autoinjector
vial. Reserve this second vial at 4°C for a reanalysis if
necessary.
11.2.6 Transfer the first sample vial to an autoinjector set up to
inject 2 ill portions into the gas chromatograph for analysis.
Alternatively, 2 /iL portions of samples, blanks and standards
may be manually injected, although an autoinjector is
recommended.
11.3 DETERMINATION OF SAMPLE VOLUME
11.3.1 For samples and field blanks, remove the cap from the sample
container.
11.3.2 Discard the remaining sample/hexane mixture. Shake off the
remaining few drops using short, brisk wrist movements.
11.3.3 Reweigh the empty container with original cap and calculate
the net weight of sample by difference to the nearest 0.1 g.
504.1-14
-------
This net weight (grams) is equivalent to the volume of water
(in ml) extracted (Sect. 12.3).
12. DATA ANALYSIS AND CALCI1I
12.1 Identify the method analytes in the sample chromatogram by comparing
the retention time of the suspect peaks to retention times of the
calibration standards and the laboratory control standards analyzed
using identical conditions. The analyst should use caution in the
identification of EDB in samples from chlorinated and unknown
sources that may contain DBCM (Sect. 4.3). Confirmation procedures
in Section 2.3 should be used to verify identification of EDB.
12.2 Use the calibration curve or calibration factor (Sect 10 1 3) to
directly calculate the unconnected concentration (C-) of each
analyte in the sample (e.g., calibration factor x response).
Extracts that contain method analytes beyond the calibration ranqe
established in Sect. 10., must be diluted and reanalyzed. Do not
extrapolate beyond the range of instrument calibration Use the
multi-point calibration established in Sect.10 for all calculations
Do not use the daily calibration verification standard to quantitate
method analytes in samples.
12.3 Calculate the sample volume (V ) as equal to the net sample weight:
Vs = gross weight (Sect. 11.1.!).- bottle tare (Sect. 11.3.3).
12.4 Calculate the corrected sample concentration as:
Concentration, /ng/L = C,- x T^
S
12.5 Results should be reported with an appropriate number of significant
ngures. Experience indicates that three significant figures may be
used for concentrations above 99 fig/L, two significant figures for
concentrations between 1-99 /ig/L, and 1 significant figure for lower
VrfUnCcMLiaUlOnS.
13. METHOD PERFORMANCE
13.1 Single laboratory accuracy and precision data are presented for the
three method analytes in reagent water at concentrations of 0 1 ug/l
T^hinl Vic*' H f L1lSiS the data 9enerated using Column A and
Table 3 lists data gathered using Column B. The method detection
imits are presented in Table 1. The method detection limits (MDL)
in the table were calculated using the formula:
MDL = S t(rM ,_al ha _ o 99)
where:
t(n-i,i-aiPha = 0.99) = Student's t value for the 99% confidence
level with n-1 degrees of freedom
n = number of replicates
S = standard deviation of replicate analyses.
504.1-15
-------
14. POLLUTION PREVENTION
14.1 This method utilizes a microextraction procedure that requires the
use of very small volumes of hexane, thus making this method safe
for use by the laboratory analyst and harmless to the environment.
For information concerning pollution prevention that may be
applicable to laboratory operations, consult."Less is Better:
Laboratory Chemical Management for Waste Reduction" available from
the American Chemical Society's Department of Government Relations,
and Science Policy, 1155 16th Street N.W., Washington, D.C. 20036.
15. WASTE MANAGEMENT
15.1
It is the laboratory's responsibility to comply with all federal,
state, and local regulations governing the waste management,
particularly the hazardous waste identification rules and land
disposal restrictions, and to protect the air, water, and land by
minimizing and controlling all releases from fume hoods and bench
operations. Also, compliance is required with any sewage discharge
permits and regulations. For further information on waste
management, consult "The Waste Management Manual for Laboratory
Personnel," also available from the American Chemical Society at the
address in Sect. 14.1.
16. REFERENCES
1 Glaze, W.W., Lin, C.C., "Optimization of Liquid-Liquid Extraction
Methods for Analysis of Organics in Water," EPA-600/S4-83-052,
January 1984.
2. Henderson, J.E., Peyton, G.R. and Glaze, W.H.(1976). In
Identification and Analysis of Organic Pollutants in Water (L.H.
Keith ed.), pp. 105-111. Ann Arbor Sci. Pub!., Ann Arbor, Michigan.
3. Richard, J.J., G.A. Junk, "Liquid Extraction for Rapid Determination
of Halomethanes in Water," Journal AWWA, 69, 62, January 1977.
4. Munch, J.W., "Method 524.2- Measurement of Purgeable Organic
Compounds in Water by Capillary Column Gas Chromatography/ Mass
Spectrometry" in Methods for the Determination of Organic Compounds
in Drinking Water: Supplement 3 (1995). USEPA, National Exposure
Research Laboratory, Cincinnati, Ohio 45268.
5. Glaser, J.A. D.L. Forest, G.D. McKee, S.A. Quave, and W.L. Budde,
"Trace Analyses for Wastewaters," Environmental Science and
Technology, 15, 1426 (1981).
6. "Carcinogens-Working with Carcinogens," Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute of Occupational Safety and Health,
Publication No. 77-206, August 1977.
7. OSHA Safety and Health Standards, (29CFR1910), Occupational Safety
and Health Administration, OSHA 2206.
8. Safety in Academic Chemistry Laboratories, American Chemical Society
Publication, Committee on Chemical Safety, 4th Edition, 1985.
504.1-16
-------
17. TABLES. DIAGRAMS. FLOWCHARTS. AND VALIDATION DATA
TABLE 1. CHROMATOGRAPHIC CONDITIONS AND METHOD DETECTION LIMITS
FOR METHOD ANALYTES USING CONDITIONS IN SECTION 6.6.3
Analvte
EDB
123TCP
DBCP
Retention
Column A
9.37
12.00
17.3
Time. Min
Column B
12.47
15.37
15.0
MDL. ua/L
0.01
0.02
0.01
MDLs were calculated from 8 replicate samples fortified at
a concentration of 0.04 /ig/L of each analyte.
504.1-17
-------
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-------
TABLE 4. INTERLABORATORY STUDY OF METHOD 504 REGRESSION
EQUATIONS FOR RECOVERY AND PRECISION*
1,2-Dibromo-
Vlater Type 1.2-Dibromoethane 3-chloropropane
Applicable Cone. Range (0.05 - 6.68) M9/L (0.05 - 6.40) /ig/L
Reagent Water
Single-Analyst Precision SR = 0.041X -H 0.004 SR = 0.065X + 0.000
Overall Precision S = 0.075X + 0.008 S = 0.143X - 0.000
Recovery X = 1.072C - 0.006 X = 0.987C - 0.000
Ground Water
Single-Analyst Precision SR = 0.046X + 0.002 SR = 0.076X - 0.000
Overall Precision S = 0.102X + 0.006 S = 0.160X + 0.006
Recovery X = 1.077C - 0.001 X = 0.972C + 0.007
X s Mean recovery
C « True value for the concentration
* No interlaboratory method validation data is available for
1,2,3-Trichloropropane using Method 504, Revision 3.0.
504.1-20
-------
METHOD 505. ANALYSIS OF ORGANOHALIDE PESTICIDES AND
COMMERCIAL POLYCHLORINATED BIPHENYL (PCB) PRODUCTS
IN WATER BY MICROEXTRACTION AND GAS CHROMATOGRAPHY
Revision 2.1
Edited by J.W. Munch (1995)
T. W. Winfield - Method 505, Revision 1.0 (1986)
T. W. Winfield - Method 505, Revision 2.0 (1989)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
505-1
-------
METHOD 505
ANALYSIS OF ORGANOHALIDE PESTICIDES AND COMMERCIAL POLYCHLORINATED BIPHENYL
(PCB) PRODUCTS IN WATER BY MICROEXTRACTION AND GAS CHROMATOGRAPHY
1. SCOPE AND APPLICATION
1.1 This method (1,2,3) is applicable to the determination of the
following analytes in finished drinking water, drinking water during
intermediate stages of treatment, and the raw source water:
Analvte
Alachlor
Aldrin
Atrazine
Chlordane
alpha-Chlorodane
gamma-Chlorodane
Dieldrin
Endrin
Heptachlor
Heptachlor Epoxide
Hexachlorobenzene
Hexachlorocyclopentadi ene
Lindane
Methoxychlor
cis-Nonachlor
trans-Nonachlor
Simazine
Toxaphene
Aroclor 1016
Aroclor 1221
Aroclor 1232
Aroclor 1242
Aroclor 1248
Aroclor 1254
Aroclor 1260
Chemical Abstract Service
Registry Number
5972-
309-
1912-
57-
5103-
5103-
60-
72-
76-
1024-
118-
77-
58-
72-
39765-
122-
8001-
12674-
11104-
11141-
53469-
12672-
11097-
11096-
60-8
00-2
24-9
74-9
71-9
74-2
57-1
20-8
44-8
57-3
74-1
74-4
89-9
•43-5
•80-5
•34-9
•35-2
•11-2
•28-2
-16-5
-21-9
-29-6
-69-1
-82-5
1.2
1.3
The analyst must demonstrate the applicability of the method by
collecting precision and accuracy data on fortified samples (i.e.,
groundwater, tap water) (4) and provide qualitative confirmation of
results by Gas Chromatography/Mass Spectrometry (GC/MS) (5), or by GC
analysis using dissimilar columns.
Method detection limits (MDL) (6) for the above organohalides and
Aroclors have been experimentally determined (Sect. 13.2). Actual
detection limits are highly dependent upon the characteristics of the
gas chromatographic system used (e.g. column type, age, and proper
conditioning; detector condition; and injector mode and condition).
505-2
-------
1.4 This method is restricted to use by or under the supervision of
analysts experienced in the use of GC and in the interpretation of gas
chromatograms. Each analyst must demonstrate the ability to generate
acceptable results with this method using the procedure described in
Sect. 11.
2. SUMMARY OF METHOD
2.1 Thirty-five mL of sample are extracted with 2 ml of hexane. One to
two ill of the extract are then injected into a gas chromatograph
equipped with a linearized electron capture detector for separation
and analysis. Analytes are quantitated using procedural standard
calibration (Sect 3.12).
2.2 The extraction and analysis time is 40 to 70 min per sample depending
upon the analytes and the analytical conditions chosen. (See Sect
6.9).
3. DEFINITIONS
3.1 LABORATORY DUPLICATES (LD1 and LD2) - Two sample aliquots taken in
the analytical laboratory and analyzed separately with identical
procedures. Analyses of LD1 and LD2 give a measure of the precision
associated with laboratory procedures, but not with sample collection
preservation, or storage procedures. '
3.2 FIELD DUPLICATES (FD1 and FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures. Analyses
of FD1 and FD2 give a measure of the precision associated with sample
collection, preservation and storage, as well as with laboratory
procedures. ,,
3.3 LABORATORY REAGENT BLANK (LRB) - An aliquot of reagent water that is
treated exactly as a sample including exposure to all glassware,
equipment, solvents, reagents, internal standards, and surrogates that
are used with other samples. The LRB is used to determine if method
analytes or other interferences are present in the laboratory
environment, the reagents, or the apparatus.
3.4 FIELD REAGENT BLANK (FRB) - Reagent water placed in a sample
container in the laboratory and treated as a sample in all respects,
including exposure to sampling site conditions, storage, preservation
and all analytical procedures. The purpose of the FRB is to determine
if method analytes or other interferences are present in the field
environment.
3.5 LABORATORY PERFORMANCE CHECK SOLUTION (LPC) — A solution of method
analytes, surrogate compounds, and internal standards used to evaluate
the performance of the instrument system with respect to a defined set
of method criteria.
505-3
-------
3.6 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water to
which known quantities of the method analytes are added in the
laboratory. The LFB is analyzed exactly like a sample, and its
purpose is to determine whether the methodology is in control, and
whether the laboratory is capable of making accurate and precise
measurements at the required method detection limit.
3.7 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an environ-
mental sample to which known .quantities of the method analytes are
added in the laboratory. The LFM is analyzed exactly like a sample,
and its purpose is to determine whether the sample matrix contributes
bias to the analytical results. The background concentrations of the
analytes in the sample matrix must be determined in a separate aliquot
and the measured values in the LFM corrected for background concentra-
tions.
3.8 STOCK STANDARD SOLUTION — A concentrated solution containing a single
certified standard that is a method analyte, or a concentrated
solution of a single analyte prepared in the laboratory with an
assayed reference compound. Stock standard solutions are used to
prepare primary dilution standards.
3.9 PRIMARY DILUTION STANDARD SOLUTION — A solution of several analytes
prepared in the laboratory from stock standard solutions and diluted
as needed to prepare calibration solutions and other needed analyte :
solutions.
3.10 CALIBRATION STANDARD (CAL) — A solution prepared from the primary
dilution standard solution and stock standard solutions of the
internal standards and surrogate analytes. The CAL solutions are used
to calibrate the instrument response with respect to analyte
concentration.
3.11 QUALITY CONTROL SAMPLE (QCS) — A sample matrix containing method
analytes or a solution of method analytes in a water miscible solvent
which is used to fortify reagent water or environmental samples. The
QCS is obtained from a source external to the laboratory, and is used
to check laboratory performance with externally prepared test
materials.
3.12 PROCEDURAL STANDARD CALIBRATION — A calibration method where aqueous
calibration standards are prepared and processed (e.g. purged,
extracted, and/or derivatized) in exactly the same manner as a sample.
All steps in the process from addition of sampling preservatives
through instrumental analyses are included in the calibration. Using
procedural standard calibration compensates for any inefficiencies in
the processing procedure.
4. INTERFERENCES
4.1 Method interferences may be caused by contaminants in solvents,
reagents, glassware and other sample processing apparatus that lead to
505-4
-------
4.2
4.4
discrete artifacts or elevated baselines in gas chromatograms All
reagents and apparatus must be routinely demonstrated to be free from
interferences under the conditions of the analysis by running
laboratory reagent blanks as described in Sect. 9.2.
4.1.1 Glassware must be scrupulously cleaned (2). Clean all glass-
ware as soon as possible after use-by thoroughly rinsing with
the last solvent used in it. Follow by washing with hot water
and detergent and thorough rinsing with tap and reagent water
Drain dry, and heat in an oven or muffle furnace at 400°C for 1
hr Do not heat volumetric ware. Thermally stable materials
such as PCBs, might not be eliminated by this treatment
Thorough rinsing with acetone may be substituted for the
heating. After drying and cooling, seal and store glassware in
a clean environment to prevent any accumulation of dust or
other contaminants. Store inverted or capped with aluminum
T Q I I •
4.1.2 The use of high purity reagents and solvents helps to minimize
interference problems. Purification of solvents by distilla-
tion in all-glass systems may be required. WARNING: When a
solvent is purified, stabilizers put into the solvent by the
manufacturer are removed thus potentially making the solvent
hazardous. Also, when a solvent is purified, preservatives put
into the solvent by the manufacturer are removed thus
potentially reducing the shelf-life.
Interfering contamination may occur when a sample containing low
concentrations of analytes is analyzed immediately following a sample
containing relatively high concentrations of analytes. Between-sample
rinsing of the sample syringe and associated equipment with hexane can
minimize sample cross contamination. After analysis of a sample
containing high concentrations of analytes, one or more injections of
hexane should be made to ensure that accurate values are obtained for
the next sample.
Matrix interferences may be caused by contaminants that are coextract-
ed from the sample. Also, note that all the analytes listed in the
scope and application section are not resolved from each other on any
one column, i.e., one analyte of interest may be an interferant for
another analyte of interest. The extent of matrix interferences will
vary considerably from source to source, depending upon the water
sampled. Cleanup of sample extracts may be necessary Analyte
identifications should be confirmed (Sect. 11.4).
It is important that samples and working standards be contained in the
same solvent The solvent for working standards must be the same as
the final solvent used in sample preparation. If this is not the
case, chromatographic comparability of standards to sample may be
affected.
505-5
-------
4.5 Caution must be taken in the determination of endrin since it has been
reported that the splitless injector may cause endrin degradation (7).
The analyst should be alerted to this possible interference resulting
in an erratic response for endrin.
4.6 Variable amounts of pesticides and commercial PCB products from
aqueous solutions adhere to glass surfaces. It is recommended that
sample transfers and glass surface contacts be minimized, and that
adequate rinsing of glass surfaces be performed.
4.7 Aldrin, hexachlorocyclopentadiene and methoxychlor are rapidly
oxidized by chlorine. Dechlorination with sodium thiosulfate at time
of collection will stop further oxidation of these compounds.
4.8 WARNING: An interfering, erratic peak has been observed within the
retention window of heptachlor during many analyses of reagent, tap,
and groundwater. It appears to be related to dibutyl phthalate;
however, the specific source has not yet been definitively determined.
The observed magnitude and character of this peak randomly varies in
numerical value from successive injections made from the same vial.
SAFETY
5,1 The toxicity and carcinogenicity of chemicals used in this method have
not been precisely defined; each chemical should be treated as a -
potential health hazard, and exposure to these chemicals should be
minimized. Each laboratory is responsible for maintaining awareness
of OSHA regulations regarding safe handling of chemicals used in this
- method. Additional references to laboratory safety are available
(8-10) for the information of the analyst.
5.2 The following organohalides have been tentatively classified as known
or suspected human or mammalian carcinogens: aldrin, commercial PCB
products, chlordane, dieldrin, heptachlor, hexachlorobenzene, and
toxaphene. Pure standard materials and stock standard solutions of
these compounds should be handled in a hood or glovebox.
5.3 WARNING: When a solvent is purified, stabilizers put into the solvent
by the manufacturer are removed thus potentially making the solvent
hazardous.
EQUIPMENT AND SUPPLIES (All specifications are suggested.
are included for illustration only.)
Catalog numbers
6.1 SAMPLE CONTAINERS - 40-mL screw cap vials (Pierce #13075 or
equivalent) each equipped with a size 24 cap with a flat, disc-like
TFE facing backed with a polyethylene film/foam extrusion (Fisher
#02-883-3F or equivalent). Prior to use, wash vials and septa with
detergent and rinse with tap and distilled water. Allow the vials and
septa to air dry at room temperature, place the vials in a 400°C oven
505-6
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for one hour, then remove and, allow to cool in an area known to be
free of organics.
6.2 VIALS - auto sampler, screw cap with septa, 1.8 ml_, Varian
#96-000099-00 or equivalent or any other autosampler vials not
requiring more than 1.8.ml sample volumes.
6.3 AUTO SAMPLER - Hewlett-Packard 7671A, or equivalent.
6.4 MICRO SYRINGES -'lO and 100 /iL.
6.5 MICRO SYRINGE - 25 /iL with a 2-inch by 0.006-inch needle - Hamilton
702N or equivalent.
6.6 PIPETTES - 2.0 and 5.0 ml transfer.
6.7 VOLUMETRIC FLASKS - 10 and 100 mL, glass stoppered.
6.8 STANDARD SOLUTION STORAGE CONTAINERS - 15-mL bottles with PTFE-lined
screw caps.
6.9 GAS CHROMATOGRAPH — Analytical system complete^with temperature
programmable GC and split/split!ess injector suitable for use with
capillary columns and all required accessories including syringes,
analytical columns, gases, a linearized electron capture detector and
stripchart recorder. A data system is recommended for measuring peak
areas. Table 1 lists retention times observed for method analytes
using the columns and analytical conditions described below!
6.9.1 Three gas chromatographic columns are recommended. Column 1
(Sect. 6.9.2) should be used as the primary analytical column
unless routinely occurring analytes are not adequately
resolved. Validation data presented in this method were
obtained using this column. Columns 2 and 3 are recommended
for use as confirmatory columns when GC/MS confirmation is not
available. Alternative columns may be used in accordance with
the provisions described in Sect. 9.4.
6.9.2 Column 1 (Primary Column) - 0.32 mm ID x 30 M long fused silica
capillary with chemically bonded methyl polysiloxane phase
(DB-1, 1.0 urn film, or equivalent). Helium carrier gas flow is
about 25 cm/sec linear velocity, measured at 180° with. 9 psi
column head pressure. The oven temperature is programmed from
180°C to 260°C at 4°C/min and held at 260°C until all expected
compounds have eluted. Injector temperature:. 200°C.
Splitless Mode: 0.5 min. Detector temperature: 290°C.
Sample chromatograms for selected pesticides are presented in
Figures 1 and 2. Chromatograms of the Aroclors, toxaphene, and
technical chlordane are presented in Figures 3 through 11.
6.9.3 Column 2 (alternative column 1) - 0.32mm ID x 30 M long fused
silica capillary with a 1:1 mixed phase of dimethyl silicone
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and polyethylene glycol (Durawax-DX3, 0.25/zm film, or
equivalent). Helium carrier gas flow is about 25 cm/sec linear
velocity and oven temperature is programmed from 100°C to 210°C
at 8°C/min, and held at 210°C until all expected compounds have
eluted. Then the post temperature is programmed to 240°C at
8°C/min for 5 min.
6.9.4 Column 3 (alternative column 2) - 0.32mm ID x 25 M long fused
silica capillary with chemically bonded 50:50 Methyl-Phenyl
silicone (OV-17, 1.5/zm film thickness, or equivalent). Helium
carrier gas flow is about 40 cm/sec linear velocity and oven
temperature is programmed from 100°C to 260°C at 4°C/min and
held at 260°C until all expected compounds have eluted.
REAGENTS AND STANDARDS - - WARNING: When a solvent is purified,
stabilizers put into the solvent by the manufacturer are removed thus
potentially making the solvent hazardous. Also, when a solvent is
purified, preservatives put into the solvent by the manufacturer are
removed thus potentially making the shelf-life short.
7.1 REAGENTS
7.1.1 Hexane extraction solvent - UV Grade, Burdick and Jackson #216
or equivalent.
7.1.2 Methyl alcohol - ACS Reagent Grade, demonstrated to be free of
analytes.
7.1.3 Sodium chloride, NaCl - ACS Reagent Grade - For pretreatment
before use, pulverize a batch of NaCl and place in a muffle
furnace at room temperature. Increase the temperature to 400°C
and hold for 30 min. Store in a glass (not plastic) bottle to
avoid phthalate contamination..
7.1.4 Sodium thiosulfate, Na?S203, ACS Reagent Grade—For preparation
of solution (0.04 g/mL), mix 1 g of Na2S203 with reagent water
and bring to 25-mL volume in a volumetric flask. Verify the
stability of this solution and replace as necessary.
7.2 REAGENT WATER - Reagent water is defined as water free of interference
when employed in the procedure described herein.
7.2.1 A Millipore Super-Q Water System or its equivalent may be used
to generate deionized reagent water.
7.2.2 Test reagent water each day it is used by analyzing it
according to Sect. 9.2.
7.3 STOCK STANDARD SOLUTIONS - These solutions may be obtained as
certified solutions or prepared from pure standard materials using the
following procedures:
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7.3.1 Prepare stock standard solutions (5000 /zg/mL) by accurately
weighing about 0.0500 g of pure material. Dissolve the
material in methanol and dilute to volume in a 10-mL volumetric
flask. Larger volumes can be used at the convenience of the
analyst. When compound purity is assayed to be 96% or greater,
the weight can be used without correction to calculate the
concentration of the stock standard. Commercially prepared
stock standards can be used at any concentration if they are
certified by the manufacturer or by an independent source.
7.3.2 Transfer the stock standard solutions into Teflon-sealed
screw-cap bottles. Store at 4°C and protect from light. Stock
standard solutions should be checked frequently for signs of
degradation or evaporation, especially just prior to preparing
calibration standards from them.
7.3.3 Stock standard solutions must be replaced after six months, or
sooner if comparison with check standards indicates a problem.
7.4 PRIMARY DILUTION STANDARD SOLUTIONS — Use stock standard solutions to
prepare primary dilution standard solutions that contain the analytes
in methanol. The primary dilution standards should be prepared at
concentrations that can be easily diluted to prepare aqueous calibra-
tion standards (Sect. 10.2.1) that will bracket the working concentra-
tion range. Store the primary dilution standard solutions with
minimal headspace and check frequently for signs of deterioration or
evaporation, especially just before preparing calibration standards.
The storage time described for stock standard solutions in Sect. 7.3.3
also applies to primary dilution standard solutions. Note: Primary
dilution standards for toxaphene, chlordane and each of the Aroclors
must be prepared individually.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 SAMPLE COLLECTION
8.1.1 Collect all samples in 40-mL bottles into which 3 mg of sodium
thiosulfate crystals have been added to the empty bottles just
prior to shipping to the sampling site. Alternately, 75 #L Of
freshly prepared sodium thiosulfate solution (0.04 g/mL) may be
added to empty 40-mL bottles just prior to sample collection.
8.1.2 When sampling from a water tap, open the tap and allow the
system to flush until the water temperature has stabilized
(usually about 10 min). Adjust the flow to about 500 mL/min
and collect samples from the flowing stream.
8.1.3 When sampling from a well, fill a wide-mouth bottle or beaker
with sample, and carefully fill 40-mL sample bottles.
8.2 SAMPLE PRESERVATION
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8.2.1 The samples must be chilled to 4°C at the time of collection
and maintained at that temperature until the analyst is
prepared for the extraction process. Field samples that will
not be received at the laboratory on the day of collection must
be packaged for shipment with sufficient ice to insure that
they will be maintained at 4°C until arrival at the laboratory.
8.3 SAMPLE STORAGE
8.3.1 Store samples and extracts at 4°C until extraction and
analysis.
8.3.2 Extract all samples as soon as possible after collection.
Results of holding time studies suggest that all analytes with
the possible exception of heptachlor were adequately stable for
14 days when stored under these conditions. In general,
heptachlor showed inconsistent results. If heptachlor is to be
determined, samples should be extracted within 7 days of
collection. The maximum holding time for all other analytes is
14 days. Analyte stability may be affected by the matrix;
therefore, the analyst should verify that the preservation
technique is applicable to the samples under study.
8.3.3 Because of the potential for extract volume loss due to
evaporation, it is recommended that extracts be analyzed
immediately after preparation. If this is not possible,
extracts may be stored at 4°C or less in tightly capped vials
(Sect. 6.2) for up to 24 hours.
9. QUALITY CONTROL
9.1 Minimum quality control (QC) requirements are initial demonstration of
laboratory capability, analysis of laboratory reagent blanks (LRB),
laboratory fortified blanks (LFB), laboratory fortified sample matrix
(LFM), and quality control samples (QCS). A MDL for each analyte must
also be determined.
9.2 Laboratory Reagent Blanks. Before processing any samples, the analyst
must demonstrate that all glassware and reagent interferences are
under control. Each time a set of samples is extracted or reagents
are changed, an LRB must be analyzed. If within the retention time
window of any analyte the LRB produces a peak that would prevent the
determination of that analyte, determine the source of contamination
and eliminate the interference before processing samples.
9.3 Initial Demonstration of Capability
9.3.1 Select a representative fortified concentration (about 10 times
MDL or at a concentration in the middle of the calibration
range established in Section 10) for each analyte. Prepare a
standard concentrate containing each analyte at 1000 times the
selected concentration. With a syringe, add 35 fjl of the
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concentrate to each of four to seven 35 ml aliquots of reagent
water, and analyze each aliquot according to procedures
beginning in Sect. 11.
9.3.2 For each analyte the mean recovery value for these samples must
fall in the range of ± 30% of the fortified amount. The RSD
for these measurements must be 20% or less. For those
compounds that meet the acceptance criteria, performance is
considered acceptable. For those compounds that fail these
criteria, this procedure must be repeated using fresh replicate
samples until satisfactory performance has been demonstrated.
9.3.3 For each analyte, determine the MDL. Prepare a minimum of 7
LFBs at a low concentration. Use calibration data obtained in
Section 10 to estimate a concentration for each analyte that
will produce a peak with a 3-5 times signal to noise response.
Extract and analyze each replicate according to Sections 11 and
12. It is recommended that these LFBs be prepared and analyzed
over a period of several days, so that day to day precision is
reflected in the precision measurements. Calculate mean
recovery and standard deviation for each analyte. Use the
equation given in Sect.13 to calculate the MDL.
9.3.4 The initial demonstration of capability is used primarily to
preclude a laboratory from analyzing unknown samples via a new,
unfamiliar method prior to obtaining some experience with it.
It is expected that as laboratory personnel gain experience
with this method the quality of data will improve beyond those
required here.
9.4 The analyst is permitted to modify GC columns, GC conditions,
concentration techniques (i.e. evaporation techniques), internal
standards or surrogate compounds. Each time such method modifications
are made, the analyst must repeat the procedures in Sect. 9.3.
9.5 Assessing Laboratory Performance - Laboratory Fortified Blank (LFB)
9.5.1 The laboratory must analyze at least one laboratory fortified
blank (LFB) per sample set (all samples extracted within a 24-h
period). If the sample set contains more than 20 samples,
analyze one LFB for every 20 samples. Ideally the fortifying
concentration of each analyte in the LFB sample should be the
same as that selected in Sect. 9.3.1. Calculate accuracy as
percent recovery (X,-). If the recovery of any analyte falls
outside the control limits (see Sect. 9.5.2), that analyte is
judged out of control, and the source of the problem should be
identified and resolved before continuing analyses. Because
this LFB is prepared and analyzed in the same way as a
calibration verification standard, it can be used to satisfy
the calibration requirement in Sect.10.2.3.
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Note: It is suggested that one multi-component analyte
(toxaphene, chlordane or an Aroclor) LFB also be analyzed with
each sample set. By selecting a different multi-component
analyte for this LFB each work shift, LFB data can be obtained
for all of these analytes over the course of several days
9.5.2 Until sufficient data become available from within their own
laboratory, usually a minimum of results from 20 to 30
analyses, the laboratory may assess laboratory performance
against the control limits in Sect. 9.3.2 that are derived from
the data in Table 2. When sufficient internal performance data
becomes available, develop control limits from the mean percent
recovery (X) and standard deviation (S) of the percent
recovery. These data are used to establish upper and lower
control limits as follows: ;
UPPER CONTROL LIMIT = X + 3S
LOWER CONTROL LIMIT = X - 3S
After each five to ten new recovery measurements, new control.
limits should be calculated using only the most recent 20-30
data points. These calculated control limits should not exceed
the fixed limits in Sect. 9.3.2.
9.5.3 It is recommended that the laboratory periodically determine
and document its detection limit capabilities for analytes of
interest. CAUTION: No attempts to establish low detection
limits should be made before instrument optimization and
adequate conditioning of both the column and the GC system.
Conditioning includes the processing of LFB and LFM samples
containing moderate concentration levels of these analytes.
9.5.4 At least quarterly the laboratory should analyze quality
control samples (QCS). If acceptance criteria are not met,
corrective action should be taken and documented.
9.6 Assessing Analyte Recovery - Laboratory Fortified Sample Matrix (LFM)
9.6.1 The laboratory must add a known concentration to a minimum of
10% of the routine samples or one LFM per set, whichever is
greater. The fortified concentration should not be less than
the background concentration of the sample selected for
fortification. Ideally the LFM concentration should be the
same as that used for the LFB (Sect. 9.3.1). Periodically,
samples from all routine sample sources should be fortified.
9.6.2 Calculate the percent recovery (R,-) for each analyte, corrected
for background concentrations .measured in the unfortified
sample.
9.6.3 If the recovery of any such analyte falls outside the range of
± 35% of the fortified amount, and the laboratory performance
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9.7
for that analyte is shown to be in control (Sect. 9.5), the
recovery problem encountered with the dosed sample is judged to
be matrix related, not system related. The result for that
analyte in the unfortified sample is labeled suspect/matrix to
inform the data user that the results are suspect due to matrix
effects.
The laboratory may adopt additional quality control practices for use
with this method. The specific practices that are most productive
depend upon the needs of the laboratory and the nature of the samples.
For example, field or laboratory duplicates may be analyzed to assess
the precision of the environmental measurements or field reagent
blanks may be used to assess contamination of samples under site
conditions, transportation and storage.
10. CALIBRATION AND STANDARDIZATION
10.1 Establish GC operating parameters equivalent to those indicated in
Sect. 6.9. WARNING: Endrin is easily degraded in the injection port
if the injection port or front of the column is dirty. This is the
result of buildup of high boiling residue from sample injection.
Check for degradation problems daily by injecting a mid-level standard
containing only endrin. Look for the degradation products of endrin
(endrin ketone and endrin aldehyde). If degradation of endrin exceeds
20%, take corrective action before proceeding with calibration. :
Calculate percent breakdown as follows:
Total endrin degradation peak area fendrin aldehyde + endrin ketone) xlOO%
Total endrin peak area (endrin + endrin aldehyde + endrin ketone)
10.2 At least three calibration standards are needed; five are
recommended. Guidance on the number of standards is as follows: A
minimum of three calibration standards are required to calibrate a
range of a factor of 20 in concentration. For a factor of 50 use at
least four standards, and for a factor of 100 at least five
standards. The lowest standard should represent analyte
concentrations near, but above, their respective MDLs. The
remaining standards should bracket the analyte concentrations
expected in the sample extracts, or should define the working range
of the detector.
10.2.1 To prepare a calibration standard (CAL), add an appropriate
volume of a secondary dilution standard to a 35 ml aliquot of
reagent water in a 40-mL bottle. Do not add less than 20 /xl_
of an alcoholic standard to the reagent water. Use a 25-/iL
micro syringe and rapidly inject the methanolic standard into
the middle point of the water volume. Remove the needle as
quickly as possible after injection. Mix by inverting and
shaking the capped bottle several times. Aqueous standards
must be prepared fresh daily.
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10.2.2 Starting with the standard of lowest concentration, prepare,
extract, and analyze each calibration standard beginning with
Sect. 11.2 and tabulate peak height or area response versus
the concentration in the standard. The results are to be
used to prepare a calibration curve for each compound by
plotting the peak height or area response versus the concen-
tration. Alternatively, if the ratio of concentration to
response (calibration factor) is a constant over the working
range (20% RSD or less), linearity to the origin can be
assumed and the average ratio or calibration factor can be
used in place of a calibration curve. NOTE: Toxaphene,
chlordane, and Aroclor standards must be injected separately.
See Section 12.2 for information on quantitation of multi-
component analytes.
10.2.3 The working calibration curve or calibration factor must be
verified on each working day by the measurement of a minimum
of two calibration check standards, one at the beginning and
one at the end of the analysis day. These check standards
should be at two different concentration levels to verify the
calibration curve. For extended periods of analysis (greater
than 8 hrs.), it is strongly recommended that check standards
be interspersed with samples at regular intervals during the
course of the analyses. If the response for any analyte
varies from the predicted response by more than the criteria :
in Sect. 9.3.2, the test must be repeated using a fresh
calibration standard. If the results still do not agree,
generate a new calibration curve. For those analytes that
failed the calibration verification, results from field
samples analyzed since the last passing calibration should be
considered suspect. Reanalyze sample extracts for these
analytes after acceptable calibration is restored.
Note: It is suggested that a calibration verification
standard of one multi-component analyte, either chlordane,
toxaphene or an Aroclor also be analyzed each work shift. By
selecting a different multi-component analyte for this
calibration verification each work shift, continuing
calibration data can be obtained for all of these analytes
over the course of several days.
10.3 INSTRUMENT PERFORMANCE - Check the performance of the entire
analytical system daily using data gathered from analyses of
laboratory reagent blanks (LRB), (CAL), and laboratory duplicate
samples (LD1 and LD2).
10.3.1 Significant peak tailing in excess of that shown for the
target compounds in the method chromatograms (Figures 1-11)
must be corrected. Tailing problems are generally traceable
to active sites on the GC column, improper column installa-
tion, or operation of the detector.f
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10.3.2 Check the precision between replicate analyses. Poor
precision is generally traceable to pneumatic leaks,
especially at the injection port. If the GC system is
apparently performing acceptably but with decreased
sensitivity, it may be necessary to generate a new curve or
set of calibration factors to verify the decreased responses
before searching for the source of the problem.
10.3.3 Observed relative area responses of endrin (Sect. 10.1) must
meet the following general criteria:
10.3.3.1 The breakdown of endrin into its aldo and keto forms
must be adequately consistent during a period in
which a series of analyses is made. Equivalent
relative amounts of breakdown should be demonstrated
in the LRB, LFB, CAL and QCS. Consistent break-
down resulting in these analyses would suggest that
the breakdown occurred in the instrument system and
that the methodology is in control.
10.3.3.2 Analyses of laboratory fortified matrix (LFM)
samples must also be adequately consistent after
corrections for potential background concentrations
are made.
11. PROCEDURE
11.1 SAMPLE PREPARATION
11.1.1 Remove samples from storage and allow them to equilibrate to
room temperature. .
11.1.2 Remove the container caps. Withdraw and discard a 5 mL
volume using a 10-mL graduated cylinder. Replace the
container caps and weigh the containers with contents to the
nearest 0.1 g and record these weights for subsequent sample
volume determinations (Sect. 11.3).
11.2 EXTRACTION AND ANALYSIS
11.2.1 Remove the container cap of each sample, and add 6 g NaCl
(Sect. 7.1.3) to the sample bottle. Using a class A, TD
transfer or automatic dispensing pipet, add 2.0 mL of hexane.
Recap and shake vigorously by hand for 1 min. Invert the
bottle and allow the water and hexane phases to separate.
11.2.2 Remove the cap and carefully- transfer approximately 0.5 mL of
hexane layer into an autosampler vial using a disposable
glass pipet.
11..2.3 Transfer the remaining hexane phase, being careful not to
include any of the water phase, into a second autosampler
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vial. Reserve this second vial at 4°C for reanalysis if
necessary.
11.2.4 Transfer the first sample vial to an autosampler set up to
inject 1-2 fil portions into the gas chromatograph for
analysis (See Sect. 6.9 for GC conditions). Alternately, 1-2
fjl portions of samples, blanks, and standards may be manually
injected, although an autosampler is strongly recommended.
11.3 DETERMINATION OF SAMPLE VOLUME IN, BOTTLES NOT CALIBRATED
11.3.1 Discard the remaining sample/hexane mixture from the sample
bottle. Shake off the remaining few drops using short, brisk
wrist movements.
11.3.2 Reweigh the empty container with original cap and calculate
• the net weight of sample by difference to the nearest 0.1 g
(Sect. 11.1.2 minus Sect. 11.3.2). This net weight (in
grams) is equivalent to the volume (in mL) of water extracted
(Sect. 12.4). Alternatively, by using 40-mL bottles precali-
brated at 35-mL levels, the gravimetric steps can be omitted,
thus increasing the speed and ease of this extraction
process.
11.4 IDENTIFICATION OF ANALYTES
11.4.1 Identify a sample component by comparison of its retention
time to the retention time of a reference chromatogram. If
the retention time of an unknown compound corresponds, within
limits, to the retention time of a standard compound, then
identification is considered positive.
11.4.2 The width of the retention time window used to make identifi-
cations should be based upon measurements of actual retention
time variations of standards over the course of a day. Three
times the standard deviation of a retention time can be used
to calculate a suggested window size for a compound.
However, the experience of the analyst should weigh heavily
in the interpretation of chromatograms.
11.4.3 Identification requires expert judgement when sample compo-
nents are not resolved chromatographically. When peaks
obviously represent more than one sample component (i.e.,
broadened peak with shoulder(s) or valley between two or more
maxima), or any time doubt exists over the identification of
a peak on a chromatogram, appropriate alternative techniques
to help confirm peak-identification need be employed. For
example, more positive identification may be made by the use
of an alternative detector which operates on a
chemical/physical principle different from that originally
used, e.g.-, mass spectrometry, or the use of a second
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chromatography column. Suggested alternative columns are
described in Sect. 6.9.
Note: Identify multi-component analytes by comparison of the
sample chromatogram to the corresponding calibration standard
• . chromatograms of chlordane, toxaphene and the Aroclors.
Identification of multi-component analytes is made by pattern
recognition, in which the experience of the analyst is an
important factor.
12. DATA ANALYSIS AND CALCULATIONS
12.1 Identify the organohalides in the sample chromatogram by comparing
the retention time of the suspect peak to retention times generated
by the calibration standards and the laboratory fortified blanks.
. Identify the multicomponent compounds using all peaks that are
characteristic of the specific compound from chromatograms generated
with individual standards.
12.2 To quantitate multi-component analytes, one, of the following methods
should be used.
Option 1- Calculate an average response factor or linear regression
; equation for each multi-component analyte using the combined area of
all the component peaks in each of the calibration standard
chromatograms. :
Option 2- Calculate an average response factor or linear regression
equation for each multi-component analyte using the combined areas
of 3-6 of the most intense and reproducible peaks in each of the
calibration standard chromatograms.
When quantifying multi-component analytes in samples, the analyst
should use caution to include only those peaks from the sample that
are attributable to the multi-component analyte. Option 1 should
not be used if there are significant interference peaks within the
chlordane, Aroclor or toxaphene pattern.
12.3 Use the multi-point calibration curve or calibration factor (Sect.
10.2.3) to directly calculate the uncorrected concentration (Ci) of
each analyte in the sample (e.g., calibration factor x response).
Do not use the daily calibration standard to quantitate method
analytes in samples. If any analyte response exceeds the
calibration range, dilute the extract and reanalyze.
12.4 Calculate the sample volume (Vs) as equal to the net sample weight:
Vs = gross weight (Sect. 11.1,2) - bottle tare (Sect. 11.3.2).
12.5 Calculate the corrected sample concentration as:
Concentration, /ig/L = 35(C-)
(V.)
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12.6 Results should be reported with an appropriate number of significant
figures. Experience indicates that three significant figures may be
used for concentrations above 99 /*g/L, two significant figures for
concentrations between 1-99 M9/U and 1 significant figure for lower
concentrations.
13. METHOD PERFORMANCE
13.1 Single laboratory (NERL-Cincinnati) accuracy and precision at
several concentrations in reagent, ground, and tap water matrices
are presented in Table 2. These results were obtained from data
generated with a DB-1 column, and with quantitation Option 2 as
described in Section 12.2.
13.2 With these data, the method detection limits (MDL) in Table 2 were
calculated using the formula:
MDL = S t(n.1(1.alpha _ 0_99)
where:
tcn-i 1-aipha = o 99x = Student's t value for the 99%
confidence"level with n-1 degrees of freedom
n = number of replicates :
S = standard deviation of replicate analyses.
13.3 This method has been tested by 10 laboratories using reagent water
and groundwater fortified at three concentration levels. Single.
operator precision, overall precision, and method accuracy were
found to be directly related to the concentration of the analyte and
virtually independent of the sample matrix. Linear equations to
describe the relationships are presented in Table 3.
14. POLLUTION PREVENTION
14.1 This method utilizes a microextraction procedure that requires the
use of very small volumes of hexane, thus making this method safe
for use by the laboratory analyst and harmless to the environment.
For information concerning pollution prevention that may be
applicable to laboratory operations, consult "Less is Better:
Laboratory Chemical Management for Waste Reduction" available from
the American Chemical Society's Department of Government Relations,
and Science Policy, 1155 16th Street N.W., Washington, D.C. 20036.
15. WASTE MANAGEMENT
15.1 It is the laboratory's responsibility to comply with all federal,
state, and local regulations governing the waste management,
particularly the hazardous waste identification rules and land
disposal restrictions, and to protect the air, water, and land by
minimizing and controlling all releases from fume hoods and bench
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operations. Also, compliance is required with any sewage discharge
permits and regulations. For further information on waste
management, consult "The Waste Management Manual for Laboratory
Personnel," also available from the American Chemical Society at the
address in Sect. 14.1.
16. REFERENCES
1. Glaze, W.W., Lin, C.C., Optimization of Liquid-Liquid Extraction
Methods for Analysis of Organics in Water, EPA-600/S4-83-052, January
1984.
2. Henderson, J.E., Peyton, G.R. and Glaze, W.H. (1976). In
"Identification and Analysis of Organic Pollutants in Water" (L H
Keith ed.), pp. 105-111. Ann Arbor Sci. Publ., Ann Arbor, Michigan.
3. Richard, J.J., Junk, G.A., "Liquid Extraction for Rapid Determination
of Halomethanes in Water," Journal AWWA, 69, 62, January 1977.
4. "Handbook for Analytical Quality Control in Water and Wastewater
Laboratories," EPA-600/4-79-019, U. S. Environmental Protection
Agency, Environmental Monitoring and Support Laboratory Cincinnati
Ohio, 45268, March 1979. ' '
5. Munch, J. W., "Method 525.2-Determination of Organic Compounds in
Drinking Water by Liquid-Solid Extraction and Capillary Column
Chromatography/ Mass Spectrometry" in Methods for the Determination
of Organic Compounds in Drinking Water? Supplement 3 (iqgs)~ [JSEPA
National Exposure Research Laboratory, Cincinnati, Ohio 45268.
6. Glaser, J.A. et al., "Trace Analyses for Wastewaters," Environmental
Science and Technology, 15, 1426 (1981).
7. Bellar, T.A., Stemmer, P., Lichtenberg, J.J., "Evaluation of
Capillary Systems for the Analysis of Environmental Extracts "
EPA-600/S4-84-004, March 1984.
8. "Carcinogens-Working with Carcinogens," Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute of Occupational Safety and Health
Publication No. 77-206, August, 1977.
9. "OSHA Safety and Health Standards, General Industry," (29CFR1910)
Occupational Safety and Health Administration, OSHA 2206, (Revised
January 1976). . '
10. "Safety in Academic Chemistry Laboratories," American Chemical
Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.
505-19
-------
17. TABLES. DIAGRAMS. FLOWCHARTS. AND VALIDATION DATA
TABLE 1. RETENTION TIMES FOR METHOD ANALYTES
Retention Titne(a), Min
Primary Confirm. 1Confirm. 2
Hexachlorocyclopentadiene 5
Simazine 10
Atrazine 11
Hexachlorobenzene 11
Lindane 12
Alachlor 15
Heptachlor 15
Aldrin , 17
Heptachlor Epoxide 19
gamma-Chlordane 19
alpha-Chlordane 20
trans-Nonachlor 21
Dieldrin 22
Endrin 23
cis-Nonachlor 24
Methoxychlor 30
.5
.9
.2
.9
.3
.1
.9
.6
.0
.9
.9
.3
.1
.2
.3
.0
6
25
22
13
18
19
17
18
24
25
26
24
45
33
39
58
.8
.7
.6
.4
.4
.7
.5
.4
.6
.9
.6
.8
:i
.3
.0
.5
5.2
19.9
19.6
15.6
18.7
21.1
20.0
21.4
24.6
26.0
26.6
26.3
27.8
29.2
30.4
36.4
Primary(b)
Aroclor 1016
Aroclor 1221
Aroclor 1232
Aroclor 1242
Aroclor 1248
Aroclor 1254
Aroclor 1260
Chlordane
Toxaphene
13
7.
11
11
14
19
23
15
21
.6
7,
.2
.2
.8
.1
.4
.1
.7
, 14
9.0
, 14
, 13
, 16
, 21
, 24
, 15
, 22
.8
3
.7
.6
.2
.9
.9
.9
.5
, 15.
15.9,
, 13.
, 14-
, 17-
, 23.
, 26.
, 20.
, 26.
2
6
7
1
4
7
1
7
, 16.
19.1,
, 15.
, 15.
, 17.
, 24.
, 28.
, 20.
, 27.
2,
24
2,
2,
7,
9,
2,
9,
2
17
.7
17
17
19
26
29
21
.7
.7
.7,
.8,
.7
.9,
.3
19.8
22.0
32.6
Columns and analytical conditions are described in Sect. 6.9.2, 6.9.3,
and 6.9.4.
Column and conditions described in Sect. 6.9.2. More than one peak
listed does not indicate the total number of peaks characteristic of the
multi-component analyte. Listed peaks indicate only the ones chosen for
summation in the quantification.
505-20
-------
TABLE 2. SINGLE LABORATORY ACCURACY, PRECISION AND METHOD DETECTION LIMITS
(MDLS) FOR ANALYTES FROM REAGENT WATER, GROUNDWATER, AND TAP WATER3
Accuracy and Standard Deviation Data
Analvte
Alachlor
Aldrin
Atrazine
alpha-Chlordane
gamma-Chlordane
Chlordane
Dieldrin
Endrin
Heptachlor
Heptachlor Epoxide
Hexachl orobenzene
Hexachl orocycl operitadiene
Lindane
Methoxychlor
cis-Nonachlor
trans-Nonachlor
Simazine
6.2
Toxaphene
Aroclor 1016
MDL
ttd/L
0.225
0.007
2.4
0.006
0.012
0.14
0.012
0.063
0.003
0.004
0.002
0.13
0.003
0.96
0.027
0.011
6.8
1.0
0.08
Aroclor 1221 15.0
Aroclor 1232
Aroclor 1242
Aroclor 1248
Aroclor 1254
Aroclor 1260
0.48
0.31
0.102
0.102
0.189
Concen-
tration*
mil
0.50
0.05
5.0
20.0
0.06
0.35
0.06
0.35
0.17
3.4
0.10
3.6
0.10
3.6
0.032
1.2
0.04
1.4
0.003
0.09
0.15
0.35
0.03
1.2
2.10
7.03
0.06
0.45
0.06
0.35
25
60
10
80
1.0
180
3.9
4.7
3.6
3.4
1.8
1.7
2.0
1.8
Reagent Water
R* S.d
102
106
85
95
95
86
95
86
-
-
87
114
119
99
77
80
100
115
104
103
73
73
91
111
100
98
110
82
95
86
99
65
-
--
_
_
_
_
_
_
_
-
_
-
13.4
20.0
16.2
5.2
3.5
17.0
0.4
18.5
8.0
3.6
17.1
9.1
29.8
6.5
10.2
7.4
15.6
6.6
13.5
6.6
5.1
11.7
6.5
5.0
21.0
10.9
15.2
21.3
9.6
21.8
8.3
3.6
_
_
_
_
_
_
_
_
_
_•
_
_
Groundwater
R S.
86
95
86
83
94
86
95
_
67
94
94
100
37
71
90
103
91
101
87
69
88
109
—
101
93
83
94
97
59
_
_
_
_
_
_
_
_
_
..
_
_
-K
16.3
7.3
9.1
4.4
10.2
5.3
14.5
-.
10.1 .
8.6
20.2
11.3
6.8
9.8
14.2
6.9
10.9
4.4
5.1
4.8
7.7
3.4
7.2
18.3
7.1
17.2
9.2
18.0
_
_
_
„
_
--p
—
_
_
_
—
Tap
R
108
91
•J J,
85
91
83
91
105
95
92
81
106
85
200
106
112
81
100
88
191
109
103
93
_
93
87
73
86
102
67
110
114
97
92
86
96
84
85
88
Water
Sr
-R—
10.9
3 1
w • X
7.1
2.4
14.7
6 0
V * V
12.4
96
••/ • w
15.7
14.0
14.0
12.4
22.6
16.8
7.5
5.9
15.6
13.4
18.5
14.3
8.1
18.4
_
14.3
5.4
4.1
5.1
13.4
9.5
13.5
7.5
9.6
7.3
7.4
9.9
11.8
19.8
505-21
-------
Table 2 (Continued)
aData corrected for amount detected in blank and represents the mean of 5-8
samples.
method detection limit in sample in M9/L; calculated by multiplying
standard deviation (S) times the students' t value appropriate for a 99%
confidence level and a standard deviation estimate with n-1 degrees of
freedom.
CR = average percent recovery.
dSD - Standard deviation about percent recovery.
K
* Refers to concentration levels used to generate R and SR data for the three
types of water Matrices, not for MDL determinations.
- No analyses conducted.
505-22
-------
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505-24
-------
COLUMN: Fused silica capillary
LIQUID PHASE: 06-1 F V
FILM THICKNESS:. l.Oum
COLUMN DIMENSIONS: (
* * • • i
10 15 . 20
TIKE (KIN)
• • •
30
35
Figure 2. fjtract of reaoent water spiked at 20 ug/L with atrazlne.
60 ug/L with slmazlne, 0.45 ug/L with cls-nonachlor, and
0.35 ug/L with hexachlorocyclopentadlene, heptachlor,
alpha chlprdane, gamma chlordane, and trans-nonachlor.
505-25
-------
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505-34
-------
METHOD 506. Determination of Phthalate and Adi pate Esters in Drinking Water
by Liquid-Liquid Extraction or Liquid-Solid Extraction and Gas
Chromatography with Photoionization Detection
Revision 1.1
Edited by J.W. Munch (1995)
F. K. Kawahara, J. W. Hodgeson - Method 506 Revision 1.0 (1990)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
506-1
-------
METHOD 506
Determination of Phthalate and Adipate Esters in Drinking Water
by Liquid-Liquid Extraction or Liquid-Solid Extraction and
Gas Chromatography with Photoionization Detection
SCOPE AND APPLICATION
1.1 This method describes a procedure for the determination of certain
phthalate and adipate esters in drinking water by liquid/liquid or
liquid/solid extraction. The following compounds can be determined
by this method:
1.2
1.3
1.4
Arialvte
Bis (2-ethylhexyl) phthalate
Butyl benzyl phthalate
Di-n-butyl phthalate
Diethyl phthalate
Dimethyl phthalate
Bis(2-ethylhexyl) adipate
Di-n-octyl phthalate
Chemical Abstract Services
Registry Number
117-81-7
85-68-7
84-74-2
84-66-2
131-11-3
103-23-1
117-81-7
This is a capillary column gas chromatographic (GC) method
applicable to the determination of the compounds listed above in
ground water and finished drinking water. When this method is used
to analyze unfamiliar samples'for any or al,l of the compounds listed
above, compound identifications should be,supported by at least one
additional qualitative technique. Method 525.,2 provides gas
chromatograph/mass spectrometer (GC/MS) conditions appropriate for
the qualitative and quantitative confirmation of results for all the
analytes listed above, using the extract produced by this method.
This method has been validated in a single laboratory, and method
detection limits (MDLs) (1) have been determined for the analytes •
above (Table 2). Observed detection limits may vary among waters,
depending upon the nature of interferences in the sample matrix and
the specific instrumentation used.
This method is restricted to use by or under the supervision of
analysts experienced in the use of GC, and in the interpretation of
gas chromatograms obtained by a computerized system. Each analyst
must demonstrate the ability to generate acceptable results with
this method using the procedure described in Sect. 10.
SUMMARY OF METHOD
2.1 A measured volume of sample, approximately 1-L, is extracted with
methylene chloride followed by hexane using a glass separatory
funnel. The solvent extract is isolated, dried and concentrated to
506-2
-------
a volume of 5 ml or less. The extract is further concentrated by
using a gentle stream of nitrogen gas to reduce the sample volume to
1 ml or less.
Alternatively, a measured volume of sample is extracted with a
liquid-solid extraction (LSE) cartridge or disk. The LSE media are
eluted with acetonitrile followed by methylene chloride (disk
extraction) or with methylene chloride only (cartridge extraction)
The eluant is concentrated using a gentle stream of nitrogen gas or
clean air to reduce the volume to 1 ml or less.
The analytes in the extract are separated by means of capillary gas
chromatography using temperature programming. The
chromatographically separated phthalate and adipate esters are
measured with a photoionization detector, which is operating at 10
3.
DEFINITIONS
3.1
3.2
3.3
3.4
3.5
LABORATORY REAGENT BLANK (LRB) - An aliquot of reagent water that
is treated exactly as a sample including exposure to all glassware,
equipment, solvents, reagents, internal standards, and surrogates
that are used with other samples. The LRB is used to determine if
method analytes or other interferences are present in the laboratory
environment, the reagents, or the apparatus.
FIELD REAGENT BLANK (FRB), — Reagent water placed in a sample
container in the laboratory and treated as a sample in all respects,
including exposure to sampling site conditions, storage,
preservation and all analytical procedures. The purpose of the FRB
is to determine if method analytes or other interferences are
present in the field environment.
LABORATORY FORTIFIED BLANK (LFB) - An aliquot of reagent water to
which known quantities of the method analytes are added in the
laboratory. The LFB is analyzed exactly Tike a sample, and its
purpose is to determine whether the methodology is in control, and
whether the laboratory is capable of making accurate and precise
measurements at the required method detection limit.
LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
STOCK STANDARD SOLUTION -- A concentrated solution containing a
single certified standard that is a method analyte, or a
concentrated solution of a single analyte prepared in the laboratory
506-3
-------
with an assayed reference compound. Stock standard solutions are
used to prepare primary dilution standards.
3.6 PRIMARY DILUTION STANDARD SOLUTION — A solution of several analytes
prepared in the laboratory from stock standard solutions and diluted
as needed to prepare calibration solutions and other needed analyte
solutions.
3.7 CALIBRATION STANDARD (CAL) — a, solution prepared from the primary
dilution standard solution and stock standard solutions of the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration.
3.8 QUALITY CONTROL SAMPLE (QCS) — a sample matrix containing method
analytes or a solution of method analytes in a water miscible
solvent which is used to fortify reagent water or environmental
samples. The QCS is obtained from a source external to the
laboratory, and is used to check laboratory performance with
externally prepared test materials.
4. INTERFERENCES
4.1 Method interferences may be caused by contaminants in water,
solvents, reagents, glassware, and sample processing hardware.
These lead to discrete artifacts and/or elevated baselines in gas
chromatograms. All of these materials must be routinely
demonstrated to be free from interferences under the conditions of
the analysis by running laboratory reagent blanks (Sect. 10.2).
4.1.1 Phthalate esters are contaminants in many products found in
the laboratory. It is particularly important to avoid the
use of plastics because phthalates are commonly used as
plasticizers and are easily extracted from plastic materials.
Great care must be exercised to prevent contamination.
Exhaustive clean up of reagents and glassware must be
required to eliminate background phthalate that is not
derived from the sample.
4.1.2 Glassware must be scrupulously cleaned. Clean all glassware
as soon as possible after use by thoroughly rinsing with the
last solvent used. Follow by washing with hot water and
detergent and thorough rinsing with tap and reagent water.
Drain dry and heat in an oven or muffle furnace at 400°C for
1 hour. Do not heat volumetric glassware. Thorough rinsing
with acetone may be substituted for the heating. After
cooling, the glassware should be sealed with aluminum foil
and stored in a clean environment to prevent accumulation of
dust and other contaminants.
506-4
-------
4.1.3 The use of high purity reagents and solvents helps to
minimize interference problems. Purification of solvents by
distillation in an all glass system may be required.
WARNING: When a solvent is purified, stabilizers added by
the manufacturer are removed thus potentially making the
solvent hazardous. Also, when a solvent is purified,
preservatives added by the manufacturer are removed thus
potentially reducing the shelf-life.
4.2 Matrix interferences may be caused by contaminants that are co-
extracted from the sample. The extent of matrix interferences will
vary from source to source, dependent upon the nature and diversity
of the samples. Clean up procedures can be used to overcome many of
these interferences.
4.3 It is important that samples and working standards be contained in
the same solvent. The solvent for working standards must be the
same as the final solvent used in sample preparation. If this is
not the case, chromatographic comparability of standards to sample
may be affected.
SAFETY
5.1 The toxicity or carcinogenicity of each reagent used in this method
has not been precisely defined; however, each chemical compound must
be treated as a potential health hazard. Accordingly, exposure to
these chemicals must be reduced to the lowest possible level. The
laboratory is responsible for maintaining a current awareness file
of OSHA regulations regarding the safe handling of the chemicals
specified in this method. A reference file of material safety data
sheets should also be made available to all personnel involved in
the chemical analysis. Additional references to laboratory safety
are available and have been identified (5-7) for the information of
the analyst.
EQUIPMENT AND SUPPLIES (All specifications are suggested, catalog
numbers are included for illustration only.)
6.1 Sampling Equipment
. 6.1.1 Grab Sample Bottle—1-L or 1-qt amber glass, fitted with a
screw cap lined with Teflon. Protect samples from light if
amber bottles are not available. The bottle and cap liner
must be washed, rinsed with acetone or methylene chloride and
dried before use in order to minimize contamination. (See
'• , 4.1.1.)
6.2 Glassware
6.2.1 Separatory Funnel—2-L with Teflon stopcock.
506-5
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6.2.2 Drying Column—Chromatographic column-300 mm long x 10 mm ID,
with Teflon stopcock and coarse frit filter disc at bottom.
6.2.3 Concentrator Tube—Kuderna-Danish, 10 ml, graduated,
calibration must be checked at the volumes employed in the
test. Tight ground glass stopper is used to prevent
evaporation of extracts.
6.2.4 Evaporative Flask—Kuderna-Danish, 500 ml, attach to
concentrator tube with springs.
6.2.5 Snyder Column—Kuderna-Danish, three-ball macro size.
6.2.6 Snyder Column—Kuderna-Danish, 2 or 3 ball micro size.
6.2.7 Vials—10 to 15 ml, amber glass with Teflon-lined screw cap.
6.2.8 Boiling Chips—Approximately 10/40 mesh. Heat to 400°C for
30 min. or extract with methylene chloride in a Soxhlet
apparatus.
6.2.9 Flask, Erlenmeyer—250 ml.
6.2.10 Chromatography column similar to 6.2.2.
6.2.11 Pasteur Pipets (and Bulb).
6.2.12 Autosampler Vials—Equipped with Teflon-lined septum and
threaded or crimp top caps.
6.3 Water Bath—Heated (with concentric ring covers) capable of
temperature control (± 2°C). The water bath should be used in a
ventilating hood.
6.4 Balance—Analytical, capable of weighing accurately to nearest
0.0001 gm.
6.5 Gas Chromatograph—An analytical system complete with temperature
programmable GC fitted with split-splitless injection mode system,
suitable for use with capillary columns and all required accessory
syringes, analytical columns, gases, detector and stripchart
recorder. A data system for processing chromatographic data is
recommended.
6.5.1 Column, Fused Silica Capillary—DB-5 or equivalent, 30 m long
x 0.32 mm ID with a film thickness of 0.25 micron.
6.5.2 The alternate column, Fused Silica Capillary—30 m long x
0.32 mm ID with a film thickness of 0.25 micron, DB-1 or
equivalent.
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6.5.3 Detector— A high temperature photoionization detector
equipped for 10 electron volts (nominal voltage) and capable
of operating from 250°C to 350°C is required.
6.5.4 'An automatic injector system is suggested, but was not used
for the development of this method.
6.6 Vacuum source, capable of maintaining a vacuum of 10-15 mm Hg.
7. REAGENTS AND STANDARDS
7.1 Reagent Water -- Reagent water is defined as water in which an
interfering substance is not observed at the MDL of the parameters
of interest. Reagent water used to generate data in this method was
. distilled water obtained from the Millipore L/A-7044 system
comprised of prefiltration, organic adsorption, deionization and
Millipore filtration columnar units. Any system may be used if it
generates acceptable reagent water.
7.2 Acetone, hexane, methylene chloride, ethyl acetate, ethyl ether and
iso-octane — Pesticide quality or equivalent to distillation in
glass quality.
7.3 Sodium Sulfate—(ACS) Granular, anhydrous. Several levels of
purification may be required in order to reduce background phthalate
levels towards acceptance: 1) Heat 4 h at 400°C in a shallow tray,
2) Soxhlet extract with methylene chloride for 48 h.
7.4 Florisil—PR grade (60/100 mesh). To prepare for use, place 100 g
of Florisil into a 500-mL beaker and heat for approximately 16 h at
40°C. After heating transfer to a 500-mL reagent bottle. Tightly
seal-and cool to room temperature. When1cool, add 3 ml of reagent
water. Mix thoroughly by shaking or rolling for 10 min. and let it
stand for at least 2 h. Store in the dark in glass containers with
ground glass stoppers or foil-lined screw caps.
7.5 Sodium Chloride—(ACS) Granular. Heat 4 h at 400°C in a shallow
tray. When cool, keep in tightly sealed glass (not plastic) bottle.
This cleaning step is required to .minimize background contamination
associated with this reagent.
7.6 Ethyl Ether—(ACS) reagent grade.
7.7 Sodium Thiosulfate (Na2S203) —(ACS) reagent grade.
7.8 Alumina—Neutral activity Super I, W200 series (ICN Life Sciences
Group, No. 404583). To prepare for use, place 100 g of alumina into
a 500-mL beaker and heat for approximately 16 h at 400°C. After
heating transfer to a 500-mL reagent bottle. Tightly seal and cool
to room temperature. When cool, add 3 mL of reagent water. Mix
thoroughly by shaking or rolling for 10 min. and let it stand for at
least 2 h. Keep the bottle sealed tightly.
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7.9 Liquid-solid extraction (LSE) cartridges. Cartridges are inert non-
leaching plastic, for example polypropylene, or glass, and must not
contain plasticizers, such as phthalate esters or adipates, that
leach into methylene chloride. The cartridges are packed with about
1 gram of silica, or other inert inorganic support, whose surface is
modified by chemically bonded octadecyl (C18) groups. The packing
must have a narrow size distribution and must not leach organic
compounds into methylene chloride. One liter of water should pass
through the cartridge in about 2 hrs with the assistance of a slight
vacuum of about 13 cm (5 in.) of mercury. The extraction time
should not vary unreasonably among LSE cartridges.
7.10 Liquid-solid extraction disks, C-18, 47 mm. Disks are manufactured
with Teflon or other inert support and should contain very little
contamination.
7.11 Helium carrier gas, as contaminant free as possible.
7.12 Stock standard solutions (1.00 /^g/^L) - Stock standard solutions
can be prepared from pure standard materials or purchased as
certified solutions.
7.12.1 Prepare stock standard solutions by accurately weighing
about 0.0100 g of pure material. Dissolve the material in
isooctane and dilute to volume in a 10-mL volumetric flask.
Larger volumes can be used at the convenience of the analyst.
When compound purity is assayed to be 96% or greater, the
weight can be used without correction to calculate the
concentration of the stock standard. Commercially prepared
stock standards can be used at any concentration if they are
certified by the manufacturer or by an independent source.
7.12.2 Transfer the stock standard solutions into Teflon-sealed
screw-cap bottles. Store at 4°C and protect from light.
Stock standard solutions should be checked frequently for
signs of degradation or evaporation, especially just prior to
preparing calibration standards from them.
7.12.3 Stock standard solutions must be replaced after six months,
or sooner if comparison with check standards indicates a
problem. Butyl benzyl phthalate is especially vulnerable to
autoxidation.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 Grab samples must be collected in amber glass containers (Sect.6.1).
Conventional sampling practices should be followed (8,9); however,
the bottle must not be prerinsed with sample before collection.
8.2 SAMPLE PRESERVATION AND STORAGE
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8.2.1 For sample dechlorination, add 80 mg sodium thiosulfate to
the sample bottle at the sampling site or in the laboratory
before shipping to the sampling site.
8.2.2 After the sample is collected, seal the bottle and swirl the
sample until the thiosulfate is dissolved.
8.2.3 The samples must be iced or refrigerated at 4°C free from
light from the time of collection until extraction. Limited
holding studies have indicated that the analytes thus stored
are stable up to 14 days or longer. ,Analyte stability may be
affected by the matrix; therefore1, the analyst should verify
that the preservation technique is applicable to the
particular samples under study.
8.3 Extract Storage — Extracts should be stored at 4°C in absence of
light. A 14-day maximum extract storage time is recommended. The
analyst should verify appropriate extract holding times applicable
to the samples under study.
9. QUALITY CONTROL
9.1 Minimum quality control (QC) requirements are initial demonstration
of laboratory capability, analysis of laboratory reagent blanks,
laboratory fortified samples, laboratory fortified blanks, and QC
samples. A MDL for each analyte must also be determined.
Additional quality control practices are recommended.
9.2 Laboratory Reagent Blanks (LRB) Before processing any samples, the
analyst must demonstrate that all glassware and reagent
interferences are under control. Each time a set of samples is
extracted or reagents are changed, a LRB must be analyzed. If
within the retention time window of any analyte of interest the LRB
produces a peak that would prevent the determination of that analyte
using a known standard, determine the source of contamination and
eliminate the interference before processing samples.
9.3 Initial Demonstration of Capability.
9.3.1 Select a representative fortified concentration (about 10
times EDL or at a concentration in the middle of the
calibration range established in Section 10) for each
analyte. Prepare a primary dilution standard (in methanol)
containing each analyte at 1000 times selected concentration.
With a syringe, add 1 mL of the concentrate to each of four
to seven 1-L aliquots of reagent water, and analyze each
aliquot according to procedures beginning in Sect. 11.
9.3.2 For each analyte the mean recovery value for these samples
must fall in the range of R ± 30% using the values for R for
reagent water in Tables 3 or 4. The precision of these
measurements, expressed as RSD, must be 20% or less. For
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those compounds that meet the acceptance criteria,
performance is considered acceptable. For those compounds
that fail these criteria, this procedure must be repeated
using fresh replicate samples until satisfactory performance
has been demonstrated.
9.3.3 For each analyte, determine the MDL. Prepare a minimum of 7
LFBs at a low concentration. Fortification concentration in
Table 2 may be used as a guide, or use calibration data
obtained in Section 10 to estimate a concentration for each
analyte that will produce a peak with a 3-5 times signal to
noise response. Extract and analyze each replicate according
to Sections 11 and 12. It is recommended that these LFBs be
prepared and analyzed over a period of several days, so that
day to day variations are reflected in precision
measurements. Calculate mean recovery and standard deviation
for each analyte. Use the standard deviation and the equation
given in Section 13 to calculate the MDL.
9.3.4 The initial demonstration of capability is used primarily to
preclude a laboratory from analyzing unknown samples via a
new, unfamiliar method prior to obtaining some experience
with it. It is expected that as laboratory personnel gain
experience with this method the quality of data will improve
beyond those required here.
9.4 The analyst is permitted to modify GC columns, GC conditions,
concentration techniques (i.e. evaporation techniques), internal
standards or surrogate compounds. Each time such method
modifications are made, the analyst must repeat the procedures in
Sect. 9.3.
9.5 Assessing Laboratory Performance - Laboratory Fortified Blank
9.5.1 The laboratory must analyze at least one laboratory fortified
blank (LFB) sample with every twenty samples or one per
sample set (all samples extracted within a 24-h period)
whichever is greater. Ideally, the fortified concentration
of each analyte in the LFB should be the same concentration
selected in Section 9.3.1. Calculate accuracy as percent
recovery (X-)- If the recovery of any analyte falls outside
the control limits (see Sect. 9.5.2), that analyte is judged
out of control, and the source of the problem should be
identified and resolved before continuing analyses.
9.5.2 Until sufficient data become available from within their own
laboratory, usually a minimum of results from 20 to 30
analyses, the laboratory should assess laboratory performance
against the control limits in Sect. 9,3.2 that are derived
from the data in Table 2. When sufficient internal
performance data becomes available, develop control limits
from the mean percent recovery (X) and standard deviation (S)
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of the percent recovery. These data are used to establish
upper and lower control limits as follows:
UPPER CONTROL LIMIT = X + 3S *
LOWER CONTROL LIMIT = X - 3S
After each five to ten new recovery measurements, new control
limits should be calculated using only the most recent 20-30
data points. These calculated control limits should not
exceed those established in Sect. 9.3.2.
9.6 Assessing Analyte Recovery — Laboratory Fortified Sample Matrix
9.6.1 The laboratory must fortify each analyte to a minimum of 10%
of the routine samples or one fortified sample per set,
whichever is greater. The fortified concentration should not
be less than the background concentration of the sample
selected for fortifying. Ideally, this concentration should
be the same as that used for the laboratory fortified blank
(Sect. 9.5). Over time, samples from all routine sample
sources should be fortified.
9.6.2 Calculate the accuracy as percent recovery, R, for each
analyte, corrected for background concentrations measured in
the unfortified sample. For each analyte the mean recovery
value for these samples must fall in the range of R ± 35%
using the values for R for reagent water in Tables 3 or 4.
9.6.3 If the recovery of any such analyte falls outside the
designated range, and the laboratory performance for that
analyte is shown to be in control (Sect. 9.5), the recovery
problem encountered with the dosed sample is judged to be
matrix related, not system related. The result for that
analyte in the unfortified sample is labeled suspect/matrix
to inform the data user that the results are suspect due to
matrix effects.
QUALITY CONTROL SAMPLES (QCS) - Each quarter, the laboratory should
analyze one or more QCS (if available). If criteria provided with
the QCS are not met, corrective action should be taken and
documented.
The laboratory may adopt additional quality control practices for
use with this method. The specific practices that are most
productive depend upon the needs of the laboratory and the nature
of the samples. For example, field or laboratory duplicates may be
analyzed to assess the precision of the environmental measurements.
10. CALIBRATION AND STANDARDIZATION
10.1 Establish gas chromatograph operating conditions equivalent to those
given in Table 1. The gas chromatographic system is calibrated
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9.7
9.8
-------
using the external standard technique. Calibration standards must
be prepared in the same solvent as the final sample extract. This
will vary with the extraction option chosen (hexane for LLE,
methylene chloride for LSE-cartridge, and acetonitrile for LSE-
disk). Sect. 10.2.1 details the hexane option as an example.
10.2 External standard calibration procedure:
10.2.1 Prepare calibration standards at a minimum of three
concentration levels for each analyte of interest by adding
volumes of one or more stock standards to a volumetric flask
and diluting to volume with n-hexane. Guidance on the number
of standards is as follows: A minimum of three calibration
standards are required to calibrate a range of a factor of 20
in concentration. For a factor of 50 use at least four
standards, and for a factor of 100 at least five standards.
One calibration standard should contain each analyte of
concern at a concentration 2 to 10 times greater than the
method detection limit for that compound. The other
calibration standards should contain each analyte of concern
at concentrations that define the range of the sample analyte
concentrations or should define the working range of the
detector.
10.2.2 Using injections of 1 to 2 jLtL, analyze each calibration
standard according to Sect. 11.5 and tabulate peak height or
area responses against the mass injected. The results can be
used to prepare a calibration curve for each compound.
Alternatively, if the ratio of response to amount injected
(calibration factor) is a constant over the working range
(<20% relative standard deviation, RSD), linearity through
the origin can be assumed and the average ratio or
calibration factor can be used in place of a calibration
curve.
10.2.3 The working calibration curve or calibration factor must be
verified on each working day by the measurement of a minimum
of two calibration check standards, one at the beginning and
one at the end of the analysis day. These check standards
should be at two different concentration levels to verify the
calibration curve. For extended periods of analysis (greater
than 8 hrs.), it is strongly recommended that check standards
be interspersed with samples at regular intervals during the
course of the analyses. If the response for any analyte
varies from the predicted response by more than ±20%, the
test must be repeated using a fresh calibration standard. If
the results still do not agree, generate a new calibration
curve. For those analytes that failed the calibration
verification, results from field samples analyzed since the
last passing calibration should be considered suspect.
Reanalyze sample extracts for these analytes after acceptable
calibration is restored.
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11. PROCEDURE
11.1 LIQUID-LIQUID EXTRACTION
11.1.1 Mark the water meniscus on the side of the sample bottle for
later determination of sample volume. Pour the entire sample
into a 2-L separatory funnel containing 50 g of NaCl.
11.1.2 Add 60 ml CH2C12( to the sample bottle. Seal, and shake
.gently to rinse'the inner walls of the bottle. Transfer the
solvent to the separatory funnel. Extract the sample by
shaking the funnel for 2 min with initial and periodic
venting to release excess pressure. Allow the organic layer
to separate for a minimum of 10 min from the water phase. If
the emulsion interface between layers is more than one-third
the volume of the solvent layer, the analyst must employ
mechanical techniques to complete the phase separation. The
optimum technique depends upon the sample, but may include
stirring, filtration of the emulsion through glass wool,
centrifugation, or other physical methods. Collect the
solvent extract in a 250-mL Erlenmeyer flask.
11.1.3 Add a second 60-mL volume of methylene chloride to the sample
bottle and repeat the extraction procedure a second time,-
combining the extracts in the Erlenmeyer flask. Perform a
third extraction in the same manner. Then extract with 40-mL
of hexane, which extract (top phase) is added to the total.
11.1.4 Assemble a Kuderna-Danish (K-D) concentrator by attaching a
10-mL concentrator tube to a 500-mL evaporative flask. Other
concentration devices or techniques may be used in place of
the K-D concentrator, provided the concentration factor
attained in 11.1.6 - 11.1.8 is achieved without loss of
analytes.
11.1.5 Pour the combined extract through a drying column (6.2.2)
containing about 10 cm of prerinsed .anhydrous sodium sulfate,
and collect the extract in the K-D concentrator. Rinse the
Erlenmeyer flask and column with 20 to 30 mL of methylene
chloride to complete the quantitative transfer.
11.1.6 Add one or two clean boiling chips to the evaporative flask
and attach a three-ball Snyder column. Prewet the Snyder
column by adding about 1 mL of methylene chloride to the top.
Place the K-D apparatus on a hot water bath (60 to 65°C) so
that the concentrator tube is partially immersed in the hot
water, and the entire lower rounded surface of the flask is
bathed with hot vapor. Adjust the vertical position of the
apparatus and the water temperature as required to complete
the concentration in 40 min. At the proper rate of
distillation the balls of the column will actively chatter
but the chambers will not flood with condensed solvent. When
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the apparent volume of liquid reaches approximately 7 ml,
remove the K-D apparatus and allow it to drain and cool for
at least 10 min.
11.1.7 Increase the temperature of the hot water bath to about 85°C.
Remove the Snyder column, rinse the column and the 500-mL
evaporative flask with 1 - 2 ml of hexane. Replace with a
micro column and evaporative flask. Concentrate the extract
as in Sect. 11.1.6 to 0.5 - 1 ml_. The elapsed time of
concentration should be approximately 15 min.
11.1.8 Remove the micro Snyder column and rinse the column by
flushing with hexane using a 5-mL syringe. Concentrate to a
volume of 1 ml by purging the liquid surface with a gentle
flow of nitrogen or clean air. If an autosampler is to be
used, transfer the extract to an autosampler vial with a
Pasteur pipet. Seal the vial with a threaded or crimp top
cap. Store in refrigerator if further processing will not be
performed. If the sample extract requires no further
cleanup, proceed with gas chromatographic analysis (Sect.
11.5). If the sample requires further cleanup, proceed to
Sect. 11.4.
11.1.9 Determine the original sample volume by refilling the sample
bottle to the mark and transferring the liquid to a 1000-mL
graduated cylinder. Record the sample volume to the nearest
5 ml.
11.2 LIQUID-SOLID EXTRACTION - CARTRIDGE OPTION
11.2.1 This method is applicable to a wide range of organic
compounds that are efficiently partitioned from the water
sample onto a C18 organic phase chemically bonded to a solid
inorganic matrix, and are sufficiently volatile and thermally
stable for gas chromatography (10). See Section 11.3 for the
disk option procedure. Particulate bound organic matter will
not be partitioned, and more than trace levels of
particulates in the water may disrupt the partitioning
process. Single laboratory accuracy and precision data have
been determined at a single concentration for the analytes
listed in Sect. 1.1 fortified into reagent water and raw
source water.
11.2.2 Set up the extraction apparatus shown in Figure 1A. An
automated extraction system may also be used. The reservoir
is not required, but recommended for convenient operation.
Water drains from the reservoir through the LSE cartridge and
into a syringe needle which is inserted through a rubber
stopper into the suction flask. A slight vacuum of 13 cm (5
in.) of mercury is used during all operations with the
apparatus. With this extraction apparatus, sample elution
requires approximately 2 hours. Acceptable new cartridge and
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extraction, disk technology have recently become available,
which allow significantly faster elution rates.
11.2.3 Mark the water meniscus on the side of the sample bottle
(approximately 1 liter) for later determination of sample
volume. Pour the water sample into the 2-1 separatory funnel
with the stopcock closed.
11.2.4 Flush each cartridge with two 10 ml aliquots of methylene
chloride, followed by two 10 mL aliquots of methanol, letting
the cartridge drain dry after each flush. These solvent
flushes may be accomplished by adding the solvents directly
to the solvent reservoir in Figure 1A. Add 10-mL of reagent
water to the solvent reservoir, but before the reagent water
level drops below the top edge of the packing in the LSE
cartridge, open the stopcock of the separatory funnel and
, begin adding sample water to the solvent reservoir. Close
the stopcock when an adequate amount of sample is in the
reservoir. . '
11.2.5 Periodically open the stopcock and drain a portion of the
sample water into the solvent reservoir. The water sample
will drain into the cartridge, and from the exit into the
suction flask. Maintain the packing material in the
cartridge immersed in water at all times. After all of the
sample has passed .through the LSE cartridge, wash the
separatory funnel and cartridge with 10 ml of reagent water,
and draw air through the cartridge for about 10 min.
11.2.6 Transfer the 125-mL solvent reservoir and LSE cartridge (from
Figure 1A) to the elution apparatus (Figure IB). The same
125 mL solvent reservoir is used for both apparatus. Wash
the 2-liter separatory funnel with 5 mL of methylene chloride
and collect the washings. Close the stopcock on the 100-mL
separatory funnel of the elution apparatus, add the washings
to the reservoir and enough additional methylene chloride to
bring the volume back up to 5 mL and elute the LSE cartridge.
Elute the LSE cartridge with an additional 5 mL of methylene
chloride (10-mL total). A small amount of nitrogen positive
pressure may be used to elute the cartridge. Small amounts of
residual water from the LSE cartridge will form an immiscible
layer with the methylene chloride in the 100-mL separatory
funnel. Open the stopcock and allow the methylene chloride
to pass through the drying column packed with anhydrous
sodium sulfate (1-in) and into the collection vial. Do not
allow the water layer to enter the drying column. Remove the
100 mL separatory funnel and wash the drying column with 2 mL
of methylene chloride. Add this to the extract. Concentrate
the extract to 1 mL under a gentle stream:of nitrogen. The
extract is now ready for gas chrbmatqgraphy (Sect. 11.4) or
additional cleanup (Sect. 11.3).
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11.3 LIQUID-SOLID EXTRACTION - DISK OPTION
11.3.1 Preparation of disks.
11.3.1.1 Insert the disk into the 47 mm filter apparatus.
Wash the disk with 5 mL methylene chloride (MeCl2)
by adding the MeC12 to the disk, pulling about half
through the disk and allowing it to soak the disk
for about a minute, then pulling the remaining MeCl2
through the disk. With the vacuum on, pull air
through the disk for a minute.
11.3.1.2 Pre-wet the disk with 5 mL methanol (MeOH) by adding
the MeOH to the disk, pulling about half through the
disk and allowing it to soak for about a minute,
then pulling most of the remaining MeOH through. A
layer of MeOH must be left on the surface of the
disk, which shouldn't be allowed to go dry from this
point until the end of the sample extraction. THIS
IS A CRITICAL STEP FOR A UNIFORM FLOW AND GOOD
RECOVERY.
11.3.1.3 Rinse the disk with 5 mL reagent water by adding the
water to the disk and pulling most through, again
leaving a layer on the surface of the disk.
11.3.2 Add 5 mL MeOH per liter of water sample. Mix well.
11.3.3 Add the water sample to the reservoir'and turn 'on the vacuum
to begin the filtration. Full aspirator vacuum may be used.
Particulate-free water may filter in as little as 10 minutes
or less. Filter the entire sample, draining as much water
from the sample container as possible.
11.3.4 Remove the filtration top from the vacuum flask, but don't
disassemble the reservoir and fritted base. Empty the water
from the flask and insert a suitable sample tube to contain
the eluant. The only constraint on the sample tube is that
it fit around the drip tip of the fritted base. Reassemble
the apparatus.
Add 5 mL of acetonitrile (CH3CN) to rinse the sample bottle.
Allow the CH,CN to settle to the bottom of the bottle and
transfer to the disk with a dispo-pipet, rinsing the sides of
the glass filtration reservoir in the process. Pull about
half of the CH3CN through the disk, release the vacuum, and
allow the disk to soak for a minute. Pull the remaining
CH3CN through the disk.
Repeat the above step twice, using MeCl, instead of CH3CN.
Pour the combined eluates thru a small funnel with filter
paper containing 3 grams of anhydrous sodium sulfate. Rinse
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the test tube and sodium sulfate with two 5 mL portions of
MeCl2. Collect the filtrate in a concentrator tube.
11.3.5 With the concentrator tube in a 28°C heating block,
evaporate the eluate with a stream of N2 to 0.5 ml.'
11.4 EXTRACT CLEANUP - Cleanup procedures may not be necessary for a
relatively clean sample matrix, such as most drinking waters. If
particular circumstances demand the use of a cleanup procedure, the
analyst may use either procedure below or any other appropriate
procedure. However, the analyst first must demonstrate that the
requirements of Sect. 9 can be met using the method as revised to
incorporate the cleanup procedure.
11.4.1 Florisil column cleanup for phthalate esters:
11.4.1.1 Place 10 g of Florisil (see 7.4) into a
chromatographic column. Tap the column to settle
the Florisil and add 1 cm of anhydrous sodium
sulfate to the top.
11.4.1.2 Preelute the column with 40 mL of hexane. Discard
the eluate and just prior to exposure of the sodium
sulfate layer to the air, quantitatively transfer
the sample extract (11.1.8.or 11.2.6) onto the
column, using an additional 2 mL of hexane to
complete the transfer. Just prior to exposure of
the sodium sulfate layer to the air, add 40 mL of
hexane and continue the elution of the column.
Discard this hexane eluate.
11.4.1.3 Next, elute the column with 100 mL of 20% ethyl
ether in hexane (V/V) into a 500-mL K-D flask
equipped with a 10-mL concentrator tube. Elute the
column at a rate of about 2 mL/min for all
fractions. Concentrate the collected fraction as in
Section 11.1. No solvent exchange is necessary.
Adjust the volume of the cleaned extract to 1 mL in
the concentrator tube and analyze by gas
chromatography.
11.4.2 Alumina column cleanup for phthalate esters:
11.4.2.1 Place 10 g of alumina into a chromatographic column-
Tap the column to settle the alumina and add 1 cm of
anhydrous sodium sulfate to the top.
11.4.2.2 Preelute the column with 40 mL of hexane. The rate
for all elutions should be about 2 mL/min. Discard
the eluate and just prior to exposure of the sodium
sulfate layer to the air, quantitatively transfer
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the sample extract (Sect. 11.1.8 or 11.2.6) onto the
column, using an additional 2 mL of hexane to
complete the transfer. Just prior to exposure of
the sodium sulfate layer to the air, add 35 ml of
hexane and continue the elution of the column.
Discard this.hexane eluate.
11.4.2.3 Next, elute the column with 140 mL of 20% ethyl
ether in hexane (V/V) intq a 500-mL K-D flask
equipped with a 10-mL concentrator tube. Concentrate
the collected fraction as in Section 11.1. No
solvent exchange is necessary. Adjust the volume of
the cleaned extract to 1 ml in the concentrator tube
and analyze by gas chromatography.
11.5 GAS CHROMATOGRAPHY
11.5.1 Table 1 summarizes the recommended operating conditions for
the gas chrpmatograph. Included are retention data for the
primary and confirmation columns. Other capillary columns,
chromatographic conditions may be used if the requirements of
Section 9 are met.
11.5.2 Calibrate the system daily as described in Sect. 10.'
11.5.3 Inject 1 to 2 /iL of the sample extract or standard into the
gas chromatograph. Smaller (1.0 /til) volumes may be injected
if automatic devices are employed. For optimum
reproducibility, an autoinjector is recommended.
11.5.4 Identify the analytes in the sample by comparing the
retention times of the peaks in the sample chromatogram with
those of the peaks in standard chromatograms. The width of
the retention time window used to make identifications should
be based upon measurements of actual retention time
variations of standards over the course of a day. Three
times the standard deviation of a retention time for a
compound can be used to calculate a suggested window size;
however, the experience of the analyst should weigh heavily
in the interpretation of chromatograms.
11.5.5 If the response ,for a peak exceeds the working range of the
system, dilute the extract and reanalyze.
11.5.6 If the measurement of the peak response is prevented by the
presence of interferences, further cleanup is required.
11.5.7 The calibration curves should be linear over the range of
concentrations in Tables 2-5. Do not extrapolate beyond the
calibration range established in Section 10. If analyte
response is too high, dilute the extract and reanalyze.
506-18
-------
12. DATA ANALYSIS AND CALCULATIONS
12.1 Calculate the amount of material injected from the peak response
using the multi-point calibration curve or calibration factor
determined in Section 10.2.2. Do "not use the daily calibration
verification standard to quantitate method analytes in samples.
concentration in the sample can be calculated from Equation 2.
The
Equation 2.
where:
Concentration (Mg/L) = 4§*£U_
A = Amount of material injected (ng).
V,. = Volume of extract injected (fj.1).
Vt = Volume of total extract (jiL).
Vs = Volume of water extracted (mL).
12.2 Report results in Aig/L without correction for recovery data,
QC data obtained should be reported with the sample results.
13. METHOD PERFORMANCE
All
13.1 Single laboratory accuracy and precision data were obtained by
replicate liquid-liquid extraction analyses of reagent water
fortified at two sets of concentrations of method analytes. The
data are given in Tables 2 and 3. Accuracy and precision data by
liquid-solid extraction of reagent water fortified at a single
concentration are given in Table 4. Finally, Method validation data
obtained by the analyses of fortified tap water and raw source water
are given in Tables 5-7.
13.2 Demonstrated MDLs are given in Table 2.
following equations were used:
To calculate MDLs, the
MDL = S t
(n-1,1-alpha = 0.99)
where:
14.
t(n-i i-aipha = o 991 " Student's t value for the 99%
confidence level with n-1 degrees of freedom
n = number of replicates
S = standard deviation of replicate analyses.
POLLUTION PREVENTION
14.1 One option of this method utilizes the new liquid-solid extraction
(LSE) technology to remove the analytes from water. It requires the
506-19
-------
use of very small volumes of organic solvent and very small
quantities of pure analytes, thereby eliminating the potential
hazards to both the analyst and the environment. The other option
in this method uses significant volumes of organic solvents. It is
highly recommended that laboratories use solvent recovery systems to
recover used solvent as sample extracts are being concentrated.
Recovered solvents should be recycled or properly disposed of.
14.2 For information about pollution prevention that may be applicable to
laboratory operations, consult "Less Is Better: Laboratory Chemical
Management for Waste Reduction" available from the American Chemical
Society's Department of Government Relations and Science Policy,
1155 16th Street N.W., Washington, D.C., 20036.
15. WASTE MANAGEMENT
15.1 It is the laboratory's responsibility to comply with all federal,
state, and local regulations governing waste management,
particularly the hazardous waste identification rules and land
disposal restrictions. The laboratory using this method has the
responsibility to protect the air, water, and land by minimizing and
controlling all releases from fume hoods and bench operations.
Compliance is also required with any sewage.discharge permits and
regulations. For further information on waste management, consult
"The Waste Management Manual for Laboratory Personnel," also
available from the American Chemical Society at the address in Sect.
14.2.
16. REFERENCES
1. Glaser, J.V., D.L. Foerst, G.D. McKee, S.A. Quave, and W.L. Budde,
"Trace Analysis for Waste Waters," Environ. Sci. Techno!. 15, 1426,
1981.
2. "Determination of Phthalates in Industrial and Municipal
Wastewaters," EPA-600/4-81-063, U.S. Environmental Protection
Agency, Environmental Monitoring and Support Laboratory, Cincinnati,
Ohio 45268, October 1981.
3. Giam, C.S., Chan, H.S. and Nef, G.S. "Sensitive Method for
Determination of Phthalate Ester Plasticizers in Open-Ocean Biota
Samples," Anal. Chem.. 47, 2225 (1975).
4. Giam, C.S., and Chan, H.S. "Control of Blanks in the Analysis of
Phthalates in Air and Ocean Biota Samples," U.S. National Bureau of
Standards, Special Publication 442, pp. 701-708, 1976.
5. "Carcinogens - Working with Carcinogens," Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77-206, August 1977.
506-20
-------
6. "OSHA Safety and Health Standards, General Industry," (29 CFR 1910),
Occupational Safety and Health Administration, OSHA 2206 (Revised,
January 1976). ,
7. "Safety in Academic Chemistry Laboratories," American Chemical
Society Publication, Committee on Chemical Safety, 3rd Edition
1979.
8. ASTM Annual Book of Standards, Part 31, D3694-78. "Standard
Practices for Preparation of Sample Containers and for Preservation
of Organic Constituents," American Society for Testing and
Materials, Philadelphia.
9. ASTM Annual Book of Standards^ Part 31, D3370. "Standard Practices
for Sampling Water," American Society for Testing and Materials,
Philadelphia.
10. Munch, J. W., "Method 525.2-Determination of Organic Compounds in
Drinking Water by Liquid-Solid Extraction and Capillary Column
Chromatography/ Mass Spectrometry" in Methods for the Determination
of Organic Compounds in Drinking Water; Supplement 3 (1995).
USEPA, National Exposure Research Laboratory, Cincinnati, Ohio
45268.
506-21
-------
17. TABLES. DIAGRAMS. FLOWCHARTS.
VALIDATION DATA
TABLE 1. RETENTION DATA AND CHROMATOGRAPHIC CONDITIONS
Parameter
Dimethyl phthalate
Di ethyl phthalate
Di-n-butyl phthalate
Butyl benzyl phthalate
Bis(2-ethylhexyl) adipate
Bis(2-ethylhexyl) phthalate
Di-n-octyl phthalate
Retention
(min)
Column 1
17.23
20.29
27.57
34.19
34.85
37.51
41.77
Time
Column 2
,17.89
21.13
28.67
35.34
36.76
39.58
44.44
Column 1: DB-5, fused silica capillary, 30 m x 0.32 mm I.D.,
0.25 micron film thickness, Helium linear velocity = 30 cm/s.
Column 2: DB-1, fused silica capillary, 30 m x 0.32 mm I.D.,
0.25 micron film thickness, Helium linear velocity = 30 cm/s.
Chromatographic Conditions:
Injector temperature = 295°C
Detector temperature = 295°C
Program - 1 min hold at 60°C,
6°C/min to 260°C, 10 min hold.
Splitless injection with 45 s
delay
506-22
-------
TABLE 2. ACCURACY, PRECISION, AND METHOD DETECTION LIMIT DATA FROM
SIX LIQUID-LIQUID EXTRACTION ANALYSES OF FORTIFIED REAGENT WATER
i
Analyte
Dimethyl phthalate
Diethyl phthalate
Di-n-butyl phthalate
Butyl benzyl phthalate
Bis(2-ethylhexyl) adipate
Bis(2-ethylhexyl) phthalate
Di-n-octyl phthalate
True
Cone.
M9/L
2.02
1.51
2.62
6.00
6.03
5.62
17.18
Mean
Meas.
Cone.
M9/L
1.42
1.16
1.78
3.27
• 3.94
2.92
7.96
.Mean
Std. Accuracy
Dev. % of True
M9/L Cone.
0.38
0.28
0.41
0.89
1.44
0.75
2.14
70.3
76.8
67.9
54.5
65.3
52.0
46.3
MDL
M9/L
1.14
0.84
1.23
2.67
11.82
2.25
6.42
506-23
-------
TABLE 3. ACCURACY AND PRECISION DATA FROM SEVEN LIQUID-LIQUID
EXTRACTION ANALYSES OF FORTIFIED REAGENT WATER
True
Concentration
Analyte M9/L
Dimethyl phthalate
Di ethyl phthalate
Di-n-butyl phthalate
Butyl benzyl phthalate
Bis(Z-ethylhexyl) adipate
Bis(2-ethylhexyl) phthalate
Di-n-octyl phthalate
15
15
15
15
30
30
30
Relative
Mean Accuracy Standard
% of True Deviation
Concentration %
73 16
71 16
68 15
71 15
69 18
67 21
.62 23
506-24
-------
TABLE 4. ACCURACY AND PRECISION DATA FROM SIX LIQUID-SOLID
EXTRACTION ANALYSES OF FORTIFIED REAGENT WATER
True
Concentration
Analyte Mg/L
Dimethyl phthalate
Diethyl phthalate
Di-n-butyl phthalate
Butyl benzyl phthalate
Bis(2-ethylhexyl) adipate
Bis(2-ethylhexyl) phthalate
Di-n-octyl phthalate
15
15
15
15
30
30
30
Relative
Mean Accuracy Standard
% of True Deviation
Concentration %
74
85
74
72
84
101
85
11 .
10
11
14
11
13
13
506-25
-------
TABLE 5. ACCURACY AND PRECISION DATA FROM SIX LIQUID-LIQUID
EXTRACTION ANALYSES OF FORTIFIED TAP WATER
Analyte
True
Concentration
M'9/L
Relative
Mean Accuracy Standard
% of True Deviation
Concentration %
Dimethyl phthalate
Di ethyl phthalate
Di-n-butyl phthalate
Butyl benzyl phthalate
Bis(2-ethylhexyl) adipate
Bis(Z-ethylhexyl) phthalate
Di-n-octyl phthalate
5
5
5 '.
5
5
5
5
103
106
94
93
87
93
72
10.0 .
10.0
6.8
9.1
12.0
4.9
26.0
506-26
-------
TABLE 6. ACCURACY AND PRECISION DATA FROM SIX LIQUID-LIQUID
EXTRACTION ANALYSES OF FORTIFIED RAW SOURCE WATER
True
Concentration
Analyte ^g/L
Dimethyl phthalate
Di ethyl phthalate
Di-n-butyl phthalate
Butyl benzyl phthalate
Bis(2-ethylhexyl) adipate
Bis(2-ethylhexyl) phthalate
Di-n-octyl phthalate
' 5
5
5
5
5
5
5
Relative
Mean Accuracy Standard
% of True Deviation
Concentration %
59
78
99
72
115
91
54
51
45
29
23
32
35
24
506-27
-------
TABLE 7. ACCURACY AND PRECISION DATA FROM SIX LIQUID-SOLID
EXTRACTION ANALYSES OF FORTIFIED RAW SOURCE WATER
True
Concentration
Analyte M9/L
Dimethyl phthalate
Di ethyl phthalate
Di-n-butyl phthalate
Butyl benzyl phthalate
Bis(2-ethylhexyl) adipate
Bis(Z-ethylhexyl) phthalate
Di-n-octyl phthalate
5
5
5
5
5
5
5
Mean Accuracy
% of True
Concentration
110
111
95
82
65
60
53
Standard
Deviation
%
20
32
30
20
24
21
15
506-28
-------
2 Uttr
separator^
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125ml
solvent
reservoir
ground gfass T 14/3 5
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,
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ncvu i
506-29
©. E!ut!on apparatus
-------
t3
oc
11 h n 11111111111111 m i -n n 11111111 n n H it 11 n iu J i u > T i»11 * 11 T 11 * i
TIME (MIN.)
Peaks obtained by Injecting S n9 for the 1st, 2nd, 4th and 5th
coopounds, 10 ng for tht 6th, 7th thd 8th ewnpounds, ind 2.5 ng
for the 3rd compound. (Table 1)
F16URC 2
506-30
-------
METHOD 507. DETERMINATION OF NITROGEN- AND PHOSPHORUS-CONTAINING
PESTICIDES IN WATER BY GAS CHROMATOGRAPHY WITH A NITROGEN-
PHOSPHORUS DETECTOR
Revision 2.1
Edited by J.W. Munch (1995)
T. Engel (Battelle Columbus Laboratories) and D. Munch (U.S. EPA, Office of
Water), National Pesticide Survey Method 1, Revision 1.0 (1987)
R. L. Graves - Method 507, Revision 2.0 (1989)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
507-1
-------
METHOD 507
DETERMINATION OF NITR06EN-AND PHOSPHORUS-CONTAINING PESTICIDES IN WATER
BY GAS CHROMATOGRAPHY WITH A NITROGEN-PHOSPHORUS DETECTOR
1. SCOPE AND APPLICATION
1.1 This is a gas chromatographic (GC) method applicable to the
determination of certain nitrogen- and phosphorus-containing
pesticides in ground water and finished drinking water. The
following compounds can be determined using this method:
Analvte
Alachlor
Ametryn
Atraton
Atrazine
Bromacil
Butachlor
Butyl ate
Carboxin
Chlorpropham
Cycloate
Diazinon(a)*
Dichlorvos
Diphenamid
Disulfoton*
Disulfoton sulfone*
Disulfoton sulfoxide(a)'
EPIC
Ethoprop
Fenamiphos
Fenarimol
Fluridone
Hexazinone
Merphos*
Methyl paraoxon
Metolachlor
Metribuzin
Mevinphos
MGK 264
Molinate
Napropamide
Norflurazon
Pebulate
Prometon
Prometryn
Pronamide(a)*
Propazine
Simazine
Simetryn
Stirofos
Tebuthiuron
Chemical Abstract Services
Registry Number
15972-
834-
1610-
1912-
314-
23184-
2008-
5234-
101-
1134-
333-
62-
957-
298-
2497-
2497-
759-
13194-
22224-
60168-
59756-
51235-
150-
950-
51218-
21087-
7786-
113-
2212-
15299-
27314-
1114-
1610-
7287-
23950-
139-
122-
1014-
22248-
34014-
60-8
12-8
17-9
24-9
40-9
66-9
41-5
68-5
21-3
23-2
41-5
73-7
51-7
04-4
06-5
07-6
94-4
48-4
92-6
88-9
60-4
04-2
50-5
35-6
45-2
64-9
34-7
48-4
67-1
99-7
13-2
71-2
18-0
19-6
58-5
40-2
34-9
70-6
79-9
18-1
507-2
-------
Terbacil 5902-51-2
Terbufos(a)* 13071-79-9
Terbutryn 886-50-0
Triademefon 43121-43-3
Tricyclazole . 41814-78-2
Vernolate 1929-77-7
(a) Compound exhibits aqueous instability. Samples for which this
compound is an analyte of interest must be extracted
immediately (Sections 11.1 through 11.3).
* These compounds are only qualitatively identified. These
compounds are not quantitated because control over precision
has not been accomplished.
1.2 This method has been validated in a single laboratory and estimated
detection limits (EDLs) and method detection limits (MDLs) have been
determined for the analytes above (Sect. 13). Observed detection
limits may vary among waters, depending upon the nature of
interferences in the sample matrix and the specific instrumentation
used.
1.3 This method is restricted to use by or under the supervision of
analysts experienced in the use of GC and in the interpretation of
'gas chromatograms. Each analyst must demonstrate the ability to
generate acceptable results with this method using the procedure
described in Sect. 9.
1.4 Analytes that are not separated chromatographically, i.e., analytes
which have very similar retention times, cannot be individually
identified and measured in the same calibration mixture or water
sample unless an alternative technique for identification and.
quantitation exist (Section 11.5).
1.5 When this method is used to analyze unfamiliar samples for any or
all of the analytes above, analyte identifications should be
confirmed by at least one additional qualitative technique.
2. SUMMARY OF METHOD
2.1 A measured volume of sample of approximately 1 L is extracted with
methylene ch'loride by shaking in a separatory funnel or mechanical
tumbling in a bottle. The methylene chloride extract is isolated,
dried and concentrated to a volume of 5 ml during a solvent exchange
to methyl tert-butyl ether (MTBE). Chromatographic conditions are
described which permit the separation and measurement of the
analytes in the extract by Capillary Column GC with a nitrogen-
phosphorus detector (NPD).
3. DEFINITIONS
3.1 INTERNAL STANDARD — A pure analyte(s) added to a solution in known
amount(s) and used to measure the relative responses of other method
analytes and surrogates that are components of the same solution.
The internal standard must be an analyte that is not a sample
component.
507-3
-------
3.2 SURROGATE ANALYTE — A pure analyte(s), which is extremely unlikely
to be found in any sample, and which is added to a sample aliquot in
known amount(s) before extraction and is measured with the same
procedures used to measure other sample components. The purpose of
a surrogate analyte is to monitor method performance with each
sample.
3.3 LABORATORY DUPLICATES (LD1 and LD2) — Two sample aliquots taken in
the analytical laboratory and analyzed separately with Identical
procedures. Analyses of LD1 and LD2 give a measure of the precision
associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures.
3.4 FIELD DUPLICATES (FD1 and FD2) —Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage,"as well as with
laboratory procedures.
3.5 LABORATORY REAGENT BLANK (LRB) — An aliquot of reagent water that
is treated exactly as a sample including exposure to all' glassware,-
equipment, solvents, reagents, internal standards, and surrogates
that are used with other samples. The LRB is used to determine if
method analytes or other interferences are present in the laboratory
environment, the reagents, or the apparatus.
3.6 FIELD REAGENT BLANK (FRB) — Reagent water placed in a sample
container in the laboratory and treated as a sample in all respects,
including exposure to sampling site conditions, storage, preserva-
tion and all analytical procedures. The purpose of the FRB is to
determine if method analytes or other1interferences are present in
the field environment.
3.7 LABORATORY PERFORMANCE CHECK SOLUTION (LPC) — A solution of method
analytes, surrogate compounds, and internal standards used to
evaluate the performance of the instrument system with respect to a
defined set of method criteria.
3.8 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water to
which known quantities of the method analytes are added in the
laboratory. The LFB is analyzed exactly like a sample, and its
purpose is to determine whether the methodology is in control, and
whether the laboratory is capable of making accurate and precise
measurements at the required method detection limit.
3.9 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
507-4
-------
3.10 STOCK STANDARD SOLUTION — A concentrated solution containing a
single certified standard that is a method analyte, or a
concentrated solution of a single analyte prepared in the laboratory
with an assayed reference compound. Stock standard solutions are
used to prepare primary dilution standards.
3.11 PRIMARY DILUTION STANDARD SOLUTION — A solution of several analytes
prepared in the laboratory from stock standard solutions and diluted
as needed to prepare calibration solutions and other needed analyte
solutions.
3.12 CALIBRATION STANDARD (CAL) — A solution prepared from the primary
dilution standard solution and stock standard solutions of the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration.
3.13 QUALITY CONTROL SAMPLE (QCS) — A sample matrix containing method
analytes or a solution of method analytes in a water miscible
solvent which is used to fortify reagent water or environmental
samples. The QCS is obtained from a source external to the
laboratory, and is used to check laboratory performance with
externally prepared test materials.
4. INTERFERENCES
4.1 Method interferences may be caused by contaminants in solvents,
. reagents, glassware and other sample processing apparatus that lead
to discrete artifacts or elevated baselines in gas chromatograms.
All reagents and apparatus must be routinely demonstrated to be free
from interferences under the conditions of the analysis by running
laboratory reagent blanks as described in Sect. 9.2.
4.1.1 Glassware must be scrupulously cleaned (1). Clean all glass-
ware as soon as possible after use by thoroughly rinsing with
the last solvent used in it. Follow by washing with hot
water and detergent and thorough rinsing with tap and reagent
water. Drain dry, and heat in an oven or muffle furnace at
400°C for 1 hour. Do not heat volumetric ware. Thermally
stable materials might not be eliminated by this treatment.
Thorough rinsing with acetone may be substituted for the
heating. After drying and cooling, seal and store glassware
in a clean environment to prevent any accumulation of dust or
other contaminants. Store inverted or capped with aluminum
foil.
4.1.2 The use of high purity reagents and solvents helps to
minimize interference problems. Purification of solvents by
distillation in all-glass systems may be required. WARNING:
When a solvent is purified, stabilizers added by the
manufacturer may be removed thus potentially making the
solvent hazardous. Also, when a solvent is purified,
preservatives added by the manufacturer are removed thus
potentially reducing the shelf-life.
507-5
-------
4.2 Interfering contamination may occur when a sample containing low
concentrations of analytes is analyzed immediately following a
sample containing relatively high concentrations of analytes.
Between-sample rinsing of the sample syringe and associated
equipment with MTBE can minimize sample cross contamination. After
analysis of a sample containing high concentrations of analytes, one
or more injections of MTBE should be made to ensure that accurate
values are obtained for the next sample.
4.3 Matrix interferences may be caused by contaminants that are
coextracted from the sample. Also, note that all the analytes
listed in the scope and application section are not resolved from
each other on any one column, i.e., one analyte of interest may be
an interferant for another analyte of interest. The extent of
matrix interferences will vary considerably from source to source,
depending upon the water sampled. Further processing of sample
extracts may be necessary. Positive identifications should be
confirmed (Sect. 11.5).
4.4 It is important that samples and working standards be contained in
the same solvent. The solvent for working standards must be the
same as the final solvent used in sample preparation. If this is
not the case, chromatographic comparability of standards to sample
may be affected.
5. SAFETY
5.1 The toxicity or carcinogenicity of each reagent used in this method
has not been precisely defined; however, each chemical compound must
be treated as a potential health hazard. Accordingly, exposure to
these chemicals must be reduced to the lowest possible level. The
laboratory is responsible for maintaining a current awareness file
of OSHA regulations regarding the safe handling of the chemicals ~
specified in this method. A reference file of material safety data
sheets should also be made available, to all personnel involved in
the chemical analysis. Additional references to laboratory safety
are available and have been identified (2-4) for the information of
the analyst.
5.2 WARNING: When a solvent is purified, stabilizers added by the
manufacturer may be removed thus potentially making the solvent
hazardous.
6. EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.)
6.1 Sample bottle — Borosilicate, 1-L volume with graduations (Wheaton
Media/Lab bottle 219820 or equivalent), fitted with screw caps lined
with TFE-fluorocarbon. Protect samples from light. Amber bottles
may be used. The container must be washed and dried as described in
Sect. 4.1.1 before use to minimize contamination. Cap liners are
cut to fit from sheets (Pierce Catalog No. 012736 or equivalent) and
extracted with methanol overnight prior to use.
507-6
-------
6.2 GLASSWARE
6.2.1 Separatory funnel -- 2000-ml, with TFE-fluorocarbon stopcock,
ground glass or TFE-fluorocarbon stopper.
6.2.2 Tumbler bottle -- 1.7-L (Wheaton Roller Culture. Vessel or
equivalent), witn TFE-fluorocarbon lined screw cap. Cap
liners are cut to fit from sheets (Pierce Catalog No. 012736)
and extracted with methanol overnight prior to use.
6.2.3 Flask, Erlenmeyer -- 500-mL.
6.2.4 Concentrator tube, Kuderna-Danish (K-D) — 10- or 25-mL,
graduated (Kontes K-570050-2525 or K-570050-1025 or
equivalent). Calibration must be checked at, the volumes
employed in the test. Ground glass stoppers are used to
prevent evaporation of extracts.
6.2.5 Evaporative flask, K-D — 500-mL (Kontes K-570001-0500 or
equivalent). Attach to concentrator tube with springs.
6.2.6 Snyder column, K-D -- Three-ball macro (Kontes K-503000-0121
or equivalent).
6.2.7 Snyder column, K-D -- Two-ball micro (Kontes K-569001-0219 or
equivalent).
6.2.8 Vials — glass, 5- to 10-mL capacity with TFE-fluorocarbon
1ined screw cap. ,
6.3 Separatory funnel shaker (Optional) -- Capable of holding 2-L
separatory funnels and shaking them with rocking motion to achieve
thorough mixing of separatory funnel contents (available from
Eberbach Co. in Ann Arbor, MI or other suppliers).
6.4 Tumbler — Capable of holding tumbler bottles and tumbling 'them
end-over-end at 30 turns/min (Associated Design and Mfg. Co.,
Alexandria, VA. or other suppliers).
6.5 Boiling stones — Carborundum, #12 granules (Arthur H. Thomas Co.
#1590-033 or equivalent). Heat at 400°C for 30 min prior to use.
Cool and store in desiccator.
6.6 Water bath — Heated, capable of temperature control (+ 2°C). The
bath should be used in a hood.
6.7 Balance— Analytical, capable of accurately weighing to the nearest
0.0001 g.
6.8 GAS CHROMATOGRAPH — Analytical system complete with temperature
programmable GC suitable for use with capillary columns and all
required accessories including syringes, analytical columns, gases,
detector and stripchart recorder. A data system is recommended for
measuring peak areas. Table 1 lists retention times observed for
method analytes using the columns and analytical conditions
described below.
; ' 507-7
-------
6.8.1
6.8.2
Column 1 (Primary column) — 30 m long x 0.25 mm I.D. DB-5
bonded_fused silica column, 0.25 fim film thickness (J&W
Scientific) or equivalent. Helium carrier gas flow is
established at 30 cm/sec linear velocity and oven temperature
is programmed from 60°C to 300°C at 4°C/min. Data presented
in this method were obtained using this column. The
injection volume was 2 ni in splitless mode with a 45 s
delay. The injector temperature was 250°C and the detector
temperature was 300°C. Alternative columns may be used in
accordance with the provisions described in Sect. 9.4.
Column 2 (Confirmation column) — 30 m long x 0.25 mm
I.D.DB-1701 bonded fused silica column, 0.25 urn film
thickness (J&W Scientific) or equivalent. He!ium. carrier gas
flow is established at 30 cm/sec linear velocity and oven
temperature is programmed from 60C to 300°C at 4°C/min.
6.8.3 Detector — Nitrogen-phosphorus (NPD).
7. REAGENTS AND STANDARDS — WARNING: When a solvent is purified,
stabilizers added by the manufacturer are removed thus potentially making
the solvent hazardous. Also, when a solvent is purified, preservatives
added by the manufacturer are removed thus potentially reducing the
shelflife.
7.1 Acetone, methylene chloride, methyl tert.-butyl ether (MTBE) —
Distilled-in-glass quality or equivalent.
7.2 Phosphate buffer, pH 7 — Prepare by mixing 29.6 ml 0.1 N HC1 and 50
ml 0.1 M dipotassium phosphate.
7.3 Sodium chloride (NaCl), crystal, ACS grade — Heat treat in a
shallow tray at 400°C for a minimum of 4 hours to remove interfering
organic substances. Store in a glass bottle (not plastic) to avoid
phthalate contamination.
7.4 Sodium sulfate, granular, anhydrous, ACS grade — Heat treat in a
shallow tray at 400°C for a minimum of 4 hours to remove interfering
organic substances. Store in a glass bottle (not plastic) to avoid
phthalate contamination.
7.5 Sodium thiosulfate, granular, anhydrous, ACS grade.
7.6 Triphenylphosphate (TPP) -- 98% purity, for use as internal standard
(available from Aldrich Chemical Co.).
7.7 l,3-Dimethyl-2-nitrobenzene — 98%; purity, for use as surrogate
standard (available from Aldrich Chemical Co.).
7.8 Mercuric Chloride — ACS grade (Aldrich Chemical Co.), - for use as a
bactericide (optional- see Sect. 8).
7.9 Reagent water — Reagent water is defined as a water that is
reasonably free of contamination that would prevent the
determination of any analyte of interest. Reagent water used to
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I
generate the validation data in this method was distilled water
obtained from the Magnetic Springs Water Co., Columbus, Ohio.
7.10 STOCK STANDARD SOLUTIONS (1.00 fig/pi) — Stock standard solutions
may be purchased as certified solutions or prepared from pure
standard materials using the following procedure:
7.10.1 Prepare stock standard solutions by accurately weighing
approximately 0.0100 g of pure material. Dissolve the
material in MTBE and dilute to volume in a 10-mL volumetric
flask. The stock solution for simazine should be prepared in
methanol. Larger volumes may be used at the convenience of
the analyst. If compound purity is certified at 96% or
greater, the weight may be used without correction to
calculate the concentration of the stock standard.
Commercially prepared stock standards may be used at any
concentration if they are certified by the manufacturer or by
an independent source.
7.10.2 Transfer the stock standard solutions into
TFE-fluorocarbon-sealed screw cap amber vials. Store at room
temperature and protect from light. .
7.10.3 Stock standard solutions should be replaced after two months
or sooner if comparison with laboratory fortified blanks, or
QC samples indicate a problem.
7.11 INTERNAL STANDARD SOLUTION — Prepare the internal standard solution
, by accurately weighing approximately 0.0500 g of pure TPP. Dissolve
the TPP in MTBE and dilute to volume in a 100-mL volumetric flask.
Transfer the internal standard solution to a TFE-fluorocarbon-sealed
screw cap bottle and store at room temperature. Addition of 50 /iL
of the internal standard solution to 5 mL of sample extract results
in a final TPP concentration of 5.0 /xg/mL. This solution should be
replaced when ongoing QC (Sect. 9) indicates a problem. Note that
TPP has been shown to be an effective internal standard for the
method analytes, but other compounds may be used if the quality
control, requirements in Sect. 9 are met.
7.12 SURROGATE STANDARD SOLUTION — Prepare the surrogate standard
solution by accurately weighing approximately 0.0250 g of pure
l,3-dimethyl-2-nitrobenzene. .Dissolve the 1,3-dimethyl-
2-nitrobenzene in MTBE and dilute to volume in a 100-mL volumetric
flask. Transfer the surrogate standard solution to a
TFE-fluorocarbon-sealed screw cap bottle and store at room
temperature. Addition of 50 /uL of the surrogate standard solution
to a 1-L sample prior to extraction results in a 1,3-dimethyl-
2-nitrobenzene concentration in the sample of 12.5 /ig/L. Solution
should be replaced when ongoing QC (Sect. 9) indicates a problem.
Note that l,3-dimethyl-2-nitrobenzene has been shown to be an
effective surrogate standard for the method analytes, but other
compounds may be used if the qua!ity control requirements in Sect. 9
are met-.
7.13 LABORATORY PERFORMANCE CHECK SOLUTION —' Prepare the laboratory
performance check solution by adding 5 [j,L of the vernolate stock
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solution, 0.5 mL of the bromacil stock solution, 30 /ul_ of the
prometon stock solution, 15 /iL of the atrazine stock solution, 1.0
ml of the surrogate solution, and 500 nl of the internal standard
solution to a 100-mL volumetric flask. Dilute to volume with MTBE
and thoroughly mix the solution. Transfer to a TFE-fluorocarbon-
sealed screw cap bottle and store at room temperature. Solution
should be replaced when ongoing QC (Sect. 9) indicates a problem.
8. SAMPLE COLLECTION, PRESERVATION. AND STORAGE
8.1 Grab samples must be collected in glass containers. Conventional
sampling practices (5) should be followed; however, the bottle must
not be prerinsed with sample before collection.
8.2 SAMPLE PRESERVATION AND STORAGE
8.2.1 If residual chlorine is present, add 80 mg of sodium
thiosulfate per liter of sample to the sample bottle prior to
collecting the sample.
8.2.2 After the sample is collected in a bottle containing sodium
thiosulfate, seal the bottle and shake until dissolved.
8.2.3 The samples must be iced or refrigerated at 4°C away from
light from the time of collection until extraction. Pre-
servation study results indicated that most method analytes
present in samples were stable for 14 days when stored under
these conditions. The analytes disulfoton sulfoxide,
diazinon, pronamide, and terbufos exhibited significant
aqueous instability, and samples to be analyzed for these
compounds must be extracted immediately. The analytes
carboxin, EPTC, fluridone, metolachlor, napropamide,
tebuthiuron, and terbacil exhibited recoveries of less than
60% after 14 days. Analyte stability may be affected by the
matrix; therefore, the analyst should verify that the
preservation technique is applicable to the samples under
study.
8.2.4 All performance data presented in this method are from
samples preserved with mercuric chloride. No suitable
preservation agent (biocide) has been found other than
mercuric chloride. However the use of mercuric chloride is
not required due to its toxicity and potential harm to the
environment.
8.2.5 In some circumstances where biological degradation of target
pesticides might be expected, use of mercuric chloride may be
appropriate to minimize the possibility of false-negative
results. If mercuric chloride is to be used, add it (See
7.8) to the sample bottle in amounts to produce a
concentration of 10 mg/L. Add 1 ml of a solution containing
10 mg/ml of mercuric chloride in reagent water to the sample
bottle at the sampling site or in the laboratory before
shipping to the sampling site. A major disadvantage of
mercuric chloride is that it is a highly toxic chemical;
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mercuric chloride must be handled with caution, and samples
containing mercuric chloride must be disposed of properly.
8.3 Extract Storage -- Extracts should be stored at 4°C away from light.
Preservation study results indicate that most analytes are stable
for 28 days; however, a 14-day maximum extract storage time is
recommended. The analyst should verify appropriate extract holding
times applicable to the samples under study.
9. QUALITY CONTROL
9.1 Minimum quality control (QC) requirements are initial demonstration
of laboratory capability, determination of surrogate compound
recoveries in each sample and blank, monitoring internal standard
peak area or height in each sample and blank (when internal standard
calibration procedures are being employed), analysis of laboratory
reagent blanks, laboratory fortified samples, laboratory fortified
blanks, and QC samples. A method detection limit (MDL) must also be
determined for each analyte.
9.2 Laboratory Reagent Blanks. Before processing any samples, the
analyst must demonstrate that all glassware and reagent
interferences are under control. Each time a set of samples is
extracted or reagents are changed, a LRB must be analyzed. If
within the retention time window of any analyte of interest the LRB
produces a peak that would prevent the determination of that
analyte, determine the source of contamination and eliminate the
interference before processing samples.
9.3 Initial Demonstration of Capability.
9.3.1 Select a representative fortified concentration (about 10
times EDL or at a concentration in the middle of the
calibration range established in Sect. 10) for each analyte.
Prepare a standard concentrate containing each analyte at
1000 times the selected concentration. With a syringe, add 1
mL of the concentrate to each of four to seven 1-L aliquots
of reagent water, and analyze each aliquot according to
procedures beginning in Sect. 11.
9.3.2 For each analyte, the mean recovery value for these samples
must fall in the range of R ±30% using the values for R for
reagent water in Table 2. The RSD for these measurements
must be 20% or less. For those compounds that meet the
acceptance criteria, performance is considered acceptable.
For those compounds that fail these criteria, this procedure
must be repeated using fresh replicate samples until
satisfactory performance has been demonstrated.
9.3.3 For each analyte, determine the MDL. Prepare a minimum of 7
LFBs at a low concentration. The fortification concentration
in Table 3 may be used as a guide, or use calibration data
obtained in Section 10 to estimate a concentration for each
analyte that will produce a peak with a 3-5 times signal to
noise response. Extract and analyze each replicate according
to Sections 11 and 12. It is recommended that these LFBs be
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prepared and analyzed over a period of several days, so that
day to day variations are reflected in the precision
measurement. Calculate mean recovery and standard deviation
for each analyte. Use the equation given in Table 3 to
calculate the MDL.
9.3.3 The initial demonstration of capability is used primarily to
preclude a laboratory from analyzing unknown samples via a
new, unfamiliar method prior to obtaining some experience
with it. It is expected that as laboratory personnel gain
experience with this method the quality of data will improve
beyond those required here.
9.4 The analyst is permitted to modify GC columns, GC conditions,
concentration techniques (i.e. evaporation techniques), internal
standards or surrogate compounds. Each time such method
modifications are made, the analyst must repeat the procedures in
Sect. 9.3.
9.5 Assessing Surrogate Recovery
9.5.1 When surrogate recovery from a sample or method blank is <70%
or >130%, check calculations to locate possible errors,
fortifying solutions for degradation, contamination, and
instrument performance. If those steps do not reveal the
cause of the problem, reanalyze the extract.
9.5.2 If a LRB extract reanalysis fails the 70-130% recovery
criterion, the problem must be identified and corrected
before continuing.
9.5.3 If sample extract reanalysis meets the surrogate recovery
criterion, report only data for the reanalyzed extract. If
sample extract reanalysis continues to fail the recovery
criterion, report all data for that sample as suspect.
9.6 Assessing the Internal Standard
9.6.1 When using the internal standard calibration procedure, the
analyst is expected to monitor the IS response (peak area or
peak height) of all samples during each analysis day. The IS
response for any sample chromatogram should not deviate from
the daily calibration check standard's IS response by more
than 30%.
9.6.2 If >30% deviation occurs with an individual extract, optimize
instrument performance and inject a second aliquot of that
extract.
9.6.2.1 If the reinjected aliquot produces an acceptable
internal standard response report results for that
aliquot.
9.6.2.2 If a deviation of greater than 30% is obtained for
the reinjected extract, analysis of the sample
should be repeated beginning with Sect. 11, provided
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the sample is still available. Otherwise, report
results obtained from the reinjected extract, but
• . annotate as suspect.
9.6.3 If consecutive samples fail the IS response acceptance
criterion, immediately analyze a calibration check standard.
9.6.3.1 If the check standard provides a response factor
(RF) within 20% of the predicted value, then follow
procedures itemized in Sect. 9.6.2 for each sample
failing the IS response criterion.
9.6.3.2 If the check standard provides a response factor
which deviates more than 20% of the predicted value,
then the analyst must recalibrate, as specified-in
Sect. 9.
9.7 Assessing Laboratory Performance - Laboratory Fortified Blank
9.7.1 The laboratory must analyze at least one laboratory fortified
blank (LFB) sample with every twenty samples or one per
sample set (all samples extracted within a 24-h period)
whichever is greater. Ideally, the fortified concentration
of each analyte in the LFB should be the same concentration
selected in Section 9.3.1. '.Calculate accuracy as percent
recovery (X,-).. If the recovery of,any analyte falls outside
the control limits (see Sect. 9.7.2), that analyte is judged
out of control, and the source of the problem should be
identified and resolved before continuing analyses.
9.7.2 Until sufficient data become available from within their own
laboratory, usually a minimum of results from 20 to 30
analyses, the laboratory should assess laboratory performance
' against the control limits in Sect. 9.3.2 that are derived
from the data in Table 2. When sufficient internal
performance data becomes available, develop control limits
from the mean percent recovery (X) and standard deviation (S)
of the percent recovery. These data are used to establish
upper and lower control limits as follows:
UPPER CONTROL LIMIT = X + 3S
LOWER CONTROL LIMIT = X.- 3S
After each five to ten new recovery measurements, new control
limits should be calculated using only the most recent 20-30
data points. These calculated control limits must not exceed
the fixed limits listed in Sect. 9.3.2.
9.7.5 It is recommended that the laboratory periodically determine
and document its detection limit capabilities for analytes of
interest.
9.7.6 At least quarterly, analyze a QC sample from an outside
source.
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9.8 Assessing Analyte Recovery - Laboratory Fortified Sample Matrix
9.8.1 The laboratory must add a known concentration to a minimum of
5% of the routine samples or one sample per set, whichever is
greater. The fortified concentration should not be less than
the background concentration of the sample selected for
fortification. Ideally, the concentration should be the same
as that used for the laboratory fortified blank (Sect. 9.7).
Over time, samples from all routine sample sources should be
fortified.
9.8.2 Calculate the percent recovery, P, of the concentration for
each analyte, after correcting the analytical result, X, from
the fortified sample for the background concentration, b,
measured in the unfortified sample, i.e.,:
P = 100 (X - b) / .fortifying concentration,
and compare these values to reagent water recoveries listed
in Table 2. The calculated value of P must fall in the range
of R ± 35%. If P exceeds this control limit the results for
that analyte in the unfortified matrix must be listed as
suspect due to matrix interference.
9.9 ASSESSING INSTRUMENT SYSTEM - LABORATORY PERFORMANCE CHECK (LPC) -
After initial demonstration of capability, instrument performance
should be monitored on a daily basis by analysis of the LPC sample.
The LPC sample contains compounds designed to monitor instrument
sensitivity, column performance (primary column) and chromatographic
performance. LPC sample .components and performance criteria are
listed in Table 4. Inability to demonstrate acceptable instrument
performance indicates the need for reevaluation of the instrument
system. The sensitivity requirements are set based on the EDLs
published in this method. The purpose of the sensitivity
requirement is to monitor the stability of instrument sensitivity,
not as an absolute sensitivity requirement. If laboratory EDLs
differ from those listed in this method, concentrations of the LPC
standard compounds must be adjusted to be compatible with the
laboratory EDLs.
9.10 The laboratory may adopt additional quality control practices for '
use with this method. The specific practices that are most
productive depend upon the needs of the laboratory and the nature of
the, samples. For example, field or laboratory duplicates may be
analyzed to assess the precision of the environmental measurements
or field reagent blanks may be used to assess contamination of
samples under site conditions, transportation and storage.
10. CALIBRATION
10.1 Establish GC operating parameters equivalent to those indicated in
Sect. 6.8. The GC system may be calibrated using either the
internal standard technique (Sect. 10.2) or the external standard
technique (Sect. 10.3). Be aware that NPDs may exhibit instability
(i.e., fail to hold calibration curves over time). The analyst may,
when analyzing samples for target analytes which are very rarely
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found, prefer to analyze on a daily basis a low level (e.g. 5 to 10
times detection limit or 1/2 times the regulatory limit, whichever
is less), sample (containing all analytes of interest) and require
some minimum sensitivity (e.g. 1/2 full scale deflection) to show
that if the analyte were present it would be detected. The analyst
may then quantitate using single point calibration (Sect. 10.2.5 or
10.3.4). NOTE: Calibration standard solutions must be prepared
such that no unresolved analytes are mixed together.
10.2 INTERNAL STANDARD CALIBRATION PROCEDURE — To usejthis approach, the
analyst must select one or more internal standards compatible in
analytical behavior to the compounds of interest. The analyst must
further demonstrate that the measurement of the internal standard is
not affected by method or matrix interferences. TPP has been
identified as a suitable internal standard.
10.2.1 Prepare calibration standards at a minimum of three
(recommend five) concentration levels for each analyte of
interest by adding volumes of one or more stock standards to
a volumetric flask. Guidance on the number of standards is
as follows: A minimum of three calibration standards are
required to calibrate a range of a factor of 20 in
concentration. For a factor of 50 use at least four
standards, and for a factor of 100 at least five standards.
The lowest standard should represent analyte concentrations
near, but above, their respective EDLs. The remaining
standards should bracket the analyte concentrations expected
in the sample extracts, or should define the working range of
the detector. If Merphos is to be determined, calibrate with
DEF (S,S,S-tributylphosphoro-trithioate) . Merphos is
converted to S,S,S-tributylphosphoro-trithioate (DEF) in the
hot GC injection port; DEF is actually detected using the
analysis conditions in this method. To each calibration
standard, add a known constant amount of one or more of the
internal standards, and dilute to volume with MTBE.
10.2.2 Analyze each calibration standard according to the procedure
described in Sect. 11.4. Tabulate response (peak height or
area) against concentration for each compound and internal
standard. Calculate the response factor (RF) for each
analyte and surrogate using Equation 1. RF is a unitless
value.
RF = sis Equation 1
(Af.)(C.)
where ":
As = Response for the analyte.
Ajs = Response for the internal standard.
Cjs = Concentration of the internal standard
Cs = Concentration of the analyte to be measured M9/L.
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10.2.3 If the RF value over the working range is constant (20% RSD > s;
or less) the average RF can be used for calculations. • '
Alternatively, the results can be used to plot a calibration , •
curve of response ratios (As/Ajs) vs. Cs. '• ;';
10.2.4 The working calibration curve or calibration factor must be
verified on each working day by the measurement of a minimum
of two calibration check standards, one at the beginning and
one at the end of the analysis day. These check standards
should be at two different concentration levels to verify the
calibration curve. For extended periods of analysis (greater
than 8 hrs.), it is strongly recommended that check standards
be interspersed with samples at regular intervals during the
course of the analyses. If the response for any analyte
varies from the predicted response by more than ±20%, the
test must be repeated using a fresh calibration standard. If
the results still do not agree, generate a new calibration
curve. For those analytes that failed the calibration
verification, results from field samples analyzed since the
last passing calibration should be considered suspect.
Reanalyze sample extracts for these analytes after acceptable
calibration is restored'-.
10.2.5 Verify calibration standards periodically (at least
quarterly), by analyzing a QCS.
10.3 EXTERNAL STANDARD CALIBRATION PROCEDURE
10.3.1 Prepare calibration standards as in Section 10.2.1, omitting
the use of the internal standard.
10.3.2 Starting with the standard of lowest concentration, analyze
each calibration standard according to Sect. 11.4 and
tabulate response (peak height or area) versus the
concentration in the standard. The results can be used to
prepare a calibration curve for each compound.
Alternatively, if the ratio of response to concentration
(calibration factor) is a constant over the working range
(20% RSD or less), linearity through the origin can be
assumed and the average ratio or calibration factor can be :
used in place of a calibration curve.
10.3.3 The working calibration curve or calibration factor must be .
verified on each working day by the procedures described in
Section 10.2.4. -:, 't ,>,
; ' •'?•*&,
10.3.4 Verify calibration standards'periodically (at least . ,'.; ;V.7,V
quarterly), by analyzing a QCS. ,'-. '.'•^";
. •''.'^jf'1
11. PROCEDURE ••.:v-'?f*
. " * : V-v* ;
11.1 EXTRACTION (MANUAL, METHOD) ;: :;
11.1.1 Mark the water meniscus on the side of the sample bottle.for
later determination of sample volume (Sect. 11.1.6). Add
preservative (Section 8) to LRBs and LFBs. Fortify the
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. .sample with 50 /il_ of the surrogate standard solution. Pour
the entire sample into a 2-L separatory funnel.
11.1.2 Adjust the. sample to pH 7 by adding 50 ml of phosphate
buffer. Check pH. Add acid or base if necessary to obtain
. ..• . PH'7. ........
.,11.1.3 Add 100 g NaCl to the.-sample, seal, and shake to dissolve
.: salt*. ' ... .- .. .
11.1.4 Add 60 ml methylene chloride to the sample bottle, seal, and
shake 30 s to rinse the inner walls. Transfer the solvent to
the separatory funnel and extract the sample by vigorously
shaking the funnel for 2 min with periodic venting to release
excess pressure. Allow the organic layer to separate from
the water phase for a minimum of 10 min. If the emulsion
interface between layers is more than one third the volume of
the solvent layer, the analyst must employ mechanical
techniques to complete the phase separation. ••- The optimum
technique depends upon the sample, but may, include stirring,
.filtration of the emulsion through glass wool,
centrifugation, or other physical methods. Collect the
methylene chloride extract in a 500-mL Erlenmeyer flask.
11.1.5 Add a second 60-ml volume
of methylene chloride to the sample
uwwo.t ui.u icpcuu UMC cAui'action procedure a second tin
combining the extracts in the Erlenmeyer
bottle
econd 60-ml volume of methylene chloride
and repeat the extraction procedure a se
ng the extracts in the Erlenmeyer flask;.
third extraction in the same manner
second time,'
Perform;a
11.1.6 Determine the original sample volume by refilling the sample
bottle to the mark and transferring the water to a 1000-mL
graduated cylinder. Record the sample volume to the nearest
11.2 EXTRACTION (AUTOMATED METHOD) — Data presented in this method were
generated using the automated extraction procedure with the
mechanical tumbler. •
,,11.2.1 Mark the water meniscus on the side of the sample bottle for
: • later determination of sample volume (Sect. 11.2.6). Add
preservative to LRBs and LFBs. Fortify the sample with 50 ill
of the surrogate standard solution. If the mechanical
separatory funnel shaker is used, pour the entire sample into
, a 2-L separatory funnel. If the mechanical-tumbler is used,
pour the entire sample into a tumbler bottle.
11.2.2 Adjust the sample to pH 7 by adding 50 ml of phosphate
buffer. Check pH. Add acid or base if necessary to obtain
pH 7.
11.2.3 Add 100 g NaCl to the sample, seal, and shake to dissolve
salt. ,,
11.2.4 Add 3.0.0 mL methylene chloride to the sample bottle, seal, and
shake 30 s to rinse the inner walls. Transfer the solvent to
the sample contained in the separatory funnel or tumbler
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bottle, seal, and shake for 10 s, venting periodically.
Repeat shaking and venting until pressure release is not
observed. Reseal and place sample container in appropriate
mechanical mixing device (separatory funnel shaker or
tumbler). Shake or tumble the sample for 1 hour. Complete
mixing of the organic and aqueous phases should be observed
within about 2 min after starting the mixing device.
11.2.5 Remove the sample container from the mixing device. If the
tumbler is used, pour contents of tumbler bottle into a 2-L
separatory funnel. Allow the organic layer to separate from
the water phase for a minimum of 10 min. If the emulsion
interface between layers is more than one third the volume of
the solvent layer, the analyst must employ mechanical
techniques to complete the phase separation. The optimum
technique depends upon the sample, but may include stirring,
filtration through glass wool, centrifugation, or other
physical methods. Collect the methylene chloride extract in
a 500-mL Erlenmeyer flask...
11.2.6 Determine the original sample volume by refilling the sample
bottle to the mark and transferring the water to a 1000-mL
graduated cylinder. Record the sample volume to the nearest
5 ml.
11.3 EXTRACT CONCENTRATION
11.3.1 Assemble a K-D concentrator by attaching- a 25JmL concentrator
tube to a 500-mL evaporative flask. Other concentration
devices or techniques may be used in place of the K-D if the
requirements of Sect. 9.3 are met.
11.3.2 Dry the extract by pouring it through a solvent-rinsed drying
column containing about 10 cm of anhydrous sodium sulfate.
Collect the extract in the K-D concentrator, and rinse the
column with 20-30 mL methylene chloride. Alternatively, add
about 5 g anhydrous sodium sulfate to the extract in the
Erlenmeyer flask; swirl flask to dry extract and allow to sit
for 15 min. Decant the methylene chloride extract into the
K-D concentrator. Rinse the remaining sodium sulfate with
two 25-mL portions of methylene chloride and decant the
rinses into the K-D concentrator.
11.3.3 Add 1 to 2 clean boiling stones to the evaporative flask and
attach a macro Snyder column. Prewet the Snyder column by
adding about 1 mL methylene chloride to the top. Place the
K-D apparatus on a hot water bath, 65 to 70°C, so that the
concentrator tube is partially immersed in the hot water, and
the entire lower rounded surface of the flask is bathed with
hot vapor. Adjust the vertical position of the apparatus and
the water temperature as required to complete the
concentration in 15 to 20 min. At the proper rate of
distillation, the balls of the column will actively chatter,
but the chambers will not flood. When the apparent volume of
liquid reaches 2 mL, remove the K-D apparatus and allow it to
drain and cool for at least 10 min.
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11.3.4 Remove the Snyder column and rinse the. flask and its lower
joint into the concentrator tube with 1 to 2 ml of MTBE. Add
5-10 mL of MTBE and a fresh boiling stone. Attach a
micro-Snyder column to the concentrator tube and prewet the
column by adding about 0.5 ml of MTBE to the top. Place the
micro K-D apparatus on the water bath so that the
concentrator tube is partially immersed in the hot water.
Adjust the vertical position of the apparatus and the water
temperature as required to complete concentration in 5 to 10
min. When the apparent volume of liquid reaches 2 ml, remove
the micro K-D from the bath and allow it to drain and cool.
. Add 5-10 ml MTBE to the micro K-D and reconcentrate to 2 ml
Remove the micro K-D from the bath and allow it to drain and
cool. Remove the micro Snyder column, and rinse the walls of
the concentrator tube while adjusting the volume to 5.0 ml
with MTBE. NOTE: If methylene chloride is not completely
removed from the final extract, it may cause detector
problems. If the internal standard calibration procedure is
used, add 50 /iL of the internal standard solution to the
sample extract, seal, and shake to distribute the internal
standard.
11.3.5 Transfer extract to an appropriate- sized TFE-fluorocarbon-
sealed screw-cap vial and store, refrigerated at 4°C, until
analysis by GC-NPD.
11.4 GAS CHROMATOGRAPHY
11.4.1 Sect. 6.8 summarizes the recommended operating conditions for
the gas chromatograph. Included in Table 1 are retention
times observed using this method. Other GC columns or
chromatographic conditions may be used if the requirements of
Sect. 9 are met.
11.4.2 Verify the calibration the system daily as described in Sect.
10.2.4 or 10.3.3. The standards and extracts must be in
MTBE.
11.4.3 Inject 2 /il_ of the sample extract. Record the resulting peak
size in area units.
11.4.4 If the response for the peak exceeds the working range of the
system, dilute the extract and reanalyze. If using IS
calibration, add an appropriate amount of IS so that the
extract concentration will match the calibration standards.
11.5 IDENTIFICATION OF ANALYTES
11.5.1 Identify a sample component by comparison of its retention
time to the retention time of a reference chromatogram. If
the retention time of an unknown compound corresponds, within
limits, to the retention time of a standard compound, then
identification is considered positive.
11.5.2 The width of the retention time window used to make
identifications should be based upon measurements of actual
507-19
-------
retention time variations of standards over the course of a
day. Three times the standard deviation of a retention time
can be used to calculate a suggested window size for a
compound. However, the experience of the analyst should
weigh heavily in the interpretation of chromatograms.
11.5.3 Identification requires expert judgement when sample
components are not resolved chromatographically. When peaks
obviously represent more than one sample component (i.e.,
broadened peak with shoulder(s) or valley between two or more
maxima), or any time doubt exists over the identification of
a peak on a chromatogram, appropriate alternative techniques
to help confirm peak identification, need be employed. For
example, more positive identification may be made by the use
of an alternative detector which operates on a
chemical/physical principle different from that originally
used, e.g., mass spectrometry (6), or the use of a second
chromatography column. A suggested alternative column is
described in Sect. 6.8.
12. CALCULATIONS
12.1 Calculate analyte concentrations in the sample from the response
for the analyte using the procedure for multi-point calibration
described in Sect. 10. Do not use the daily calibration
verification standard to calculate analye amounts in samples.
12.2 If the internal standard calibration procedure is used, calculate
the concentration (C) in the sample using the response factor (RF)
determined in Sect. 10.2.2 and Equation 2, or determine sample
concentration from the calibration curve.
C (pg/L) = (AS)(U Equation 2
(A,s)(RF)(Vo)
where:
As - Response for the parameter to be measured.
Ais - Response for the internal standard.
I = Amount of internal standard added to each extract (Mg).
Vo = Volume of water extracted (L).
12.3 If the external standard calibration procedure is used, calculate
the amount of material injected from the peak response using the
calibration curve or calibration factor determined in Sect. 10.3.2.
The concentration (C) in the sample can be calculated from
Equation 3.
C (M9/L) = v M t; Equation 3
(V,)(V8)
507-20
-------
, where:
A = Amount of material injected (ng).
V,. = Volume of extract injected
Vt = Volume of total extract
Vs = Volume of water extracted (ml).
13. PRECISION AND ACCURACY
13.1 In a single laboratory, analyte recoveries from reagent water were
used to determine analyte MDLs, EDLs (Table 3) and demonstrate
method range. Analytes were divided into five groups for recovery
studies. Analyte recoveries and standard deviation about the
. percent recoveries at one concentration are given in Table 2.
13.2 In a single laboratory, analyte recoveries from two standard
synthetic ground waters were determined at one concentration level.
Results were used to demonstrate applicability of the method to
different ground water matrices. Analyte recoveries from the two
synthetic matrices are given in Table 2.
14. POLLUTION PREVENTION
14.1 This method uses significant volumes of organic solvents. It is
highly recommended that laboratories use solvent recovery systems
to recover used solvent as sample extracts are being concentrated.
Recovered solvents should be recycled or properly disposed of.
14.2 For information about pollution prevention that may be applicable
to laboratory operations, consult "Less is Better: Laboratory
Chemical Management for Waste Reduction" available from the
American Chemical Society's Department of Government Relations and
Science Policy, 1155 16th Street N.W., Washington, D.C. 20036.
15. WASTE MANAGEMENT
15.1 It is the laboratory's responsibility to comply with all federal,
state, and local regulations governing waste management, particu-
larly the hazardous waste identification rules and land disposal
restrictions. The laboratory using this method has the responsi-
bility to protect the air, water, and land by minimizing and
controlling all releases from fume hoods and bench operations.
Compliance is also required with any sewage discharge permits and
regulations. For further information on waste management, consult
"The Waste Management Manual for Laboratory Personnel," also
available from the American Chemical Society at the address in
Sect. 14.2.
16. REFERENCES
• , ;
1. ASTM Annual Book of Standards, Part 11, Volume 11.02, D3694-82,
"Standard Practice for Preparation of Sample Containers and for
507-21
-------
"Preservation," American Society for Testing and Materials, Philadel-
phia, PA, 1986.
2. "Carcinogens - Working with Carcinogens," Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77-206, Aug. 1977.
3. "OSHA Safety and Health Standards, General Industry," (29 CFR 1910),
Occupational Safety and Health Administration, OSHA 2206, (Revised,
January 1976).
4. "Safety in Academic Chemistry Laboratories," American Chemical
Society Publication, Committee on Chemical Safety, 3rd Edition, ,1979.
5. ASTM Annual Book of Standards, Part 11, Volume 11.01, D3370-82,
"Standard Practice for Sampling Water," American Society for Testing
and Materials, Philadelphia, PA, 1986.
6. Munch, J. W., "Method 525.2-Determination of Organic Compounds in
Drinking Water by Liquid-Solid Extraction and Capillary Column
Chromatography/ Mass Spectrometry" in Methods for the Determination
of Organic Compounds in Drinking Water: Supplement 3 (1995). USEPA,
National Exposure Research Laboratory, Cincinnati, Ohio 45268.
507-22
-------
TABLE 1. RETENTION TIMES FOR METHOD ANALYTES
Retention Time3
Analyte Col. 1 Col. 2
l,3-Dimethyl-2-nitrobenzene( surrogate)
Dichlorvos
Disulfoton sulfoxide
EPIC
Butyl ate
Mevinphos
Vernolate
Pebulate
Tebuthiuron
Molinate
Ethoprop
Cycloate
Chlorpropham
Atraton
Simazine
Prometon
Atrazine
Propazine
Terbufos
Pronamide
Diazinon
Disulfoton
Terbacil
Metribuzin
Methyl paraoxon
Simetryn
Alachlor
Ametryn
Prometryn
Terbutryn
Bromacil
Metolachlor
Triademefon
MGK 264 (c)
Diphenamid
Stirofos
Disulfoton sulfone
Butachlor
Fenamiphos
Napropamide
Tricyclazole
Merphos (d)
Carboxin
Norflurazon
Triphenyl phosphate (int. std.)
14.48
16.54
19.08
20.07
22.47
22.51
22.94
23.41
25.15
25.66
28.58
28.58
29.09
31.26
31.49
31.58
31.77
32.01
32.57
32.76
33.23
33.42
33.79
35.20
35.58
35.72
35.96
36.00
36.14
36.80
37.22
37.74
38.12
38,73
38.87
41.27
41.31
41.45
41.78
41.83
42.25
42.35
42.77
45.92
47
(b)
15.35
(b)
16.57
18.47
21.92
19.25
19.73
42.77
22.47
26.42
29.67
(b)
29.97
31.32
30.00
31.23
31.13
(b)
32.63
(b)
30.90
(b)
34.73
34.10
34.55
34.10
34.52
34.23
34.80
40.00
35.70
37.00
36.73
37.97
39.65
42.42
39.00
41.00
(b)
44.33
39.28
42.05
47.58
45.40
507-23
-------
TABLE 1 (CONTINUED)
Retention Time3.
Analyte Col.l Col.2
Hexazinone
Fenarimol
Fl undone
46.58
51.32
56.68
47.80
50.02
59.07
8 Columns and analytical conditions are described in Sect. 6.8.1 and 6.8.2,
b Data not available
c MGK 264 gives two peaks; peak identified in this table used for
quantification.
Merphos is converted to S,S,S-tributylphosphoro-trithioate (DEF) in the
hot GC injection port; DEF is actually detected using these analyses
conditions.
d
507-24
-------
TABLE 2.
SINGLE LABORATORY ACCURACY AND PRECISION FOR ANALYTES FROM
REAGENT WATER AND SYNTHETIC GROUNDWATERS3
Analyte
A achlor
Ametryn
Atraton
Atrazine
Bromacil
Butachlo
Butyl ate
Carboxin
Chlorpropham
Cycloate
Diazinon
Dichlorvos
Diphenamid
Disulfoton
Disulfoton sulfone
Disulfoton sulfoxide
EPIC
Ethoprop
Fenamiphos
Fenarimol
Fluridone
Hexazinone
Merphos
Methyl paraoxon
Metol achlor
Metribuzin
Mevinphos
MGK 264
Mol inate
Napropamide
Norflurazon
Pebulate
Prometon
Prometryn
Pronamide
Propazine
Simazine
Simetryn
Stirofos
Tebuthiuron
Terbacil
Terbufos
Terbutryn
• Cone.
378
• 20
6
1.3
25
3.8 •
1.5.
6
5
2.5
2.5
25
6
.3
, 7.5
3.8
2.5
1.9
' 10
3.8
38
7.6
2.5
25
7.5
1.5
50
5
1.5
2.5
5.
1.3
3
1.9
7.6
1.3
0.75
2.5
7.6
13
45
5
2.5
Reagent
Water
Rb SRC
95
91
91
92
91
96
97
102
93
89
115
97
93
89
98
87
85
103
90
99
87
90
96
98
93
101
95
100
98
101
94
94
78
93
91
92
100
99
98
84
97
97
94
11
10
11
8
9
4
21
4
11
9
7 .:
6
8
10
10
11
9
5
8
5
9
7
8
10
4
5
11
4
18
6
5
9
9
8
10
8
7
5
6
9
6
4
9
Synthetic
Water ld
R SR
82
102 .
84
89
81
93
36
98
82
97
83
86
88
107
92
88
83
91
87
89
91
86
90
97
92
99
93
91
83
89
.101
80
89
91
84
89
86
88
84
85
86
80
91
6
11
7
6
5
15
8
13
7
14
8
6
4
12
5
22
5
7
5
6
11
6 '
4
8
10
10
6
11
8
5
15
6
5
8
7
6
5
4
6
10
5
6
8
Synthetic
Water 2e
R SR
90
96
91
92
88
84
83
87
93
93 .
84
106
93
95
! 96
54
86
79
89
89
86
95
92
94
84
86
92
83
89
104
87
98
63
93
92
92
103
103
95
98,
102
77
92
8
4
8
5
8
5
8
5
8
3
3
16
5
5
3
19
4
3
2
6
10
g
4
4
4
4
4
6
9
18
4
15
2
4
8
5
14
14
10
13
12
7
4
507-25
-------
TABLE 2. (CONTINUED)
Analyte
Cone.
M9/L
Reagent
Water
Rb SRC
Synthetic
Water ld
R SR
Synthetic
Water 2e
R SR
Triademefon
Tricyclazole
Vernolate
6.5
10
1.3
93
86
93
8
7
6
94
90
79
5
6
9
95
90
81
5
11
2
Data corrected for blank and represent the analysis of 7-8 samples using
mechanical tumbling and internal standard calibration.
R = average percent recovery.
S = standard deviation of the percent recovery.
Corrected for amount found in blank; Absopure Nature Artesian Spring Water
Obtained from the Absopure Water Company in Plymouth, Michigan.
Corrected for amount found in blank; reagent water fortified with fulvic acid
at the 1 mg/L concentration level. A well-characterized fulvic acid,
available from the International Humic Substances Society (associated with
the United States Geological Survey in Denver, Colorado), was used.
507-26
-------
TABLE 3.
SINGLE LABORATORY ACCURACY, PRECISION, METHOD DETECTION LIMITS
(MDLs) AND ESTIMATED DETECTION LIMITS (EDLs) FOR ANALYTES FROM
REAGENT WATER
Analyte
Fortified Cone. Na Recovery RSD
MDL
EDLC
Alachlor
Ametryn
Atraton
Atrazine
Bromacil
Butachlor
Butyl ate
Carboxin
Chlorpropham
Cycloate
Diazinon
Dichlorvos
Diphenamid
Disulfoton
Disulfoton sulfone
Disulfoton sulfoxide
EPIC
Ethoprop
Fenamiphos
Fenarimol
Fluridone
Hexazinone
Merphos
Methyl paraoxon
Metolachlor
Metribuzin
Mevinphos
MGK 264
Molinate
Napropamide
Norflurazon
Pebulate
Prometon
Prometryn
Pronamide
Propazine
Simazine
Simetryn
Stirofos
Tebuthiuron
Terbacil
Terbufos
Terbutryn
0.38
2.0
0.60
0.13
2.5
0.38
0.15
0.60
0.50
0.25
0.25
2.5
0.60
0.30
3.8
0.38
0.25
0.19
1.0
0.38
3.8
0.76
0.25
2.5
0.75
0.15
5.0
0.50
0.15
0.25
0.50
0.13
0.30
0.19
0.76
0.13
0.075
0.25
0..76
1.3
4.5
0.5
0.25
8
8
8
8
8
8
8
8
8
8
8
8
8
8
7
7
8
8
8
8
7
8
8
8
8
8
8
8
8
8
8
8
7
8
8
8
8
8
8
8
8
8
8
119
100
120
101
113
99
93
101
124
101
94
78
84
100
94
110
87
108
91
92
78
127
101
100
94
114
92
101
117
97
86
84
48
88
123
93
99
97
121
101
100
91
91
10
3
8
4
8
11
13
10
11
3
18
5
5
3
6
6
12
3
4
19
30
5
5
4
9 •
6
6
12
12
9
8
7
9
5
10
4
6
5
7
15
4
4
4
0.14
0.20
0.17
0.015
0.69
0.12
0.053
0.18
0.20
0.022
0.13
0.28
0.082
0.029
0.63
0.082
0.080
0.021
0.12
0.20
2.8
0.15 •
0.040
0.30
0.19
0.029
0.87
0.19
0.061
0.069
0.098
0.022
0.041
0.024
0.28
0.014
0.014
0.035
0.18
0.58
0.56
0.054
0.031
0.38
2.0
0.6
0.13
2.5
0.38
0.15
0.60
0.50
0.25
0.25
2.5
0.60
0.30
3.8,
0.38
0.25
0.19
1.0
0.38
3.8
0.76
0.25
2.5
0.75
0.15
5.0
0.50
0.15
0.25
0.50
0.13
0.30
0.19
0.76
0.13
0.075
0.25
0.76
1.3
4.5
0.50
0.25
507-27
-------
TABLE 3. (CONTINUED)
MDL Cone.
Analyte
Tri ademef on
Tricyclazole
Vernol ate
MQ/L Na
0.65 8
1.0 8
0.13 8
. Recovery
#g/L
95
216
100
RSD
%
5
3
14
MDLb
W/L
0.093
0.21
0.055
EDLC
yg/L
0.65
1.0
0.13
* N - Number of Replicates
b With thi
=><;e data, the method c
detection 1
imits (MDL) in
the table
s were
calculated using the formula:
MDL - S t(n_., j.atpha = 0.99)
where:
t , „ , u n oo^ = Student's t value for the 99% confidence level
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507-29
-------
THIS PAGE LEFT BLANK INTENTIONALLY
507-30
-------
METHOD 508. DETERMINATION OF CHLORINATED PESTICIDES IN WATER BY GAS
CHROMATOGRAPHY WITH AN ELECTRON CAPTURE DETECTOR
Revision 3.1
Edited by J.W. Munch (1995)
J. J. Lichtenberg, J. E. Longbottom, T. A. Bellar, J. W. Eichelberger
and R. C. Dressman - EPA 600/4-81-053, Revision 1.0 (1981)
D. J. Munch (USEPA, Office of Water) and T. Engel (Battelle Columbus
Laboratories) - National Pesticide Survey Method 2, Revision 2.0 (1987)
R. L. Graves - Method 508, Revision 3.0 (1989)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
508-1
-------
METHOD 508
DETERMINATION OF CHLORINATED PESTICIDES IN WATER BY
GAS CHROHATOGRAPHY WITH AN ELECTRON CAPTURE DETECTOR
1. SCOPE AND APPLICATION
1.1 This is a gas chromatographic (GC) method applicable to the
determination of certain chlorinated pesticides in groundwater and
finished drinking water. The following compounds can be determined
using this method:
Analvte
Aldrin
Chlordane-alpha
Chlordane-gamma
Chlorneb
Chlorobenzilate(a)
Chlorothalonil
DC PA
4,4'-DDD
4,4'-DDE
4,4'-DDT
Dieldrin
Endosulfan I
Endosulfan II
Endosulfan sulfate
Endrin
Endrin aldehyde
Etridiazole
HCH-alpha
HCH-beta
HCH-delta(a)
HCH-gamma (Lindane)
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Methoxychlor
cis-Permethrin
trans-Permethrin
Propachlor
Trifluralin
Aroclor 1016*
Aroclor 1221*
Aroclor 1232*
Aroclor 1242*
Aroclor 1248*
Aroclor 1254*
Aroclor 1260*
Chemical Abstract Service
Registry Number '
309-
5103-
5103-
2675-
501-
2921-
1861-
72-
72-
50-
60-
959-
33213-
1031-
72-
7421-
2593-
319-
319-
319-
58
76-
1024
118
72
52645
52645
1918
1582
12674
11104
11141
53469
12672
11097
11096
00-2
71-9
74-2
77-6
15-6
88-2
32-1
54-8
55-9
29-3
57-1
98-8
65-9
07-8
20-8
93-4
•15-9
•84-6
•85-7'
•86-8
•89-9
•44-8
-57-3
-74-1
-43-5
-53-1
-53-1
-16-7
-09-8
-11-2
-28-2
-16-5
-21-9
-29-6
-69-1
-82-5
508-2
-------
Toxaphene* 8001-35-2
Chlordane* 57-74-9
M Jh! !£JracJ1on conditi°ns of this method are comparable to USEPA
Method 608, which does measure the multicomponent constituents-
commercial polychlorinated biphenyl (PCS) mixtures (Aroclors)
toxaphene, and chlordane. The extract derived from this procedure
may be analyzed for these constituents by using the GC conditions
prescribed in either Method 608 (packed column) or Methods 505
SOS.ror 525.2 (capillary column)(l). The columns used -in this
method may well be adequate, however, no data were collected for
these constituents during methods development.
(a) Chlorbenzilate and HCH-delta are only qualitatively identified
and are not quantitated because control over precision has not been
accomplished.
1.2 This method has been validated in a single laboratory and estimated
detection limits (EDLs) and method detection limits (MDLs) have been
determined for the analytes above (Sect. 13). Observed detection '
limits may vary between waters, depending upon the nature of
^ the sample matrix and the specific instrumentation
1.3 This method is restricted to use by or under the supervision of
analysts experienced in the use of GC and in the interpretation of
gas chromatograms. Each analyst must demonstrate the ability to
1.4
o
generate acceptable results with this method using the procedure
described in Sect. 9.3. ,
Analytes that are not separated chromatographically, i.e., analytes
which have very similar retention times, cannot be individually
identified and measured in the same calibration mixture or water
sample unless an alternative technique for identification and
quantitation exist, (Sect. 11.5).
1.5 When this method is used to analyze unfamiliar samples for any or
all of the analytes above, analyte identifications must be confirmed
by at least one additional qualitative technique.
2. SUMMARY OF METHOD
2.1 A measured volume of sample of approximately 1 L is solvent
extracted with methylene chloride by shaking in a separatory funnel
or mechanical tumbling in a bottle. The methylene chloride extract
is isolated, dried and concentrated to a volume of 5 mL after
solvent substitution with methyl tert-butyl ether (MTBE) . Chroma-
tographic conditions are described which permit the separation and
measurement of the analytes in the extract by capillary column GC
with an electron capture detector (ECO).
508-3
-------
3. DEFINITIONS
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
INTERNAL STANDARD — A pure analyte(s) added to a solution in known
amount(s) and used to measure the relative responses of other method
analytes and surrogates that are components of the same solution.
The internal standard must be an analyte that is not a sample
component.
SURROGATE ANALYTE — A pure analyte(s), which is extremely unlikely
to be found in any sample, and which is added to a sample aliquot in
known amount(s) before extraction and is measured with the same
procedures used to measure other sample components. The purpose of
a surrogate analyte is to monitor method performance with each
sample.
LABORATORY DUPLICATES (LD1 and LD2) — Two sample aliquots taken in
the analytical laboratory and analyzed separately with identical
procedures. Analyses of LD1 and LD2 give a measure of the precision
associated with laboratory procedures, but .not with sample
collection, preservation, or storage procedures.
FIELD DUPLICATES (FD1 and FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as well as with
laboratory procedures.
LABORATORY REAGENT BLANK (LRB) — An aliquot of reagent water that
is treated exactly as a sample including exposure to all glassware,
equipment, solvents, reagents, internal standards, and surrogates
that are used with other samples. The LRB is used to determine if
method analytes or other interferences are present in the laboratory
environment, the reagents, or the apparatus.
FIELD REAGENT BLANK (FRB) — Reagent water placed in a sample
container in the laboratory and treated as a sample in all respects,
including exposure to sampling site conditions, storage,
preservation and all analytical procedures. The purpose of the FRB
is to determine if method analytes or other interferences are
present in the field environment.
LABORATORY PERFORMANCE CHECK SOLUTION (LPC) — A solution of method
analytes, surrogate compounds, and internal standards used to
evaluate the performance of the instrument system with respect to a
defined set of method criteria.
LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water to
which known quantities of the method analytes are added in the
laboratory. The LFB is analyzed exactly like a sample, and its
purpose is to determine whether the methodology is in control, and
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whether the laboratory is capable of making accurate and precise
measurements at the required method detection limit.
3.9 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
. analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
3.10 STOCK STANDARD SOLUTION — A concentrated solution containing a
single certified standard that is a method analyte, or a
concentrated solution of a single analyte prepared in the laboratory
with an assayed reference compound. Stock standard solutions are
used to prepare primary dilution standards.
3.11 PRIMARY DILUTION STANDARD SOLUTION — A solution of several analytes
prepared in the laboratory from stock standard solutions and diluted
as needed to prepare calibration solutions and other needed analyte
solutions.
3.12 CALIBRATION STANDARD (CAL) — A solution prepared from the primary
dilution standard solution and stock standard solutions of the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration.
3.13 QUALITY CONTROL SAMPLE (QCS) — a sample matrix containing method
analytes or a solution of method analytes in a water miscible
solvent which is used to fortify reagent water or environmental
samples. The QCS is obtained from a source external to the
laboratory, and is used to check laboratory performance with
externally prepared test materials.
4. INTERFERENCES
4.1 Method interferences may be caused by contaminants in solvents,,
reagents, glassware and other sample processing apparatus that lead
to discrete artifacts or elevated baselines in gas chromatograms.
All reagents and apparatus must be routinely demonstrated to be free
from interferences under the conditions of the analysis by running
laboratory reagent blanks as described in Sect. 9.2.
4.1.1 Glassware must-be scrupulously cleaned (2). Cle.an all glass-
ware as soon as possible after use by thoroughly rinsing with
the last solvent used in it. Follow by washing with hot
water and detergent and thorough rinsing with tap and reagent
water. Drain dry, and heat in an oven or muffle furnace at
400°C for 1 hour. Do not heat volumetric glassware.
Thermally stable materials such as PCBs might not be
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eliminated by this treatment. Thorough rinsing with acetone
may be substituted for the heating. After drying and
cooling, seal and store glassware in a clean environment to
prevent any accumulation of dust or other contaminants.
Store inverted or capped with aluminum foil.
4.1.2 The use of high purity reagents and solvents helps to
minimize interference problems. Purification of solvents by
distillation in all-glass systems may be required. WARNING:
When a solvent is purified, stabilizers added by,the
manufacturer are removed thus potentially making the solvent
hazardous. Also, when a solvent is purified, preservatives
added by the manufacturer are removed thus potentially
reducing the shelf-life.
4.2 Interferences by phthalate esters can pose a major problem in pesti-
cide analysis when using the electron capture detector. These
compounds generally appear in the chromatogram as large peaks.
Common flexible plastics contain varying amounts of phthalates that
are easily extracted or leached during laboratory operations. Cross
contamination of clean glassware routinely occurs when plastics are
handled during extraction steps, especially when solvent-wetted
surfaces are handled. Interferences from phthalates can best be
minimized by avoiding the use of plastics in the laboratory.
Exhaustive cleanup of reagents and glassware may be required to
eliminate background phthalate contamination. ' :.
4.3 Interfering contamination may occur when a sample containing Tow
concentrations of analytes is analyzed immediately following a
sample containing relatively high concentrations of analytes.
Between-sample rinsing of the sample syringe and associated
equipment with MTBE can minimize sample cross contamination. After
analysis of a sample containing high concentrations of analytes, one
or more injections of MTBE should be made to ensure that accurate
values are obtained for the next sample.
4.4 Matrix interferences may be caused by contaminants that are
coextracted from the sample. Also, note that all the analytes
listed in the Scope and Application Section are not resolved from
each other on any one column, i.e., one analyte of interest may be
an interferant for another analyte of interest. The extent of
matrix interferences will vary considerably from source to source,
depending upon the water sampled. Analyte identifications should be
confirmed (Sect. 11.5).
4.5 It is important that samples and standards be contained in the same
solvent, i.e., the solvent for final working standards must be the
same as the final solvent used in sample preparation. If this is
not the case, chromatographic comparability of standards to sample
may be affected.
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5. SAFETY
5.1 The toxicity or carcinogenicity of each reagent used in this method
has not been precisely defined; however, each chemical compound must
be treated as a potential health hazard. Accordingly, exposure to
these chemicals must be reduced to the lowest possible level. The
laboratory is responsible for maintaining a current awareness file
of OSHA regulations regarding the safe handling of the chemicals
specified in this method. A reference file of material safety data
sheets should also be made available to all personnel involved in
the chemical analysis. Additional references to laboratory safety
are available and have been identified (3-5) for the information of
the analyst.
5.2 WARNING: When a solvent is purified stabilizers added by the
manufacturer are removed thus potentially making the solvent
hazardous.
6- EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.)
6.1 SAMPLE BOTTLE — Borosil icate, 1-L volume with graduations (Wheaton
Media/Lab bottle 219820 or equivalent), fitted with screw caps lined
with TFE-fluorocarbon. Protect samples from light. Amber bottles
may be used. The container mu.st be washed and dried as described in
Sect. 4.1.1 before use to minimize contamination. Cap liners are
cut to fit from sheets (Pierce Catalog No. 012736) and extracted
with methanol overnight prior to use.
6.2 GLASSWARE
6.2.1 Separatory funnel — 2000-mL, with TFE-fluorocarbon stopcock
ground glass or TFE-fluorocarbon stopper.
6.2.2 Tumbler bottle 1.7-L (Wheaton Roller Culture Vessel or
equivalent), with TFE-fluorocarbon lined screw cap. Cap
liners are cut to fit from sheets (Pierce Catalog No. 012736)
and extracted with methanol overnight prior to use.
6.2.3 Flask, Erlenmeyer — 500-mL.
6.2.4 Concentrator tube, Kuderna-Danish (K-D) 10- or 25-mL
graduated (Kontes K-570050-1025 or K-570050-2525 or
equivalent). Calibration must be checked at the volumes
employed in the test. Ground glass stoppers are used to
prevent evaporation of extracts.
6.2.5 Evaporative flask, K-D 500-mL (Kontes K-570001-0500 or
equivalent). Attach to concentrator tube with springs.
6.2.6 Snyder column, K-D three-ball macro (Kontes K-503000-0121 or
equivalent).
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6.2.7 Snyder column, K-D two-ball micro (Kontes K-569001-0219 or
equivalent).
6.2.8 Vials — Glass, 5- to 10-mL capacity with TFE-fluorocarbon
lined screw cap.
6.3 SEPARATORY FUNNEL SHAKER — Capable of holding 2-L separatory
funnels and shaking them with rocking motion to achieve thorough
mixing of separatory funnel contents (available from Eberbach Co. in
Ann Arbor, MI or other suppliers).
6.4 TUMBLER — Capable of holding tumbler bottles and tumbling them
end-over-end at 30 turns/min (Associated Design and Mfg. Co.,
Alexandria, VA or other suppliers.).
6.5 BOILING STONES CARBORUNDUM, #12 granules (Arthur H. Thomas Co.
#1590-033 or equivalent). Heat at 400°C for 30 min prior to use.
Cool and store in a desiccator.
6.6
6.7
6.8
WATER BATH — Heated, capable of temperature control (± 2°C).
bath should be used in a hood.
The
BALANCE — Analytical, capable of accurately weighing to the. nearest
0.0001 g.
GAS CHROMATOGRAPH — Analytical system complete with temperature
programmable GC suitable for use with capillary columns and all
required accessories including syringes, analytical columns, gases,
detector and stripchart recorder. A data system is recommended for
measuring peak areas. Table 1 lists retention times observed for
method analytes using the columns and analytical conditions
described below.
6.8.1 Column 1 (Primary column) — 30 m long x 0.25 mm I.D. DB-5
bonded fused silica column, 0.25 fim film thickness (J&W
Scientific). Helium carrier gas flow is established at 30
cm/sec linear velocity and oven temperature is programmed
from 60°C to 300°C at 4°C/min. Data presented in this method
were obtained using this column. The injection volume was 2
/iL splitless mode with a 45 sec. delay. The injector
temperature was 250°C and the detector temperature was 320°C.
Column performance criteria are presented in Table 4 (See
Section 9.9). Alternative columns may be used in accordance
with the provisions described in Sect. 9.4.
6.8.2 Column 2 (Alternative column) — 30 m long x 0.25 mm
I.D.DB-1701 bonded fused silica column, 0.25 jitm film
thickness (J&W Scientific). Helium carrier gas flow is
established at 30 cm/sec linear velocity and oven temperature
is programmed from 60°C to 300°C at 4°C/min.
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6.8.3 Detector — Electron capture. This detector has proven
effective in the analysis of fortified reagent and artificial
ground waters.
REAGENTS AND STANDARDS - - WARNING: When a solvent is purified,
stabilizers added by the manufacturer are removed thus potentially making
the solvent hazardous. Also, when a solvent is purified, preservatives
added by the manufacturer are removed thus potentially reducing the
shelf-life.
7.1 ACETONE, methylene chloride, MTBE — Distilled-in-glass quality or
equivalent.
7.2 PHOSPHATE BUFFER, pH 7 Prepare by mixing 29.6 ml 0.1 N HC1 and 50 ml
0.1 M dipotassium phosphate.
7.3 SODIUM CHLORIDE, crystal, ACS grade. Heat treat in a shallow tray
at 400°C for a minimum of 4 hours to remove interfering organic
substances. Store in a glass bottle (not plastic) to avoid
phthalate contamination.
7.4 SODIUM SULFATE, granular, anhydrous, ACS grade. Heat treat in a
shallow tray at 450°C for a minimum of 4 hours to remove interfering
organic substances. Store in a glass bottle (not plastic) to avoid
phthalate contamination.
7.5 SODIUM THIOSULFATE, granular, anhydrous, ACS grade. .
7.6 PENTACHLORONITROBENZENE (PCNB) 98% purity, for use as internal
standard.
7.7 DECACHLOROBIPHENYL (DCB) 96% purity, for use as surrogate standard
(available from Chemicals Procurement Inc.).
7.8 MERCURIC CHLORIDE — ACS grade — for use as a bactericide
(optional).
J .9 REAGENT WATER — Reagent water is defined as water that is
reasonably free of contamination that would prevent the
determination of any analyte of interest. Reagent water used to
generate the validation data in this method was distilled water
obtained from the Magnetic Springs Water Co., Columbus, Ohio.
7.10 STOCK. STANDARD SOLUTIONS (1.00 /jg/ML) — Stock standard solutions
may be purchased as certified solutions or prepared from pure
standard materials using the following procedure:
7.10.1 Prepare stock standard solutions by accurately weighing
approximately 0.0100 g of pure material . Dissolve the
material in MTBE and dilute to volume in a 10-mL volumetric
flask. Larger volumes may be used at the convenience of the
analyst. If compound purity is certified at 96% or greater,
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the weight may be used without correction to calculate the •
concentration of the stock standard. Commercially prepared
stock standards may be used at any concentration if they are
certified by the manufacturer or by an independent source.
7.10.2 Transfer the stock standard solutions into TFE-fluoro-
carbon-sealed screw cap amber vials. Store at room temper-
ature and protect from light.
7.10.3 Stock standard solutions should be replaced after two months
or sooner if comparison with laboratory fortified blanks, or
QC samples indicate a problem.
7.11 INTERNAL STANDARD SOLUTION -- Prepare an internal standard
fortifying solution by accurately weighing approximately 0.0010 g of
pure PCNB. Dissolve the PCNB in MTBE and dilute to volume in a
10-mL volumetric flask. Transfer the internal standard solution to
a TFE-fluorocarbon-sealed screw cap bottle and store at room
temperature. Addition of 5 fil of the internal standard fortifying
solution to 5 mL of sample extract results in a final internal
standard concentration of 0.1 /zg/mL. Solution should be replaced
when ongoing QC (Sect. 9) indicates a problem. Note that PCNB has
been shown to be an effective internal standard for the method
analytes, but other compounds may be used if the quality control
requirements in Section 9 are met.
7.12 SURROGATE STANDARD SOLUTION — Prepare a surrogate standard
fortifying solution by accurately weighing approximately 0.0050 g of
pure DCB. Dissolve the DCB in MTBE and dilute to volume in a 10-mL
volumetric flask. Transfer the surrogate standard fortifying
solution to a TFE-fluorocarbon-sealed screw cap bottle and store at
room temperature. Addition of 50 /zL of the surrogate standard
fortifying solution to a 1-L sample prior to extraction results in
a surrogate standard concentration in the sample of 25 //g/L and,
assuming quantitative recovery of DCB, a surrogate standard
concentration in the final extract of 5.0 tig/ml. Solution should be
replaced when ongoing QC (Sect. 9) indicates a problem. Note DCB
has been shown to be an effective surrogate standard for the method
analytes, but other compounds may be used if the quality control
requirements in Section 9 are met.
7.13 LABORATORY PERFORMANCE CHECK SOLUTION -- Prepare by accurately
weighing 0.0010 g each of chlorothalonil, chlorpyrifos, DCPA, and
HCH-delta. Dissolve each analyte in MTBE and dilute to volume in
individual 10-mL volumetric flasks. Combine 2 /zL of the
chloropyrifos stock solution, 50 (il of the DCPA stock solution, 50
fil of the chlorothalonil stock solution, and 40 ill of the HCH-delta
stock solution to a 100-mL volumetric flask and dilute to volume
with MTBE. Transfer to a TFE-fluorcarbon-sealed screw cap bottle
and store at room temperature. Solution should be replaced when
ongoing QC indicates a problem.
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7.14 GO DEGRADATION CHECK SOLUTION — Prepare a solution in MTBE
containing .endrin and 4,4'-DDT each at a concentration of 1 fig/ml.
This solution will be injected to check for undesirable degradation
of these compounds in the injection port by looking for endrin
aldehyde and endrin ketone or for 4,4'- DDE and 4,4'- ODD.
i
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.. 1 Grab samples must be collected in glass containers. Conventional
sampling practices (6) should be followed; however, the bottle must
not be prerinsed with sample before collection.
8.2 SAMPLE PRESERVATION
8.2.1 If residual chlorine is present, add 80 mg of sodium
thiosulfate per liter of sample to the sample bottle prior to
collecting the sample.
8.2.2 After adding the sample to the bottle containing sodium
thiosulfate, seal the sample bottle and shake until
dissolved. .
8.2.3 Samples must be iced or refrigerated at 4°C from the time of
collection until extraction. Preservation study results
indicate that most of the target analytes present in the
samples are stable for 7 days when stored under these
. • conditions. Preservation data for the analytes
chlorthalonil, alpha-HCH, delta-HCH, gamma-HCH, cis-
permethrin, trans-permethrin, and trifluralin are
nondefinitive, and therefore if these are analytes of
interest, it is recommended that the samples be analyzed
immediately. Analyte stability may be affected by the
matrix; therefore, the analyst should verify that the
, preservation technique is applicable to the- samples under
• study. ' '• *
8.2.4 All performance data presented in this method are from
samples preserved with mercuric chloride. No suitable
preservation agent (biocide) has been found other than
mercuric chloride. However, the use of mercuric chloride is
not required due to its toxicity and potential harm to the
environment.
8.2.5 In 'some circumstances where biological degradation of target
pesticides might be expected, use of mercuric chloride may be
appropriate to minimize the possibility of false-negative
results. If mercuric chloride is to be used, add it to the
•. sample bottle in amounts to produce a concentration of
10 mg/L. Add 1 mL of a solution containing 10 mg/mL of
mercuric chloride in reagent water to the sample bottle at
the sampling site or in the laboratory before shipping to the
sampling site. A major disadvantage of mercuric chloride is
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that it is a highly toxic chemical; mercuric chloride must be
handled with caution, and samples containing mercuric
chloride must be disposed of, properly.
8.3 EXTRACT STORAGE
8.3.1 Sample extracts should be stored at 4°C away from light. A
14-day maximum extract storage time is recommended. However,
analyte stability may be affected by the matrix; therefore,
the analyst should verify appropriate extract holding times
applicable to the samples under study.
9. QUALITY CONTROL
9.1 Minimum quality control (QC) requirements are initial demonstration
of laboratory capability, determination of surrogate compound
recoveries in each sample and blank, monitoring internal standard
peak area or height in each sample and blank (when internal standard
calibration procedures are being (employed), analysis of laboratory
reagent blanks, laboratory fortified samples, laboratory fortified •
blanks, and QC samples. An MDL for each analyte must also be
determined.
9.2 Laboratory Reagent Blanks — Before processing any samples, the
analyst must demonstrate that all glassware and reagent
interferences are under control. Each time a set of samples is
extracted or reagents are changed, a laboratory reagent blank (LRB)
must be a'nalyzed. If within the retention time window of any
analyte of interest the LRB produces a peak that would prevent the
determination of that analyte, determine the source of contamination
and eliminate the interference before processing samples.
9.3 INITIAL DEMONSTRATION OF CAPABILITY
9-.3.1 Select a representative fortified concentration (about 10
times EDL or at a concentration that represents a mid-point
of the calibration range for each analyte. Prepare a primary
dilution standard (in methanol) containing each analyte at
1000 times selected concentration. With a syringe, add 1 mL
of the concentrate to each:of four to seven 1-L aliquots of
reagent water, and analyze each of these LFBs according to
procedures beginning in Section 11.
9.3.2 For each analyte, the recovery value for all replicates must
fall in the range of R ± 30% using the value for R
demonstrated for reagent water in Table 2. The precision of
the measurements, calculated as relative standard deviation
(RSD), must be 20% or less. For those compounds that fail
these criteria, this procedure must be repeated using four
fresh samples until satisfactory performance has been
demonstrated.
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9.3.3 For each analyte, determine the MDL. Prepare a minimum of 7
LFBs at a low concentration. Fortification concentration in
Table 3 may be used as a guide, or use calibration data
obtained in Section 10 to estimate a concentration for each
analyte that will produce a peak with a 3-5 times signal to
noise response. Extract and analyze each replicate according
to Sections 11 and 12. It is recommended that these LFBs be
prepared and analyzed over a period of several days, so that
day to day variations are reflected in the precision data.
Calculate mean recovery and standard deviation for each
analyte. Use the equation given in Table 3 to calculate the
MDL.
9.3.4 The initial demonstration of capability is used primarily to
preclude a laboratory from analyzing unknown samples via a
new, unfamiliar method prior to obtaining some experience
with it. It is expected that as laboratory personnel gain
experience with this method the quality of data will improve
beyond those required here.
9.4 The analyst is permitted to modify GC columns, GC conditions,
concentration techniques (i.e. evaporation techniques), internal
standards or surrogate compounds. Each time such method
modi.fications are made, the analyst must repeat the procedures in
Section 9.3.
9.5 ASSESSING SURROGATE RECOVERY
9.5.1 When surrogate recovery from a sample or method blank is <70%
or >130%, check calculations to locate possible errors,
fortifying solutions for degradation, contamination or other
obvious abnormalities, and instrument performance. If those
steps do not reveal the cause of the problem, reanalyze the
extract.
9.5.2 If a LRB extract reanalysis fails the 70-130% recovery
criterion, the problem must be identified and corrected
before continuing.
9.5.3 If sample extract reanalysis meets the surrogate recovery
criterion, report only data for the reanalyzed extract. If.
sample extract reanalysis continues to fail the surrogate
recovery criterion, report all data for that sample as
suspect.
9.6 ASSESSING THE INTERNAL STANDARD
9.6.1 When using the internal standard calibration procedure, the
analyst must monitor the IS response (peak area or peak
height) of all samples during each analysis day. The IS
response for any sample chromatogram should not deviate from
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9.6.2
the daily calibration check standards IS response by more
than 30%.
If >30% deviation occurs with an individual extract, optimize
instrument performance and inject a second aliquot of that
extract. • •
9.6.2.1 If the reinjected aliquot produces an acceptable '
internal standard response report results for that
aliquot.
9.6.2.2 If a deviation of greater than 30% is obtained for
the re-injected extract, analysis of the sample
should be repeated beginning with Section 11,
provided the sample is still available. Otherwise,
report results obtained from the re-injected
extract, but annotate as sUspect.
9.6.3 If consecutive samples fail the IS response acceptance
criterion, immediately analyze a calibration check standard.
9.6.3.1 If the check standard provides a response factor
(RF) within 20% of the predicted value, then follow
procedures itemized in Section 9.6.2 for each sample
failing the IS response criterion.
9.6.3.2 If the check standard provides a response factor
which deviates more than 20% of the predicted value,
then the analyst must recalibrate, as specified in
Section 10. After calibration is restored,
reanalyze sample extracts that failed Sect 9.6.2
criteria.
9.7 ASSESSING LABORATORY PERFORMANCE - LABORATORY FORTIFIED BLANK
9.7.1 The laboratory must analyze at least one laboratory fortified
blank (LFB) sample with every twenty samples or one per
sample set (all s'amples extracted within a 24-h period)
whichever is greater. The fortified concentration of each
analyte in the LFB should be 10 times EDL or a concentration
that represents a mid-point of the calibration range.
Calculate accuracy as percent recovery (X,). If the recovery
of any analyte falls outside the control limits (see Sect.
9.7.2), that analyte is judged out of control, and the source
of the problem should be identified and resolved before
continuing analyses.
Note: It is suggested that one multi-component analyte
(toxaphene, chlordane or an Aroclor) LFB also be analyzed
with each sample set. By selecting a different multi-
component analyte for this LFB each work shift, LFB data can
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be obtained for all of these analytes over the course of
several days.
9.7.2 Until sufficient data becomes available from within their own
laboratory, usually a minimum of results from 20 to 30
analyses, the laboratory should assess laboratory performance
against the control limits in Sect. 9.3.2 that are derived
from the data in Table 2. When sufficient internal
performance data becomes available, .develop control limits
from the mean percent recovery (X) and standard deviation (S)
of the percent recovery. These data are used to establish
upper and lower control limits as follows:
UPPER CONTROL LIMIT - X + 3S
LOWER CONTROL LIMIT = X - 3S
After each five to ten new recovery measurements, new control
limits should be calculated using only the most recent 20-30
data points. These calculated control limits should not
exceed those established in Sect. 9.3.2.
9.7.3 It is recommended that the laboratory periodically document
and determine its detection limit capabilities for the
analytes of interest.
9.7.4 At least quarterly, analyze a QC sample from an outside
source.
9.8 ASSESSING METHOD PERFORMANCE - LABORATORY FORTIFIED SAMPLE MATRIX
9.8.1 The laboratory must add a known concentration to a minimum of
10% of the routine samples or one sample per set, whichever
is greater. The added concentration should not be less then
the background concentration of the sample selected for
fortification. Ideally, the fortified analyte concentrations
should be the same as that used for the LFB (Section .9.7).
Over time, samples from all routine sample sources should be
fortified.
9.8.2 Calculate the percent recovery, P, of the concentration for
each analyte, after correcting the analytical result, X, from
the fortified sample for the background concentration, b,
measured in the unfortified sample, i.e.,:
P = 100 (X - b) / fortifying concentration,
and compare these values to reagent water recoveries listed
in Table 2. The calculated value of P must fall in the range
of R ± 35%. If P exceeds this control limit, and the
laboratory performance for that analyte is shown to be in
control (Sect. 9.7), the recovery problem encountered with
the dosed sample is judged to be matrix related, not system
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related. The result for that analyte in the unfortified
sample is labeled suspect/matrix to inform the data user that
the results are suspect due to matrix effects.
9.9 ASSESSING INSTRUMENT SYSTEM - LABORATORY PERFORMANCE CHECK (LPC)
9.9.1 Laboratory performance check (LPC). After initial
demonstration of capability, instrument performance should be
monitored on a daily basis by analysis of the LPC sample.
The LPC sample contains compounds designed to monitor
instrument sensitivity, column performance (primary column)
and chromatographic performance. LPC sample components and
performance criteria are listed in Table 4. Inability to
demonstrate acceptable instrument performance indicates the
need for reevaluation of the instrument system. The
sensitivity requirements are set based on the EDLs published
in this method. If laboratory EDLs differ from those listed
in this method, concentrations of the LPC standard compounds
must be adjusted to be compatible with the laboratory EDLs.
9.9.2 Degradation of DDT and endrin caused by active sites in the
injection port and GC columns may occur. This should be
checked on a daily basis by injecting the GC degradation
check solution. Look for the degradation products of 4,4'-
DDT (4,4'-DDE and 4,4'-DDD) and the degradation products of
endrin (endrin aldehyde, EA and endrin ketone, EK). For
4,4'-DDT, these products will elute just before, the parent,
and for endrin, the products will elute just after the
parent. If degradation of either DDT or endrin exceeds 20%,
resilanize the injection port liner and/or break off a meter
from the front of the column. The degradation check solution
is required each day in which analyses are performed.
% degrade = Total DDT degradation peak area (DDE+DDD) X100
of 4,4'DDT Total DDT peak area (DDT+DDE+DDD)
% degrade = Total EA + EK peak area X100
of endrin Total endrin-fEA+EK area
NOTE: If the analyst can verify that 4,4 DDT, endrin, their
breakdown products, and the analytes in the IPC solution are
all resolved, the IPC solution and the GC degradation check
solution may be prepared and analyzed as a single solution.
9.10 The laboratory may adopt additional quality control practices for
use with this method. The specific practices that are most
productive depend upon the needs of the laboratory and the nature of
the samples. For example, field or laboratory duplicates may be
analyzed to assess the precision of the environmental measurements
or field reagent blanks may be used to asses contamination of
samples under site conditions, transportation and storage.
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10. CALIBRATION
10.1 Establish GC operating parameters equivalent to those .indicated in
Sect. 6.8. The GC system must be calibrated using the internal
standard technique (Sect. 10.2) or the external standard technique
(Sect. 10.3). Perform, the endrin and DDT degradation check
described in Sect. 9.9.2. If degradation of either DDT or endrin
exceeds 20%, take corrective action before proceeding with
calibration.
10.2 INTERNAL STANDARD CALIBRATION PROCEDURE — To use this approach, the
analyst must select one or more internal standards compatible in
analytical behavior to the compounds of interest. The analyst must
further demonstrate that the measurement of the internal standard is
not affected by method or matrix interferences. PCNB has been
identified as a suitable internal standard. Data presented in this
• method were generated using the internal standard calibration
procedure.
10.2.1 Prepare calibration standards at a minimum of three
(recommend five) concentration levels for each analyte of
interest by.adding volumes of one or more stock standards to
a volumetric flask. To each calibration standard, add a
known constant amount of one or more of the internal
standards, and dilute to volume with MTBE. Guidance on the
number of standards is as follows: A minimum of three
calibration standards are required to calibrate a range of a
factor of 20 in concentration. For a factor of 50, use at
least four standards, and for a factor of 100, at least five
standards. The lowest standard should represent analyte
concentrations near, but above, their respective EDLs. The
remaining standards should bracket the analyte concentrations
expected in the sample extracts, or should define the working
range of the detector. The calibration standards must
bracket the analyte concentration found in the sample
extracts. NOTE: Calibration standard solutions must be
prepared such that no unresolved analytes are mixed together,
and calibration standards for toxaphene, chlordane and each
of the Aroclors must be prepared individually.
10.2.2 Analyze each calibration standard according to the procedure
(Sect. 11.4). Tabulate response (peak height or area)
against concentration for each compound and internal
standard. Calculate the response factor (RF) for each
analyte and surrogate using Equation 1. RF is a unitless
value.
(A8)(Cis)
RF = Equation 1
(A,.)(C.)
where :
508-17
-------
= Response for the analyte to be measured.
= Response for the internal standard.
= Concentration of the internal standard (p.g/1).
= Concentration of the analyte to be measured
Note: For options on calculating response factors for multi-
component analytes refer to Sect. 12.4.
10.2.3 If the RF value over the working range is constant (20% RSD
or less) the average RF can be used for calculations.
Alternatively, the results can be used to plot a calibration
curve of response ratios (As/Ajs) vs. Cs.
10.2.4 The working calibration curve or calibration factor must be
verified on each working day by the measurement of a minimum
of two calibration check standards, one at the beginning and
one at the end of the analysis day. These check standards
should be at two different concentration levels to verify the
calibration curve. For extended periods of analysis (greater
than 8 hrs.), it is strongly recommended that check standards
be interspersed with samples at regular intervals during the
course of the analyses. If the response for any analyte
varies from the predicted response by more than ±20%, the
test must be repeated using a fresh calibration standard. ...If
the results still do not agree, generate a new calibration
curve. For those analytes that failed the calibration
verification, results from field samples analyzed since the
last passing calibration should be considered suspect.
Reanalyze sample extracts for these analytes after acceptable
calibration is restored. WARNING: A dirty injector insert
will cause poor sensitivity for the late eluting analytes.
NOTE: It is suggested that a calibration verification
standard of one multi-component analyte also be analyzed each
day or work shift. By alternating the selection of the
multi-component analyte chosen, continuing calibration data
can be obtained for all of these analytes over a period of
several days.
10.2.5 Verify calibration standards periodically, recommend at least
quarterly, by analyzing a standard prepared from reference
material obtained from an independent source (QCS). Results
from these analyses must be within the limits used to
routinely check calibration (Sect. 10.2.4).
10.3 EXTERNAL STANDARD CALIBRATION PROCEDURE
10.3.1 Prepare calibration standards as in Section 10.2.1, omitting
the use of the internal standard. •
10.3.2 Starting with the standard of lowest concentration, analyze
each calibration standard according to Sect. 11.4 and
508-18
-------
tabulate response (peak height or area) versus the
concentration in the standard. The results can be used to
prepare a calibration curve for each compound.
Alternatively, if the ratio of response to concentration
(calibration factor) is a constant over the working range
(20% RSD or less), linearity through the origin can be
assumed and the average ratio or calibration factor can be
used in place of a calibration curve.
Note: For options on calulating a calibration factor for
multi-component analytes, refer to Sect. 12.4.
10.3.3 The working calibration curve or calibration factor must be "
verified on each working day by the procedures described in
Section 10.2.4. Note: It is suggested that one multi-
component analyte calibration be verified each day or work
shift. , By alternating the selection of the analyte (an
., Aroclor or tpxaphene), calibration verification data can be
.obtained for all these analytes over a period of several
days.
. 10.3.4 Verify calibration standards periodically (at least
quarterly), by analyzing a QCS.
11. PROCEDURE
11.1 EXTRACTION (MANUAL METHOD)
11.1.1 Mark the water meniscus on the side of the sample bottle for
later determination of sample volume (Sect. 11.1.6). Add
preservative to LRBs and LFBs. Fortify the sample with 50>L
of the surrogate standard fortifying solution. Pour the
entire sample into a 2-L separatory funnel.
11.1.2 Adjust the sample to pH 7 by adding 50 mL of phosphate
buffer. Check pH: add H2S04 or NaOH if necessary.
11.1.3 Add 100 g NaCl to the sample, seal, and shake to dissolve
salt.
11.1.4 Add 60 ml methylene chloride to the sample bottle, seal, and
, shake 30 s to rinse the inner walls. Transfer the solvent to
the separatory funnel and extract the sample fay vigorously
shaking the funnel for 2 min with periodic venting to release
excess pressure. Allow the organic layer to separate from
the water phase for a minimum of 10 min. If the emulsion
interface between layers is more than one third the volume of
the solvent layer, the analyst must employ mechanical
techniques to complete the phase separation. The optimum
technique depends upon the sample, but may include stirring,
filtration of the emulsion through glass wool,
508-19
-------
centrifugation, or other physical methods. Collect the
methylene chloride extract in a 500-mL Erlenmeyer flask.
11.1.5 Add a second 60-mL volume of methylene chloride to the sample
bottle and repeat the extraction procedure a second time,
combining the extracts in the Erlenmeyer flask. Perform a
third extraction in the same manner.
11.1.6 Determine the original sample volume by refilling the sample
bottle to the mark and transferring the water to a 1000-mL
graduated cylinder. Record the sample Volume to the nearest
5 mL.
11.2 AUTOMATED EXTRACTION METHOD — Data presented in this method were
generated using the automated extraction procedure with the
mechanical tumbler.
11.2.1 Mark the water meniscus on the side of the sample bottle for
later determination of sample volume (Sect. 11.2.6). Add
preservative to LRBs and LFBs. Fortify the sample with 50 /zL
of the surrogate standard fortifying solution. If the
mechanical separatory funnel shaker is used, pour the entire
sample into a 2-L separatory funnel. If the mechanical
tumbler is used, pour the entire sample into a tumbler
bottle.
*
11.2.2 Adjust the sample to pH 7 by adding 50 ml of phosphate
buffer. Check pH: add H2S04 or NaOH if necessary.
11.2.3 Add 100 g NaCl to the sample, seal, and shake to dissolve
salt.
11.2.4 Add 300 ml methylene chloride to the sample bottle, seal, and
shake 30 s to rinse the inner walls. Transfer'the solvent to
the sample contained in the separatory funnel or tumbler
bottle, seal, and shake for 10 s, venting periodically.
Repeat shaking and venting until pressure release is not
observed during venting. Reseal and place sample container
in appropriate mechanical mixing device (separatory funnel
shaker or tumbler). Shake or tumble the sample for 1 hour.
Complete mixing of the organic and aqueous phases should be
observed within about 2 min after starting the mixing device.
11.2.5 Remove the sample container from the mixing device. If the
tumbler is used, pour contents of tumbler bottle into a 2-L
separatory funnel. Allow the organic layer to separate from
the water phase for a minimum of 10 min. If the emulsion
interface between layers is more than one third the volume of
the solvent layer, the analyst must employ mechanical
techniques to complete the phase separation. The optimum
technique depends upon the sample, but may include stirring,
filtration through glass wool, centrifugation, or other
508-20
-------
physical methods. Collect the methylene chloride extract in'
a 500-mL Erlenmeyer flask.
11.2.6 Determine the original sample volume by refilling the sample
bottle to the mark and transferring the water to a 1000-mL
graduated cylinder. Record the sample volume to the nearest
5 ml.
11.3 EXTRACT CONCENTRATION
11.3.1 Assemble a K-D concentrator by attaching a 25-mL concentrator
tube to a 500-mL evaporative flask. Other concentration
devices or techniques may be used in place of the K-D if the
requirements of Sect. 9.3 are met.
11.3..2 Dry the extract by pouring it through a solvent-rinsed drying
column containing about 10 cm of anhydrous sodium sulfate
Collect the extract in the K-D concentrator, and rinse the
column with 20-30 ml methylene chloride; Add this rinse to
the extract. Alternatively, add about 5 g anhydrous sodium
sulfate to dry the extract in the Erlenmeyer flask; swirl the
flask to dry extract and allow to sit for 15 min. Decant the
methylene chloride extract into the K-D concentrator. Rinse
the remaining sodium sulfate with two 25-mL portions of
methylene chloride and decant the rinses into the K-D
concentrator.
11.3.3 Add 1 to 2 clean boiling stones to the evaporative flask and
attach a macro Snyder column. Prewet the Snyder column by
', adding about 1 mL methylene chloride to the top Place the
K-D apparatus on a hot water bath, 65 to 70°C, so that the
concentrator tube is partially immersed in the hot water and
the entire lower rounded surface of the flask is bathed with
hot vapor. Adjust the vertical position of the apparatus and
the water temperature as required to complete the
concentration in 15 to 20 min. At the proper rate of
distillation the balls of the column will actively chatter
but the chambers will not flood. When the apparent volume'of
liquid reaches 2 mL, remove the K-D apparatus and allow it to
drain and cool for at least 10 min.
11.3.4 Remove the Snyder column and rinse the flask and its lower
joint into the concentrator tube with 1 to 2 mL of MTBE. Add
5-10 mL of MTBE and a fresh boiling stone. Attach a
micro-Snyder column to the concentrator tube and prewet the
column by adding about 0.5 mL of MTBE to the top. Place the
micro K-D apparatus on the water bath so that the
concentrator tube is partially immersed in the hot water.
Adjust the vertical position of the apparatus and the water
temperature as required to complete concentration in 5 to 10
mm. When the apparent volume of liquid reaches 2 mL, remove
the micro K-D from the bath and allow it to drain and cool.
508-21
-------
Add 5-10 mL MTBE to the micro K-D and reconcentrate to 2 mL.
Remove the micro K-D from the bath and allow it to drain and
cool. Remove the micro Snyder column, and rinse the walls of
the concentrator tube while adjusting the volume to 5.0 ml
with MTBE.
11.3.5 Transfer extract to an appropriate-sized TFE-fluorocarbon-
sealed screw-cap vial and store, refrigerated at 4°C, until
f analysis by GC-ECD.
11.4 GAS CHROMATOGRAPHY
11.4.1 Sect. 6.8 summarizes the recommended operating conditions for
the gas chromatogfaph. Included in Table 1 are retention
times observed using this method. Other GG columns,
chromatographic conditions, or detectors may be used if the
requirements of Sect. 9.3 are met.
11.4.2 Calibrate or verify the system calibration daily as described
in Sect. 10. The standards and extracts must be in MTBE.
11.4.3 If the internal standard calibration procedure is used, add
5 tJ,L of the internal standard fortifying solution to the
sample extract, seal, and shake to distribute the internal
standard.
11.4.4 Inject 2 /iL of the sample extract. Record the resulting peak
size in area units.. .
11.4.5 If the response for the peak exceeds the working range of the
system, dilute the extract and reanalyze. If internal
standard calibration has been used, add an appropriate amount
of additional internal standard to maintain the a
concentration of 0.1 fjg/ml.
11.5 IDENTIFICATION OF ANALYTES
11.5.1 Identify a sample component by comparison of its retention
time to the retention time of a reference chromatogram. If
the retention time of an unknown compound corresponds, within
limits, to the retention time of a standard compound, then
identification is considered positive.
11.5.2 The width of the retention time window used to make
identifications should be based upon measurements of actual
retention time variations of standards over the course of a
day. Three times the standard deviation of a retention time
can be used to calculate a suggested window size for a
compound. However, the experience of the analyst should
weigh heavily in. the interpretation of chromatograms.
508-22
-------
11,5.3 Identification requires expert judgment when sample
components are not resolved chromatographically. When GC
peaks obviously .represent more than one sample component
(i.e., broadened peak with shoulder(s) or valley between two
or more maxima), or any time doubt exists over the
identification of a peak on a chromatogram, appropriate
alternate techniques, .to help confirm peak identification,
need to be employed. For example, more positive
identification may be made by the use of an alternative
detector which operates on a chemical/physical principle
different from that originally used; e.g., mass spectrometry
(Method 525.2) (1), or the use of a second chromatography
column. A suggested alternative column is described in Sect.
6.8.
Note: Identify multi-component analytes by comparison of the
sample chromatogram to the corresponding calibration standard
chromatograms of chlordane, toxaphene and the Aroclors.
Identification of multi-component analytes is made by pattern
recognition, in which the experience of the analyst is an
important factor.
12. CALCULATIONS
12.1 Calculate analyte concentrations in the sample from the response for
the analyte using one of the multi-point calibration procedures
described in Sect. 10. Do not use the daily calibration
verification standard to calculate the amount of method analytes in
samples.
12.2 If the internal standard calibration procedure is used, calculate
the concentration (C) in the sample using the calibration curve or
response factor (RF) determined in Sect. 10.2 and,Equation 2. RF is
a unitless value.
•(A8)(i.)
C (tig/I) = Equation 2
(A,S)(RF)(V0)
where:
As = Response for the parameter to be measured.
Ajs = Response for the internal standard.
Is = Amount of internal standard added to each extract
V0 = Volume of water extracted (L).
12.3 If the external standard calibration procedure is used, calculate
the amount of material injected from the peak response using the
calibration curve or calibration factor determined in Section 10.3
The concentration (C) in the sample can be calculated from
Equation 3.
508-23
-------
c (/ig/L) =
where:
(A)(Vt)
(V,)(V8)
Equation 3
:i
= Amount of material injected (ng)
- Volume of extract injected (fiL).
= Volume of total extract (ill).
= Volume of water extracted (ml). '
12.4 To quantitate multi-component analytes, one of the following methods
should be used.
Option 1- Calculate an average response factor, calibration factor
or linear regression equation for each multi-component analyte using
the combined area of all the component peaks in each of the
calibration standard chromatograms.
Option 2- Calculate an average response factor, calibration factor
or linear regression equation for each multi-component analyte using
the combined areas of 3-6 of the most intense and reproducible peaks
in each of the calibration standard chromatograms.
When quantifying multi-component analytes in samples, the analyst
should use caution to include only those peaks from the sample that
are attributable to the multi-component analyte. Option 1 should
not be used i'f there are significant interference peaks within the
chlordane, Aroclor or toxaphene pattern.
13. PRECISION AND ACCURACY
13.1 In a single laboratory, analyte recoveries from reagent water were
used to determine analyte MDLs, EDLs (Table 3) and demonstrate
method range. Analytes were divided into two fortified groups for
recovery studies. Analyte recoveries and standard deviation about
the percent recoveries at one concentration are given in Tables 2
and 3.
13.2 In a single laboratory, analyte recoveries from two standard
synthetic ground waters were determined at one concentration level.
Results were used to demonstrate applicability of the method to
different ground water matrices. Analyte recoveries from the two
synthetic matrices are given in Table 2.
14. POLLUTION PREVENTION
14.1 This method uses significant volumes of organic solvents. It is
highly recommended that laboratories use solvent recovery systems to
recover used solvent as sample extracts are being concentrated.
Recovered solvents should be recycled or properly disposed of.
508-24
-------
14.2 For information about pollution prevention that may be applicable to
laboratory operations, consult "Less is Better: Laboratory Chemical
Management for Waste Reduction" available from the American Chemical
Society s Department of Government Relations and Science Policy
1155 16th Street N.W., Washington, D.C. 20036.
15. WASTE MANAGEMENT
15.1 It is the laboratory's responsibility to comply with all federal
state, and local regulations governing waste management, particu-
larly the hazardous waste identification rules and land disposal
restrictions. The laboratory using this method has the responsi-
bility to protect the air, water, and land by minimizing and con-
trolling all releases from fume hoods and bench operations Compli-
ance is also required with any sewage discharge permits and regula-
tions. For further information on waste management, consult "The
Waste Management Manual for Laboratory Personnel," also available
from the American Chemical Society at the address in Sect. 14.2.
16. REFERENCES
1. "Methods for the Determination of Organic Compounds in Drinking
Water, Supplement 3", (1995). USEPA, National Exposure Research
Laboratory, Cincinnati, Ohio, 45268.
2. ASTM Annual Book of Standards, Part 11, Volume 11.02 D3694-82
"Standard Practice for Preparation of Sample Containers and for
Preservation," American Society for Testing and Materials, Philadel-
phia, PA, 1986.
3. "Carcinogens - Working with Carcinogens," Department of Health
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health
Publication No. 77-206, Aug. 1977. , '
4. "OSHA Safety and Health Standards, General Industry " (29 CFR 1910)
Occupational Safety and Health Administration, OSHA 2206, (Revised
January 1976). v^cviicu,
5. "Safety in Academic Chemistry Laboratories," American Chemical
Society Publication, Committee on Chemical Safety, 3rd Edition,
6. ASTM Annual Book of Standards, Part 11, Volume 11.01, D3370-82
Standard Practice for Sampling Water," American Society for Testing
and Materials, Philadelphia, PA, 1986. y
508-25
-------
17. TABLES. DIAGRAMS. FLOWCHARTS AND VALIDATION DATA
TABLE 1. RETENTION TIMES FOR METHOD ANALYTES
Retention Time3
(minutes)
Primary Alternative
Etridiazole
Chlorneb
Propachlor
Trifluralin
HCH-alpha
Hexachlorobenzene
HCH-beta
HCH-gamma
PCNB (internal std.)
HCH-delta
Chlorthalonil
Heptachlor
Aldrin
Chlorpyrifos
DC PA
Heptachlor epoxide
Chlordane-gamina
Endosulfan I
Chlordane-alpha
4,4'-DDE
Dieldrin
Endrin
Endosulfan II
Chi orobenzi late
4,4'-DDD
Endrin aldehyde
Endosulfan sulfate
4, 4' -DDT
Methoxychlor
cis-Permethrin
trans-Permethrin
DCB
23.46
25.50
28.90
31.62
31.62
31.96
33.32
33.66
34.00
35.02
35.36
37.74
40.12
40.6
41.14
42.16
43.52
44.20
44.54
45.90
45.90
46.92
47.60
47.94
48.28
48.62
49.98
50.32
53.38
58.48
58.82
64.10
22.78
26.18
30.94
(b)
32.98
(b)
40.12
35.36
34.00
41.48
39.78
36.72
38.08
(b)
41.14
42.16
43.86
43.52
44.54
44.88
45.90
(b)
51.68
48.28
46.92
46.92
49.30
50.32
53.72
(b)
(b)
(b)
Columns and analytical conditions are described in Sect. 6.8.1 and 6.8.2,
Data not available.
508-26
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-------
TABLE 3.
SINGLE LABORATORY ACCURACY, PRECISION, METHOD DETECTION LIMITS (MDLs)
AND ESTIMATED DETECTION LIMITS (EDLs) FOR ANALYTES FROM REAGENT WATER
Aldrin
Chlordane-alpha
Chlordane-gamma
Chlorneb
Chi orobenzi late
Chlorothalonil
DC PA
4,4'-DDD
4, 4 '-DDE
4,4'~DDT
Dieldrin
Endosulfan I
Endosulfan sulfate
Endrin
Endrin aldehyde
Endosulfan II
Etridiazole
HCH-alpha
HCH-beta
HCH-delta
HCH-gamma
Heptachlor
Heptachlor epoxide
Hexachl orobenzene
Methoxychlor
cis-Permethrin
trans-Permethrin
Propachlor
Trifluralin
Fortified
Cone.
//g/L
0.075
0.015
0.015
0.50
5.0
0.025
0.025
0.025
0.010
0.060
0.020
0.015
0.015
0.015
0.025
0.015
0.025
0.025
0.010
0.010
0.015
0.010
0.015
0.0050
0.050
0.50
0.50
0.50
0.025
Na
7
7
7
7
8
7
7
7
7
7
7
7
7
7
7
7
7
8
7
7
7
7
7
7
7
7
7
7
7
Recovery %
66
117
109
47
99
119
112
115
127
87
77
78
129
72
95
148
96
94
95
84
80
67
71
115
120
64
122
90
108
RSD
; %
9
8
3
34
5
12
4
5
6
23
22
25
4
18
15
35
17
8
12
7
16
7
18
43
11
24
9
18
3
MDLb
//g/L
0.014
0.0041
0.0016
0.25
2.2
0.011
0.0032
0.0044
0.0025
0.039
0.011
0.0092
0.0024
0.0062
0.011
0.024
0.013
0.0053
0.0036
0.0020
0.0060
0.0015
0.0059
0.0077
0.022
0.25
0.18
0.25
0.0026
EDLC
//g/L
0.075
0.0015
0.0015
0.5
5.0
0.025
0.025
0.025
0.01
0.06
0.02
0.015
0.015
0.015
0.025
0.024
0.025
0.025
0.01
0.01
0.015
0.01
0.015
0.0077
0.05
0.50
0.50
0.50
0.025
508-29
-------
a N * Number of replicates
b With these data, the method detection limits (MDL) in the tables were
calculated using the formula:
MDL - S t^.-jj.gtpha . 0-99)
whsvG*
t, , , *lrJ, _ ft 00, = Student's t value for the 99% confidence level with n-1
(n"l g 1 *"3ipn3 — u»yy)
degrees of freedom.
n - number of replicates
S » standard deviation of replicate analyses.
0 EDL = estimated detection limit; defined as either MDL (Appendix B to 40 CFR
Part 136 - Definition and Procedure for the Determination of the Method
Detection Limit - Revision 1.11) or a level of compound in a sample yielding a
peak in the final extract with signal-to-noise ratio of approximately 5,
whichever value is higher.
508-30
-------
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508-31
-------
THIS PAGE LEFT BLANK INTENTIONALLY
508-32
-------
METHOD 508.1 DETERMINATION OF CHLORINATED PESTICIDES, HERBICIDES, AND
ORGANOHALIDES BY LIQUID-SOLID EXTRACTION AND ELECTRON CAPTURE
GAS CHROMATOGRAPHY
Revision 2.0
James W. Eichelberger - Revision 1.0, 1994
Jean W. Munch - Revision 2.0, 1995
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
508.1-1
-------
METHOD 508.1
DETERMINATION OF CHLORINATED PESTICIDES, HERBICIDES, AND
ORGANOHALIDES IN WATER USING LIQUID-SOLID EXTRACTION
AND ELECTRON CAPTURE GAS CHROMATOGRAPHY
1. SCOPE AND APPLICATION
1.1 This method utilizes disk liquid-solid extraction and gas
chromatography with an electron capture detector to determine twenty
nine chlorinated pesticides, three herbicides, and four
organohalides in drinking water, ground water, and drinking water in
any treatment stage. Liquid solid extraction cartridges may also be
used to carry out sample extractions. Single laboratory accuracy,
precision, and method detection limit data have been determined for
the following compounds:
Analvte
Alachlor
Aldrin
Atrazine
Butachlor
Chlordane-alpha
Chlordane-gamma
Chloroneb
Chiorbenzilate
Chlorthalonil
Cyanazine
DC PA
4,4'-DDD
4,4'-DDE
4,4'-DDT
Dieldrin
Endosulfan I
Endosulfan II
Endosulfan sulfate
Endrin
Endrin aldehyde
Etridiazole
HCH-alpha
HCH-beta
HCH-delta
HCH-gamma (lindane)
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Hexachlorocyclopentadi ene
Methoxychlor
Metolachlor
Metribuzin
Chemical Abstracts
Service Registry No.
15972
309
1912
23184
5103
5103
2675
510
1897
21725
1861
72
72
50-
60-
959-
33213-
1031-
.72-
7421-
2593-
319-
319-
319-
58-
76-
1024-
118-
77-
72-
51218-
21087-
-60-8
-00-2
-24-9
-66-9
-71-9
-74-2
-77-6
-15-6
-45-6
-46-2
-32-1
•54-8
•55-9
•29-3
•57-1
•98-8
•65-9
07-8
20-8
93-4
15-9
84-6
85-7
86-8
89-9
44-8
57-3
74-1
47-4
43-5
45-2
64-9
508.1-2
-------
Chemical Abstracts
Analyte Service Registry No.
cis-Permethrin
trans-Permethrin
Propachlor
Simazine
Toxaphene
Trifluralin
Aroclor 1016
Aroclor 1221
Aroclor 1232
Aroclor 1242
Aroclor 1248
Aroclor 1254
Aroclor 1260
54774-45-7
51877-74-8
1918-16-7
122-34-9
8001-35-2
1582-09-8
12674-11-1
11104-28-2
11141-16-5
53469-21-9
12672-29-6
11097-69-1
11096-82-5
1.2 This method has been validated in a single laboratory and method
detection limits have been determined for each analyte listed above
The method detection limit (MDL) is defined as the statistically
calculated minimum amount that can be measured with 99% confidence
that the reported value is greater than zero (1). For the listed
analytes (except multi-component analytes), MDLs which range from
0.001 /ig/L to 0.015 ng/L are listed in Table 3. MDLs for multi-
component analytes (Aroclors and toxaphene) range from 0.01 to 0 13
2. SUMMARY OF METHOD
2.1 The analytes are extracted from the water sample by passing 1 L of
sample through a preconditioned disk or cartridge containing a solid
inorganic matrix coated with a chemically bonded C18 organic phase
(liquid-solid extraction,. LSE). The analytes are eluted from the
LSE disk or cartridge with small volumes of ethyl acetate and
methylene chloride, and this eluate is concentrated by evaporation
of some of the solvent. The sample components are separated,
identified, and measured by injecting micro-liter quantities of the
eluate into a high resolution fused silica capillary column of a gas
chromatograph/electron capture detector (GC/ECD) system.
3. DEFINITIONS
3.1 INTERNAL STANDARD (IS) -- A pure analyte(s) added to a sample,
extract, or standard solution in known amount(s) and used to measure
the relative responses of other method analytes and surrogates that
are components of the same solution.
3.2 SURROGATE ANALYTE (SA) - A pure analyte(s), which is extremely
unlikely to be found in any sample, and which 'is added to a sample
aliquot in known amount(s) before extraction or other processing,
and is measured with the same procedures used to measure other
sample components. The purpose of the SA is to monitor method
performance with each sample.
508.1-3
-------
3.3 LABORATORY REAGENT BLANK (LRB) — A aliquot of reagent water or
other blank matrix that is treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents, internal
standards, and surrogates that are used with other samples. The LRB
is used to determine if method analytes or other interferences are
present in the laboratory environment, the reagents, or the
apparatus.
3.4 INSTRUMENT PERFORMANCE CHECK SOLUTION (IPC) — A solution of one or
more method analytes, surrogates, internal standards, or other test
substances used to evaluate the performance of the instrument system
with respect to a defined set of method criteria.
3.5 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water or
other blank matrix to which known quantities of the method analytes
are added in the laboratory. The LFB is analyzed exactly like a
sample, and its purpose is to determine whether the methodology is
in control, and whether the laboratory is capable of making accurate
and precise measurements.
3.6 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
3.7 STOCK STANDARD SOLUTION (SSS) — A concentrated solution containing
one or more method analytes prepared in the laboratory using assayed
reference materials or purchased from a reputable commercial source.
3.8 PRIMARY DILUTION STANDARD SOLUTION (PDS) — A solution of several
analytes prepared in the laboratory from stock standard solutions
and diluted as needed to prepare calibration solutions and other
needed analyte solutions.
3.9 QUALITY CONTROL SAMPLE (QCS) — A solution of method analytes of
known concentrations which are used to fortify an aliquot of LRB or
sample matrix. The QCS is obtained from a source external to the
laboratory and different from the source of calibration standards.
It is used to check laboratory performance with externally prepared
test materials.
3.10 METHOD DETECTION LIMIT (MDL) — The statistically calculated minimum
amount of an analyte that can be measured with 99% confidence that
the reported value is greater than zero (1).
INTERFERENCES
4.1 Method interferences may be caused by contaminants in solvents,
reagents, glassware, and other sample processing apparatus that lead
to anomalous peaks or elevated baselines in gas chromatograms.
508.1-4
-------
4.2 Interfering contamination may occur when a sample containing low
concentrations of compounds is analyzed immediately after a sample
containing relatively high concentrations of compounds. -Syringes
and splitless injection port liners must be cleaned carefully or
replaced as needed. After analysis of a sample containing high
concentrations of compounds, a laboratory reagent blank should be
analyzed to ensure that accurate values are obtained for the next
sample.
4.3 It is important that samples and standards be contained in the same
solvent, i.e., the solvent for final working standards must be the
same as the final solvent used in sample preparation. If this is
not the case, chromatographic comparability of standards to sample
may be affected.
5. SAFETY
5.1 The toxicity or carcinogenicity of each chemical and reagent used in
this method has not been precisely defined. .However, each one must
be treated as a potential health hazard, and exposure to these
chemicals should be minimized. Each laboratory is responsible for •
maintaining a current awareness of OSHA regulations regarding safe
handling of the chemicals used in this method. Additional
references to laboratory safety are cited (2-4).,
5.2 Some method analytes have been tentatively classified as known or
suspected human or mammalian carcinogens. Pure standard materials
and stock standard solutions of these compounds should be handled
with suitable protection to skin, eyes, etc.
6. EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers and brand names are included for illustration only.)
6.1 All glassware, including sample bottles, must be meticulously
cleaned. This may be accomplished by washing with detergent and
water, rinsing with tap water, distilled water, or solvent, air-
drying, and heating (where appropriate) in a muffle furnace for two
hours at 400°C. Volumetric glassware must never be heated in a
muffle furnace.
6.2 SAMPLE CONTAINERS — 1-L or 1-quart amber glass bottles fitted with
Teflon-lined screw caps. Amber bottles are highly recommended since
some of the method analytes are sensitive to light and are oxidized
or decomposed upon exposure.
6.3 VOLUMETRIC FLASKS — Various sizes.
6.4 MICRO-SYRINGES — Various sizes.
6.5 VIALS -- Various sizes of amber vials with Teflon-lined screw caps.
6.6 DRYING COLUMN — The drying tube should contain about 5 to 7 grams
of anhydrous sodium sulfate to prohibit residual water from
contaminating the extract. Any small tube may be used, such as a
508.1-5
-------
syringe barrel, a glass dropper, etc., as long as no sodium sulfate
passes through the column into the extract.
6.7 FUSED SILICA CAPILLARY GAS CHROMATOGRAPHY COLUMN — Any capillary
column that provides adequate resolution, capacity, accuracy, and
precision may be used. A 30 m X 0.25 mm ID fused silica capillary
column coated with a 0.25 jan bonded film of polyphen'yl methyl si li cone
(J&W DB-5) was used to develop this method. Any column which
provides analyte separations equivalent to or better than this
column may be used.
6.8 GAS CHROMATOGRAPH — Must be capable of temperature programming, be
equipped for split/splitless injection, and be equipped with an
electron capture detector. On-column capillary injection is
acceptable if all the quality control specifications in Sect. 9 and •
Sect. 10 are met. The injection system should not allow the
analytes to contact hot stainless steel or other hot metal surfaces
that promote decomposition.
6.9 VACUUM MANIFOLD — A manifold system or a commercially available
automatic or robotic sample preparation system designed for disks or
cartridges should be utilized in this method. Ensure that all
quality control requirements discussed in Sect. 9 are met. A
standard all glass or Teflon lined filter apparatus should be used
for disk or cartridge extraction when an automatic system is not
utilized.
7. REAGENTS AND STANDARDS
7.1 HELIUM CARRIER GAS — As contaminant free as possible.
7.2 EXTRACTION DISKS AND CARTRIDGES - Containing octadecyl bonded silica
uniformly enmeshed in an inert matrix. The disks used to generate
the data in this method were 47 mm in diameter and 0.5 mm in
thickness. Larger disk sizes are acceptable. The disks should not
contain any organic compounds, either from the matrix or the bonded
silica, that will leach into the ethyl acetate and methylene
chloride eluant. Cartridges should be made of inert, non-leaching
plastic or glass, and must not leach plasticizers or other organic
compounds into the eluting solvent. Cartridges contain about 1 gram
of silica or other inert inorganic support whose surface is modified
by chemically bonding octadecyl C18 groups.
7.3 SOLVENTS — Methylene chloride, ethyl acetate, and methanol, high
purity pesticide quality or equivalent.
7.4 REAGENT WATER — Water in which an interferant is not observed at
the MDL of the compound of interest. Prepare reagent water by
passing tap or distilled water through a filter bed containing
activated carbon, or by using-a water purification system. If
necessary, store reagent water in clean bottles with Teflon-lined
screw caps.
7.5 HYDROCHLORIC ACID — 6N.
508.1-6
-------
7.6 SODIUM SULFATE — Anhydrous, muffled at 400°C for a minimum of 4 hrs
and stored in an air-tight clean glass container at ambient
temperature.
7.7 SODIUM SULFITE — Anhydrous. .
7.8 PENTACHLORONITROBENZENE - > 98% purity, for use as the internal
standard.
7.9 4,4-DIBROMOBIPHENYL — > 96% purity, for use as the surrogate
compound.
7.10 STOCK STANDARD SOLUTIONS — Individual solutions of analytes may be
purchased;from commercial suppliers or prepared from pure materials.
These solutions are usually available at a concentration of 500
Mg/mL. These solutions are used to make the primary dilution
standard. They should be stored in amber vials in a refrigerator or
freezer. Stock standard solutions should be replaced if ongoing
quality control checks indicate a problem.
7.11 PRIMARY DILUTION STANDARDS - Prepare the solution(s) to contain
all method analytes, but not the internal standard or surrogate
compound, at a concentration of 2.5 /ig/mL in ethyl acetate.
7.12 INSTRUMENT PERFORMANCE CHECK SOLUTION -- Prepare by accurately
weighing 0.0010 g each of chlorothalonil, chlorpyrifos, DCPA, and
HCH-delta. Dissolve each analyte in MTBE and dilute to volume in
individual 10-mL volumetric flasks. Combine Zjjl of the chlorpyrifos
stock solution, 50 //L of the DCPA stock solution, 50/yL of the
chlorothalonil stock solution, and 40//L of the HCH-delta stock
solution to a 100-mL volumetric flask and dilute to volume with
ethyl acetate. Transfer to a TFE-fluorocarbon-sealed screw cap
bottle and store at room temperature. Solution should be replaced
when ongoing QC (Section 9) indicates a problem.
7.13 CALIBRATION SOLUTIONS - Using the primary dilution standards,
prepare calibration solutions at six concentrations in ethyl
acetate. The calibration range is dependent upon the
instrumentation used, and expected analyte concentrations in the
samples to be analyzed. A suggested concentration range of
calibration solutions is 0.002-1.0 fjg/ml. Note: Calibration
standards for toxaphene and each of the Aroclors must be prepared
individually..
7.14 INTERNAL STANDARD SOLUTION — Prepare this solution of
pentachloronitrobenzene by itself in ethyl acetate at a
concentration of 10 jjg/ml.
7.15 SURROGATE COMPOUND SOLUTION — Prepare this solution of 4,4'-
dibromobiphenyl by itself in ethyl acetate at a concentration of 10
jt/g/mL. Other surrogate compounds may be used if it can be
demonstrated that they are not in any samples and are not interfered
with by any analyte or other sample component.
508.1-7
-------
7.16 GC DEGRADATION CHECK SOLUTION — Prepare a solution in ethyl acetate
\ containing endrin and 4,4'-DDT each at a concentration of 1 ng/ml.
This solution will be injected to check for undesirable degradation
of these compounds in the injection port by looking for endrin
aldehyde and endrin ketone or for 4,4'- DDE and 4,4'- ODD.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 When sampling from a water tap, open the tap and allow the system to
flush until the water temperature has stabilized (generally 1-2
min). Adjust the flow to about 500 mL/min and collect the sample
from the flowing stream. Keep sample sealed from collection time
until analysis. When sampling from a body of water, fill the sample
container with water from a representative area. Sampling
equipment, including automatic samplers, must not use plastic
tubing, plastic gaskets, or any parts that may leach interfering
analytes into the sample. Automatic samplers that composite samples
over time should use refrigerated glass sample containers.
8.2 Residual chlorine in the sample should be reduced by adding 50 mg/L
of sodium sulfite (this may be added as a solid with stirring or
shaking until dissolved, or as a prepared solution).
8.3 Adjust the sample to pH <2 by adding 6N HC1. It may require up txr 4
ml to accomplish this. It is very important that the sample be
dechlorinated (Sect. 8.2) before adding the acid to lower the pH of
the sample. Adding sodium sulfite and HC1 to the sample bottles
prior to shipping the bottles to the sampling site is not permitted.
HC1 should be added at the sampling site to retard any
microbiological degradation of method analytes.
8.4 Samples must be iced or refrigerated at 4°C from the time of
collection until extraction. Preservation study results show that
the analytes (except cyanazine) are stable for 14 days in samples
that are preserved as described in Sect. 8.2 and Sect. 8.3.
Refrigerated sample extracts may be stored up to 30 days.
8.5 If cyanazine is to be determined, a separate sample must be
collected. Cyanazine degrades in the sample when it is stored under
acidic conditions or when sodium sulfite is present in the stored
sample. Samples collected for cyanazine determination MUST NOT be
dechlorinated or acidified when collected. They should be iced or
refrigerated as described above and analyzed within 14 days.
However, these samples must be dechlorinated and acidified
immediately prior to fortification with the surrogate standard and
extraction using the same quantities of acid and sodium sulfite
described above.
9. QUALITY CONTROL
9.1 Quality control requirements are the initial demonstration of
laboratory capability followed by regular analyses of laboratory
reagent blanks, laboratory fortified blanks, and laboratory
fortified matrix samples. The laboratory must maintain records to
508.1-8
-------
document the quality of the data generated. .Additional quality
control practices are recommended. Determination of a MDL is also
required.
9.2 Before any samples are analyzed or any time a new supply of disks or
cartridges are received from a supplier, it must be demonstrated
that a laboratory reagent blank is reasonably free of contamination
that would prevent the determination of any analyte of concern.
Both disks and cartridges could contain trace quantities of
phthalate esters or silicon compounds that could prevent the
determination of method analytes at low concentrations. Other
sources of background contamination are impure solvents, impure
reagents, and contaminated glassware. In general, background from
method analytes should be below method detection limits.
9.3 INITIAL DEMONSTRATION OF CAPABILITY
9.3.1 To demonstrate initial laboratory capability, analyze a
minimum of four replicate laboratory fortified blanks
containing each analyte of concern at a suggested
concentration in the range of 0.01-0.5 ng/L. Prepare each
reagent water replicate by adding sodium sulfite (Sect. 8.2)
and HC1 (Sect. 8.3) to each sample, then adding an
appropriate aliquot of the primary dilution standard
solution(s). Analyze each replicate according to the
procedures described in Sect. 11.
9.3.2 Calculate the measured concentration of each analyte in each
replicate, the mean concentration of each analyte in all
replicates, the mean accuracy (as mean percentage of true
value) for each analyte, and the precision (as relative
standard deviation, RSD) of the measurements for each
analyte.
9.3.3 For each analyte, the mean accuracy, expressed as a
, percentage of the true value, should be 70-130% and the RSD
should be < 30%.
9.3.4 To determine the MDL, analyze a minimum of seven replicate
laboratory fortified blanks which have been fortified with
all analytes of interest at approximately 0.01 ng/L (Use a
higher concentration for multi-component analytes).
Calculate the MDL of each analyte using the procedure
described in Sect. 13.2 (1). It is recommended that these
analyses be carried out over a period of three or four days
to produce more realistic limits.
9.3.5 .Develop a system of control charts to plot the precision and
accuracy of analyte and surrogate compound recoveries as a
function of time. Charting of surrogate compound recoveries,
which are present in every sample, will form a significant
record of data quality. When surrogate recovery from a
sample, a LFB, or a LFM is <70% or >130%, check calculations
to locate possible errors, the fortifying solution for
. . degradation, and changes in instrument performance. If the
508.1-9
-------
cause cannot be determined, reanalyze the sample. If the
surrogate recovery from an LFB is still is <70% or >130%,
remedial action (Sect. 10.8) will likely be necessary. If
the surrogate recovery from a field sample or LFM is still is
<70% or >130%, and LFBs are in control, a matrix effect is
suspected.
9.4 Assessing the Internal Standard. The analyst should monitor the
internal standard response (peak area units) of all samples and LFBs
during each work shift. The IS area should not deviate from the
latest continuing calibration check (Sect. 10.7) by more than 30%,
or from the initial calibration by more than 50%. If this criteria
cannot be met, remedial action (Sect. 10.8) must be taken. When
method performance has been restored, reanalyze any extracts that
failed Sect. 9.4 criteria.
9.5 With each group or set of samples processed within a 12 hr work
shift, analyze a LRB to determine background contamination. Any
time a new batch of LSE disks or cartridges are received, or a new
supply of reagents are used, repeat Sect. 9.2.
9.6 Assessing Laboratory Performance. With each group or set of samples
processed within a 12 hr work shift, analyze a LFB containing each
analyte of interest at a concentration of 0.01 to 0.5 /Kj/L. If more
than 20 samples are included in a set, analyze a LFB for every 20
samples. Use the criteria in Sect. 9.3.3 to evaluate the accuracy
of the measurements. If acceptable accuracy cannot be achieved, the
problem must be located and corrected before additional samples are
analyzed. Maintain control charts to document data quality.
Note: It is suggested that one multi-component analyte (an Aroclor
or toxaphene) LFB also be analyzed with each sample set. By
selecting a different multi-component analyte for this LFB each work
shift, LFB data can be obtained for all of these analytes over the
course of several days.
9.7 Assessing Sample Matrix Effects. In an attempt to ascertain any
detrimental matrix effects, analyze a LFM for each type of matrix
(i.e. tap water, ground water, surface water). This need not be
done with every group of samples unless matrices are vastly
different. The LFM should contain each analyte of interest at a
concentration similar to that selected in Sect. 9.6. Results from a
LFM should be within 65-135% of the fortified amount. If these
criteria are not met, then a matrix interference is suspected and
must be documented.
9.8 Assessing Instrument Performance. Instrument performance should be
monitored each 12 hr work shift by analysis of the IPC sample and GC
degradation check solution.
9.8.1 The IPC sample contains compounds designed to indicate
appropriate instrument sensitivity, column performance
(primary column) and chromatographic performance. IPC sample
components and performance criteria are listed in Table 2.
508.1-10
-------
Inability to demonstrate acceptable instrument performance
indicates the need for revaluation-of-the instrument system.
9.8.2 Inject the GC degradation check solution. Look for the
degradation'products of 4,4'-DDT (4,4'-DDE and 4,4'-DDD) and
the degradation products of endrin (endrin aldehyde, EA and
endrin ketone, EK). For 4,4'-DDT, these products will elute
•just before the parent, and for endrin, the products will
elute just after the parent. If degradation of either DDT or
endrin exceeds 20%, resilanize the injection port liner
and/or break off a meter from the front of the column. The
degradation check solution is required in each 12 hr
workshift in which analyses are performed.
% degrade
of 4,4'DDT
% degrade
of endrin
Total DDT degradation peak area (DDE+DDD)
Total DDT peak area (DDT+DDE+DDD)
X100
Total EA + EK peak area
Total endrin+EA+EK area
X100
NOTE: If the analyst can verify that 4,4 DDT, endrin, their
breakdown products, and the analytes in the IPC solution are
all resolved, the IPC solution and the GC degradation check
solution may be prepared and analyzed as a single solution.
9.9 At least quarterly, analyze a QCS from an external source. If
measured analyte concentrations are not of acceptable accuracy as
described in Sect. 9.3.3, check the entire analytical procedure to
locate and correct the problem.
9.10 Numerous other quality control measures are incorporated into other
parts of this method, and serve to alert the analyst to potential "
problems.
10. CALIBRATION AND STANDARDIZATION
10.1 Demonstration and documentation of acceptable initial calibration
are required before any samples are analyzed and is required
intermittently throughout sample analysis as dictated by results of
continuing calibration checks. After initial calibration has been
successfully accomplished, at least one continuing calibration check
is required each 12 hr work shift in which analyses are performed.
10.2 Establish GC operating parameters equivalent to those below:
Injector temperature —
Detector temperature --
Injection volume
Temperature program --
250°C
320°C
2 jtiL, split!ess- for 45 sec.
Inject at 40°C and hold 1 min.
program at 20°C/min. to 160°C hold 3 min.
program at 3°C/min. to 275°C with no hold
program at 20°C/min. to 310°C with no hold
Using the above conditions and the column in Sect. 6.7, the total
run time is about 50 min. The last eluting analyte is trans-
508.1-11 .
-------
permethrin which elutes at 267°C with a retention time of 45.4 min.
Table 1 lists all method analytes and their retention times using
the above conditions, ft should be noted that some method analytes
elute very close together. If there are unresolved peaks using the
above temperature program, the analyst should modify the program to
achieve resolution.
10.3 Analyze the instrument performance check sample and GC degradation
check sample, and evaluate as described in Sect. 9.8. If acceptance
criteria are met, proceed with calibration. If criteria are not
met, take remedial action (Sect. 10.8).
10.4 Prepare calibration solutions containing all analytes of interest
according to Sect. 7.13 in ethyl acetate. The calibration standard
concentrations should bracket the expected concentration range of
each analyte in sample extracts, or define the working range of the
detector. Each standard must contain the internal standard,
pentachlordnitrobenzene, at a concentration of 0.5 /zg/.mL. The
surrogate should also be present in each solution at that
concentration.
Note: Calibration standards of multi-component analytes must be
prepared and analyzed as separate solutions
10.5 Analyze each calibration standard using the suggested
conditions in Sect. 10'.2. Tabulate peak area versus
concentration for each compound and the internal standard.
Calculate the response factor (RF) for each analyte and
the surrogate using the following equation.
where: As = response for the analyte to be measured
AIS = response for the 'internal standard
CIS = concentration of the internal standard (/ig/mL)
C = concentration of the analyte to be measured
Note: To calibrate for multi-component analytes, one of the
following methods should be used.
Option 1- Calculate an average response factor or linear regression
equation for each multi-component analyte using the combined area of
all the component peaks in each of the calibration standard
chromatograms.
Option 2- Calculate an average response factor or linear regression
equation for each multi-component analyte using the combined areas
of 3-6 of the most intense and reproducible peaks in each of the
calibration standard chromatograms.
10.6 If the RF over the working range is constant (<30% RSD), the average
RF can be used for calculations. Alternatively, use the results to
generate a linear regression calibration for each analyte using
response ratios (AS/AIS) vs. Cs.
508.1-12
-------
10.7 The linear regression calibration or RF must be verified on each
work shift (not to exceed 12 hrs) by measuring .one or more
calibration standards. Additional periodic calibration checks are
good laboratory practice. It is highly recommended that an
additional calibration check be performed at the end of any cycle of
continuous instrument operation, so that each set of field samples
is bracketed by calibration check standards. Varying the
concentration of continuing calibration standards from shift to
shift is recommended, to evaluate the accuracy of the calibration at
more than one point. Calculate the RF for each analyte from the
data measured in the continuing calibration check. The RF for each
analyte must be within 30% of the mean value measured in the initial
calibration. If a linear regression calibration is being used, the
measured amount for each analyte from the calibration verification
test must be within 30% of the true value. If these conditions do
not exist, remedial action should be taken which may require
recalibration. For those analytes that failed the calibration
verification, results from field samples analyzed since the last
passing calibration should be considered suspect. Reanalyze sample
extracts for these analytes after acceptable calibration is
restored.
V
Note:-It is suggested that a calibration verification standard of
one multi-component analyte (an Aroclor or toxaphene)'also be
analyzed each work shift. By selecting a different multi-component
analyte for this calibration verification each work shift,
continuing calibration data can be obtained for all of these
analytes over the course of several days.
10.8 The,fol1 owing are suggested remedial'actions which may improve
method performance:
10.8.1 Check and adjust GC operating conditions and temperature
programming parameters.
10.8.2 Clean or replace the splitless injector liner. Silanize a
cleaned or new liner.
10.8.3 Break off a short portion of the GC column from the end near
the injector, or replace GC column. Breaking off a portion
of the column will somewhat shorten the analyte retention
times.
10.8.4 Prepare fresh calibration solutions and repeat the initial
calibrations.
10.8.5 Replace any components in the GC that permit analytes to come
in contact with hot metal surfaces.
11. PROCEDURE
11.1 DISK EXTRACTION
11.1.1 This procedure may be carried out in the manual mode or in
the automatic mode using a robotic or automatic sample
508.1-13
-------
preparation device. If an automatic system is used to
prepare samples, follow the manufacturer's instructions, but
follow this procedure. If the manual mode is used, the setup
of the extraction apparatus described in EPA Method 525.2 (5)
may be used.
This procedure was developed using the standard 47 mm
diameter disks. Larger disks (i.e. 90 mm) may be used if
special matrix problems are encountered. If larger disks are
used, the washing solvent volume is 15 ml and the elution
solvent volumes are two 15 ml aliquots.
11.1.2 Insert the disk into the filter apparatus or sample
preparation unit. Wash the disk with 5 ml of a 1:1 mixture
of ethyl acetate (EtAC) and methylene chloride (MeCl2) by
adding the solvent to the disk, then drawing it through very
slowly to ensure adequate contact time between solvent and
disk. Soaking the disk may not be desirable when disks other
than Teflon are used.
11.1.3 Add 5 mL methanol to the disk and draw some of it through
slowly. A layer of methanol must be left on the surface of
the disk which must not be allowed to go dry from this point
until the end of the sample extraction. THIS IS CRITICAL FOR
UNIFORM FLOW AND GOOD ANALYTE RECOVERIES.
11.1.4 Rinse the disk with 5 mL reagent water by adding the water to
the disk and drawing most through, again leaving a layer on
the surface of the disk.
11.1.5 Add 5 mL methanol to the sample and mix well. Mark the water
meniscus on the side of the sample bottle for later
determination of sample volume.
11.1.6 Add 50 jiiL of the surrogate compound solution (Sect. 7.15) and
shake well.
11.1.7 Draw the sample through the disk while maintaining sufficient
vacuum. One liter of drinking water may pass through the
disk in as little as 5 min without reducing analyte
recoveries. Drain the entire sample from the container
through the disk. Determine the original sample volume by
refilling the sample bottle to the mark with tap water and
transferring the water to a 1000-mL graduated cylinder.
Measure to the nearest 5 mL. • .
11.1.8 Dry the disk by drawing air or nitrogen through the disk for
about 10 min.
11.1.9 Remove the filtration glassware, but do not disassemble the
reservoir and fritted base. Insert a collection tube into
the vacuum manifold. If a suction flask is being used, empty
the water-from the flask and insert a suitable collection
. tube to contain the eluate. The only constraint on the
collection tube is that it fit around the drip tip of the
fritted base. Reassemble the apparatus.
508.1-14
-------
11.1.10 Rinse the inside walls of the sample bottle with 5 mL EtAC
then transfer the solvent to the disk using a syringe or
disposable pipet. Rinse the inside walls of the glass
filtration reservoir with this EtAC. Draw the solvent
through the disk very slowly to allow adequate contact time
between disk and solvent for good analyte recoveries.
.11.1.11 Repeat the above step (Sect. 11.10) with 5 ml MeCl2.
11.1.12 Using the syringe or disposable pipet, ri.nse the filtration
reservoir with two 3 ml portions of 1:1 EtAc:MeCl2. Pour all
combined eluates through the drying tube containing about 5
to 7 grams of anhydrous sodium sulfate. Rinse the drying
tube and the sodium sulfate with two 3 ml portions of 1:1
EtAc/MeCl2. Collect all eluate and washings in a
concentrator tube.
11.1.13 Concentrate the extract to approximately 0.8 ml under a
gentle stream of nitrogen while warming gently in a water
bath or heating block. Rinse the inside walls of the
concentrator tube two or three times with EtAC during
concentration. Fortify the extract with 50 /zL of the IS
fortifying solution (Section 7.14). Adjust.the extract
volume to 1.0 ml with EtAc. •
11.1.14 Inject a 1 or 2 /uL aliquot into the gas chromatograph using
the GC conditions used for initial calibration (Sect. 10.2).
Table 1 lists retention times for method'analytes using these
conditions.
11.1.15 Identify a method analyte in the sample extract by comparing
its gas chromatographic retention time to the retention time.
of the known analyte in a reference standard chromatogram, a
calibration standard, or a laboratory fortified blank. If
the retention time of the sample peak is within the pre-
defined retention time window, identification is considered
positive. The width of the retention time window used to
make identifications should be based on measurements of
actual retention time variations of standards during the
course of a work shift. It is suggested that three times the
standard deviation of the retention times obtained when the
system is calibrated be used to calculate the window. The
experience of the analyst should be an important factor in
the interpretation of a gas chromatogram. Confirmation may
be performed by analysis on a second column, or if
concentrations are sufficient, by GC/MS.
Note: Identify multi-component analytes by comparison of the
sample chromatogram to the corresponding calibration standard
chromatograms of toxaphene and the Aroclors. Identification
of multi-component analytes is made by pattern recognition,
in which the experience of the analyst is an important
factor. Figures 1-8 illustrate patterns that can be expected
from these analytes at low concentrations. The peaks
indicated on the chromatograms are those that were used for
508.1-15
-------
quantitation. Other peaks may be selected at the discretion
of the analyst.
11.2 CARTRIDGE EXTRACTION
11.2.1 This procedure may be carried out in the manual mode or in
the automatic mode using a robotic or automatic sample
preparation device. If an automatic system is used to
prepare samples, follow the manufacturer's instructions, but
follow this procedure. If the manual mode is used, the setup
of the extraction apparatus described in EPA Method 525.2 (5)
may be used.
11.2.2 Elute each cartridge with a 5 ml aliquot of ethyl acetate
followed by a 5 ml aliquot of methylene chloride. Let the
cartridge drain dry after each flush. Then elute the
cartridge with a 10 mL aliquot of methanol, but DO NOT allow
the methanol to elute below the top of the cartridge packing.
Add 10 mL of reagent water to the cartridge and elute, but
before the reagent water level drops below the top edge of
the packing, begin adding sample to the solvent reservoir.
11.2.3 Pour the water sample into the 2-L separatory funnel with the
stopcock closed, add 5 mL methanol and the surrogate
standard, and mix well. If a vacuum manifold is used instead
of the separatory funnel, the sample may be transferred
directly to the cartridge after the methanol and surrogate
standard are added to the sample.
11.2.4 Drain the sample into the cartridge being careful not to
overflow the cartridge. Maintain the packing material in the
cartridge immersed in water at all times. After all the
sample has passed through the LSE cartridge, draw air or
nitrogen through the cartridge for 10 min.
11.2.5 If the setup in Method 525.2 (5) is being used, transfer the
125 mL solvent reservoir and LSE cartridge to the elation
apparatus. The same reservoir is used for both apparatus.
Rinse the inside of the separatory funnel and the sample jar
with 5 mL ethyl acetate and elute the cartridge with this
rinse into the collection tube. Wash the inside of the
separatory funnel and the sample jar with 5 mL methylene
chloride and elute the cartridge, collecting the rinse in the
same collection tube. Small amounts of residual water from
the sample container and the LSE cartridge may form am
immiscible layer with the eluate. Pass the eluate through the
drying column which is packed with approximately 5 to 7 grams
of anhydrous sodium sulfate and collect in a second tube.
• Wash the sodium sulfate with at least 2 mL methylene chloride
and collect in the same tube. Proceed according to steps in
Sect. 11.1.13, 11.1.14 and Sect. 11.1.15 above.
508.1-16
-------
12. DATA ANALYSIS AND CALCULATIONS
12.1 Calculate the concentration (C) of the analyte in the sample using
the response factor (RF) determined in Sect. 10.5 and the equation
below.
(As) (Is)
C (/ig/L) =
(AIS)(RF)(V0)
where: As = peak area for the analyte to be measured
AjS = peak area for the internal standard
Is = amount of internal standard added (/ig)
V0 = volume of water extracted (L)
If a linear regression calibration is used, use the regression
equation to calculate the amount of analyte in the sample. All
samples containing analytes.outside the calibration range must be
diluted and reanalyzed. When diluting, add additional internal
standard to maintain its concentration at 0.5 jjg/ml in the diluted
extract.
12.2 To quantitate multi-component analytes, one of'the following methods
should be used.
Option 1- Calculate an average response factor or linear regression
equation for each multi-component analyte using the combined area of
all the component peaks in each of the calibration standard
chromatograms.
Option 2- Calculate an average response factor or linear regression
equation for each multi-component analyte using the combined areas
of 3-6 of the most intense and reproducible peaks i.n each of the
calibration standard chromatograms.
When quantifying multi-component analytes in samples, the analyst
should use caution to include only those peaks from the sample that
are attributable to the multi-component analyte. Option 1 should
not be used if there are significant interference peaks within the
Aroclor or toxaphene pattern.
13. METHOD PERFORMANCE
13.1 Method performance data was obtained using the GC column and
conditions described in Sections 6.7 and 10.2. Retention times are
listed in Table 1. All data presented here were obtained with the
liquid-solid extraction disk option. Previous method development
research has shown no significant performance differences between
cartridges and disks. Method 525.2 shows comparative recovery data
for Method 508.1 analytes using both cartridges and disks.
13.2 Method detection limits (MDL) for all method analytes (except
Aroclors and toxaphene) were determined by analyzing seven reagent
water samples which were fortified with the analytes at a
concentration of 0.01 /ig/L. The mean and standard deviation were
calculated for each analyte. The MDL was calculated by multiplying
the standard deviation by the students-t value for n-l-and a 99%
508.1-17
-------
confidence interval (1). The students-t value for seven replicates
(n-l=6) is 3.143. The mean recoveries and the standard deviations
along with the MDLs are listed in Table 3. Aroclor and toxaphene
data in Table 3 were calculated using Option 2 in Section 12.2.
13.3 Method accuracy and precision were determined by analyzing two sets
of eight reagent water samples fortified with method analytes .
(except the multi-component analytes) at approximately 5 and 10
times the average MDL. The fortification concentrations for these
samples were calculated by averaging the analyte MDLs and
multiplying that average by 5 and 10. Thus the concentrations used
were 0.03 /ig/L and 0.048 jug/L. Results of these analyses are listed
in Tables 4 and 5. An additional set of samples was analyzed at
approximately 20 times the average MDL (0.096/zg/L). This set of
samples was extracted from an artificial matrix containing Img/L
fulvic acid. The fulvic acid served to mimic the naturally
occurring organic material found in many water sources. The results
of these analyses are listed in Table 6.
13.4 Atrazine, hexachlorocyclopentadiene, and metribuzin appear to be
problem analytes. Atrazine displays low peak response when compared
to most of the other method analytes, and requires manual peak area
integration even at the 0.048-/ig/L level.
Hexachlorocyclopentadiene, while displaying relatively high peak
response, showed poor recovery. The resulting mean recoveries were
50.8, 52.6, and 21.7 percent respectively for the three levels. It
is suspected that the higher volatility of hexachlorocyclopentadiene
causes the problem. Very careful, very slow nitrogen blowdown may
produce higher recoveries of this compound (5).
It is suspected that Metribuzin was recovered poorly due to
breakthrough on C-18 media (5).
14. POLLUTION PREVENTION
14.1 This method utilizes liquid-solid extraction (LSE) technology to
remove the analytes from water. It requires the use of very small
volumes of organic solvent and very small quantities of pure
analytes. This eliminates the potential hazards to both the analyst
and the environment that are present when large volumes of solvents
are used in conventional liquid-liquid 'extractions.
14.2 For information about pollution prevention that may be applicable to
laboratory operations, consult "Less Is Better: Laboratory Chemical
Management for Waste Reduction" available from the American Chemical
Society's Department of Governmental Relations and Science Policy,
1155 16th Street N.W., Washington, D.C., 20036.
15. WASTE MANAGEMENT
15.1 It is the laboratory's responsibility to comply with all federal,
state, and local regulations governing waste management,
particularly the hazardous waste identification rules and land
disposal restrictions. The laboratory using this method has the
responsibility to protect the air, water, and land by minimizing and
controlling all releases from fume hoods and bench operations.
508.1-18
-------
Compliance is .also .required with any sewage discharge permits and
. regulations. For further information on waste management, consult
.•:.;. "The Waste, Management Manual for Laboratory Personnel," also
available from the .American Chemical Society at the address in Sect,
14.2.
16. REFERENCES
1. , J.A. Glaser, D..L. Foerst, G.D. McKee, S.A. Quave, and W.L. Budde,
"Trace Analyses for Wastewaters," Environ. Sci. Technol. 1981 15,
1426-1435. or 40 CFR, Part 136, Appendix B.
2. "Carcinogens - Working With Carcinogens," Department of Health,
Education,, and Welfare, Public Health Service, Center for Disease
Control., National Institute for Occupational Safety and Health,
Publication No. 77-206, August 1977.
: 3. "OSHA Safety and Health Standards, General Industry," (29CFR1910),
Occupational Safety and Health Administration, OSHA 2206 (Revised
January 1976).
.-. 4-. "Safety in Academic Chemistry Laboratories," American Chemical
Society Publication, Committee on Chemical Safety, 3rd Edition,
1979. •. •:
5. Munch, J. W., "Method 525.2-Determinatibn of Organic Compounds in
.- .:., Drinking Water by Liquid-Solid Extraction and Capillary Column
Chromatography/ Mass Spectrometry" in Methods for the Determination
of Organic Compounds in Drinking Water; Supplement 3 (1995).
USEPA,•National Exposure Research Laboratory, Cincinnati, Ohio
45268.
508.1-19
-------
17.0 TABLES, DIAGRAMS, FLOWCHARTS, AND VALIDATION DATA
TABLE 1. RETENTION TIMES FOR METHOD ANALYTES USING THE GC
COLUMN IN SECT. 6.7 AND THE GC CONDITIONS IN
SECT. 10.2
ANALYTE
Hexachlorocyclopentadiene
Etridiazole
Chloroneb
Propachlor
Trifluralin
HCH-alpha
Hexachl orobenzene
Simazine
Atrazine
HCH-Beta
HCH-Gamma
HCH-Delta
Chlorthalonil
Metribuzin
Heptachlor
Alachlor
Aldn'n
Metolachlor
Cyanazine
DC PA
Heptachlor Epoxide
Chlordane-Gamma
Endosulfan I :
Chlordane-alpha
Dieldrin
4,4'-DDE
RETENTION TIME (Min)
9.64
11.41
12.39
14.69
16.29
17.01
17.44
17.86
18.23
18.33
18.71
19.21
20.27
21.88
22.78
22.86
24.81
25.02
25.21
26.49
27.20
. 28.65
29.36
29.58
30.95
31.97
508.1-20
-------
TABLE 1. RETENTION TIMES FOR METHOD ANALYTES USING THE GC
COLUMN IN SECT. 6.7 AND THE GC CONDITIONS IN
SECT. 10.2
ANALYTE
Endrin
Butachlor3
Endosulfan II
Chlorbenzilate
4,4'-DDD
Endrin Aldehyde
Endo.sulfan suTfate
4,4'-DDT
Methoxychlor
cis-Permethrin
trans-Permethrin
Toxaphene3
Aroclor 1016a
Aroclor 1221a
Aroclor 1232a
Aroclor 1242a
Aroclor 1248a
Aroclor 1254a
Aroclor 1260a
Pentachlorointrobenzene (IS):
4,4-Dibromobiphenyl (SUR):
RETENTION TIME (Min)
32.24
32.65
32.81
32.98
33.49
33.96
35.43
35.80
39.38
44.98
45.42
33.53, 36.48, 39.12b
18.93, 22.55, 24.83b
13.67, 18.02, 19.93b
18.93, 22.55, 24.83b
18.93, 22.55, 24.83b
24.15, 24.83, 31.40b
31.80,, 34.12, 38.88b
35.65, 41.38, 43.08b
19.02 minutes
25.64 minutes
Retention time was determined with the following GC conditions:
Injector temperature -- 250°C
Detector temperature — 320°C
Injection volume — 2 #L, splitless for 45 sec.
Temperature program — Inject at 60°C and hold 1 min.
— program at 20°C/min. to 160°C hold 3 min.
— program at 3°C/min. to 275°C with no hold
-- program at 20°C/min. to 310°C with no hold
508.1-21
-------
TABLE 1. RETENTION TIMES FOR METHOD ANALYTES USING THE GC
COLUMN IN SECT. 6.7 AND THE GC CONDITIONS IN
SECT. 10.2
The IS retention time using these conditions is 21.15 min.
SUR retention time using these conditions is 28.18 min.
The
The retention times listed do not reflect the total number of
peaks characteristic of the multi-component analyte. Listed peaks
indicate those chosen for quantita'tion. Quantitative data is in
Table 3.
508.1-22
-------
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508.1-32
-------
Figure 1. Aroclor 1016. Chromatogram of LFB at 0.2 ug/L
20
25
TIME (MIN)
30
35
Figure 2. Aroclor 1221. Chromatogram of LFB at 0.2 ug/L
' — 1
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508.1-33
-------
Figure 3. Aroclor 1232. Chromatogram of LFB at 0.2ug/L
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Figure 4. Aroclor 1242. Chromatogram of LFB at 0.2ug/L
10
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20
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TIME(M1JN)
508.1-34
35
-------
Figures. Aroclor 1248. Chroma tog rani of LFB at 0.2ug/L
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20
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Figure 6. Aroclor 1254. Chromatogram of LFB at 0.2ug/L
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15
20
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TIME (MIN)
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508.1-35
-------
Figure 7. Aroclor 1260. Chromatogram of LFB at 0.2ug/L
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10
15
20
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TIME (MIN)
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40
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Figure 8. Toxaphene. Chromatogram of LFB at 0.2ug/L
• . I • i •
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15
20
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TIME (MIN)
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508.1-36
-------
METHOD 509. DETERMINATION OF ETHYLENE THIOUREA (ETU) IN
WATER USING GAS CHROMATOGRAPHY WITH A
NITROGEN-PHOSPHORUS DETECTOR
Revision 1.1
Edited by J. W. Munch (1995)
D.J. Munch (USEPA, Office of Water) and R.L. Graves (USEPA, NERL-Cincinnati)
T.M. Engel and S.T. Champagne, (Battelle, Columbus Division), National
Pesticide Survey Method 6, Revision 1.0, 1987
J.W. Eichelberger, Method 509 Revision 1.0 (1992)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
509-1
-------
METHOD 509
DETERMINATION OF ETHYLENE THIOUREA (ETU) IN WATER
USING GAS CHROMATOGRAPHY WITH A
NITROGEN-PHOSPHORUS DETECTOR
1. SCOPE AND APPLICATION
1.1 This method utilizes gas chromatqgraphy (GC) to determine ethylene
thiourea (ETU, Chemical Abstracts Registry No. 96-45-7) in water.
1.2 This method has been validated in a single laboratory during
development. The method detection limit (MDL) has been determined
in reagent water (1) and is listed in Table 2. Method detection
limits may vary among laboratories, depending upon the analytical
instrumentation used and the experience of the analyst. In addition
to the work .done during the development of this method and its use
in the National Pesticide Survey, an inter!aboratory method
validation study of this method has been conducted.
1.3 This method is restricted to use by or under the supervision of
analysts experienced in the use of GC and in the interpretation of
gas chromatograms. Each analyst must demonstrate the ability to
generate acceptable results with this method using the procedure
described in Sect. 9.3.
1.4 When a tentative identification of ETU is made using the recommended
primary GC column (Sect. 6.7.1), it must be confirmed by at least
one additional qualitative technique. This technique may be the use
of the confirmation GC column (Sect. 6.7.2) with the nitrogen-
phosphorus detector or analysis using a gas chromatograph/mass
spectrometer (GC/MS).
2. SUMMARY OF METHOD
2.1 The ionic strength and pH of a measured 50-mL aliquot of sample are
adjusted by addition of ammonium chloride and potassium fluoride.
The sample is poured onto a column of kieselguhr diatomaceous earth.
ETU is eluted from the column with 400 ml of methylene chloride. A
free radical scavenger is then added in excess to the eluate. The
methylene chloride eluant is concentrated to a volume of 5 ml after
solvent exchange with ethyl acetate. Gas chromatographic conditions
are described which permit the separation and measurement of ETU
with a nitrogen-phosphorus detector (NPD).
3. DEFINITIONS
3.1 ARTIFICIAL GROUND WATER — An aqueous matrix designed to mimic a
real ground water sample. The artificial ground water should be
reproducible for use by others.
509-2
-------
3.2 CALIBRATION STANDARD (CAL) — A solution prepared, from the primary
dilution standard solution or stock standard solutions and the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration.
3.3 METHOD DETECTION LIMIT (MDL) -- The minimum concentration of an
analyte that can be identified, measured, and reported with 99%
confidence that the analyte concentration is greater than zero.
3.4 INTERNAL STANDARD (IS) — A pure analyte(s) added to a sample,
extract, or standard solution in known amount(s) and used to measure
the relative responses of other method analytes and surrogates that
are components of the same sample or solution. The internal
standard must be an analyte that is not a sample component.
3.5 FIELD DUPLICATES (FD1 and FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as well as with
laboratory procedures.
3.6 INSTRUMENT PERFORMANCE CHECK SOLUTION (IPC) - A solution of one or
more method analytes, surrogates, internal standards, or other test
substances used to evaluate the performance of the instrument system
with respect to a defined set of criteria.
3.7 LABORATORY REAGENT BLANK (LRB) - An aliquot of reagent water or
other blank matrix that is treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents, internal
standards, and surrogates that are used with other samples. The LRB
is used to determine if method analytes or other interferences are
present in the laboratory environment, the reagents, or the
apparatus.
3.8 QUALITY CONTROL SAMPLE (QCS) -- A solution of method analytes of
known concentrations which is used to fortify an aliquot of LRB or
sample matrix. The QCS is obtained from a source external to the
laboratory and different from the source of calibration standards.
It is used to check laboratory performance with externally prepared
test materials.
3.9 STOCK STANDARD SOLUTION (SSS) — A concentrated solution containing
one or more method analytes prepared in the laboratory using assayed
reference materials or purchased from a reputable commercial source.
3.10 SURROGATE ANALYTE (SA) — A pure analyte(s), which is extremely
unlikely to be found in any sample, and which is added to a sample
aliquot in known amounts(s) before extraction or other processing
and is measured with the same procedures used to measure other
509-3
-------
sample components. The purpose of the SA is to monitor method
performance with each sample.
4. INTERFERENCES
4.1
4.2
4.3
4.4
4.5
Method interferences from contaminants in solvents, reagents,
glassware and other sample processing apparatus may cause discrete
artifacts or elevated baselines in gas chromatograms. All reagents
and apparatus must be routinely demonstrated to be free from
interferences under the conditions of the analysis by running
laboratory reagent blanks as described in Sect: 9.2.
4 1.1 Glassware must be scrupulously cleaned (2). Clean all glass-
ware as soon as possible after use by thoroughly rinsing with
the last solvent used in it. Follow by washing with hot
water and detergent and thorough rinsing with tap and reagent
water. Drain dry, and heat in an oven or muffle furnace at
400°C for 1 hr. Do not heat volumetric ware. Thermally
stable materials might not be eliminated by this treatment.
Thorough rinsing with acetone and methylene chloride may be
substituted for the heating. After drying and cooling, seal
and store glassware in a clean environment to prevent any
accumulation of dust or other contaminants. Store inverted
or capped with aluminum foil.
4.1.2 The use of high purity reagents and solvents helps to
minimize interference problems. Purification of solvents by
distillation in all-glass systems may be required.
Interfering contamination may occur when a sample containing a low
concentration of ETU is analyzed immediately following a sample
containing a relatively high concentration of ETU. Thorough
between-sample rinsing of the sample syringe and associated
equipment with ethyl acetate can minimize sample cross contamin-
ation. After analysis of a sample containing high concentrations of
ETU, one or more injections of ethyl acetate should be made to
ensure that accurate values are obtained for the next sample.
Matrix interferences may be caused by contaminants that are
coextracted from the sample. The extent of matrix interferences may
vary considerably from source to source, depending upon the sample.
Tentative identifications must be confirmed using the confirmation
column (Sect. 6.7.2) and the conditions in Table 1.
Studies have shown that persistent ETU decomposition is
circumstantially linked to free radical mechanism. Addition of a
free radical scavenger is necessary to prohibit any free radical
reactions.
It is important that samples and working standards be contained in
the same solvent. The solvent for working standards must be the
same as the final solvent used in sample preparation. If this is
509-4
-------
not the case, chromatographic comparability of standards to sample
may be affected. >
5. SAFETY
5.1 ETU is a suspected carcinogen and teratogen. Primary standards of
ETU should be prepared in a hood. A NIOSH/MESA approved toxic gas
respirator should be worn when the analyst handles high concentra-
tions of ETU. Each laboratory is responsible for maintaining a
current awareness file of OSHA regulations regarding the safe
handling of the chemicals specified in this method. A reference
file of material data handling sheets should also be made available
to all personnel involved in the chemical analysis. Additional
references to laboratory safety are available and have been
identified (3-5) for the information of the analyst.
6. EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.)
6.1 SAMPLING CONTAINERS — 60-mL screw cap vials equipped with Teflon-
faced silicone septa. Prior to use, wash vials and septa with
detergent and'rinse with tap and distilled water. Allow the septa
to air dry at room temperature, place in a 105°C oven for 1 hr, then
remove and allow to cool in an area known to be free of organics.
Heat vials at 400°C for 1 hr to remove organics.
6.2 GLASSWARE
6.2.1 Concentrator tube, Kuderna-Danish (K-D) - 10-mL or 25-mL,
graduated. Calibration must be checked at the volumes
employed in the test. Ground glass stoppers are used to
prevent evaporation of extracts.
6.2.2 Evaporative flask, K-D - 500-mL Attach to concentrator tube
with springs.
6.2.3 Snyder column, K-D - three-ball macro to which a condenser
can be connected to collect solvent.
6.2.4 Vials - Glass, 5 to,10-mL capacity with Teflon lined screw
caps.
6.3 Boiling stones - carborundum, #12 granules, heat at 400°C for 30 min
prior to use. Cool and store in a desiccator.
6.4 Water bath - Heated, capable of temperature control (±2°C). The
bath should be used in a hood.
6.5 Balance - Analytical, capable of accurately weighing to the nearest
0.0001 g.
509-5
-------
6.6 Tube heater - Capable of holding 8 K-D concentrator tubes and
heating the mid-section of the tubes to 35-40°C while applying a
nitrogen stream. '
6.7 GAS CHROMATOGRAPH - Analytical system complete with GC equipped with
a nitrogen-phosphorus detector, split/splitless injector for
capillary columns and all required accessories. A data system is
recommended for measuring peak areas. An autoinjector is recommended
to improve precision of analyses.
6.7.1 Primary column - DB-Wax or equivalent,10 m x 0.25 mm I.D.
bonded fused silica column, 0.25 urn film thickness.
Validation data presented in this method were obtained using
this column. Alternative columns may be used provided equal
or better peak separation and peak shape are obtained.
6.7.2 Confirmation column - DB-1701 or equivalent, 5 m x 0.25 mm
I.D. bonded fused silica column, 0.25 urn film thickness.
6.7.3 Detector - Nitrogen-phosphorus (NPD). This detector has
proven effective in the analysis of ETU in fortified reagent
and artificial ground waters.
7. REAGENTS AND STANDARDS
7.1 REAGENT WATER — Reagent water is defined as water in which an
interference is not observed at the retention time for ETU at the
method detection limit. A Millipore Super-Q Water System or its
equivalent may be used to generate reagent water. Water that has
been charcoal filtered may also be suitable.
7.2 Methylene chloride, ethyl acetate — distilled-in-glass quality or
equivalent.
7.3 Nitrogen gas - high purity.
7.4 Extrelut QE Extraction column - Obtained from EM Science (Catalog
No. 902050-1) or equivalent. Extrelut QE columns contain a
specially modified form of large pore Kieselguhr with a granular
structure.
7.5 Ammonium chloride, granular, ACS grade — for pH and ionic strength
adjustment of samples.
7.6 Potassium fluoride, anhydrous, ACS grade — for ionic strength
adjustment of sample.
7.7 Dithiothreitol (DTT) (Cleland's reagent) - for use as a free-radical
scavenger (available from Aldrich Chemical Co.).
7.7.1 DTT in ethyl acetate, 1000 /ig/ml_ - May be prepared by adding
1 g DTT to a 1-L volumetric flask and diluting to volume with
509-6
-------
ethyl Acetate. Smaller amounts may be prepared if only a
small number of samples are to be analyzed. Store at room
temperature.
7.8 Propylene thiourea (PTU) - For use as a surrogate standard.
Prepared from carbon disulfide and 1,2-diaminopropane using the
procedure published by Hardtmann, et. al. (Journal of Medicinal
. , Chemistry, 18(5), 447-453, 1975), or purchase from commercial
sources.
7.9 3,4,5,6-Tetrahydro-2-pyrimidinethiol (THP) - >98% purity, for use as
an internal standard (available from Aldrich Chemical Co.).
7.10 STOCK STANDARD SOLUTION (0.10 fig/pi) - The stock standard solution
may be purchased as a certified solution or prepared from pure
standard material using the following procedure:
7.10.1 Prepare stock standard solution by accurately weighing
0.0010 g of pure ETU. Dissolve the ETU in ethyl acetate
containing 1000 /ig/mL of DTT and dilute to volume in a 10-mL •
volumetric .flask. Larger volumes may.be used at the
convenience of the analyst. If ETU purity is certified at
96% or greater, the weight may be used without correction to
calculate the concentration of the stock standard.
Commercially prepared stock standards may be used at any
concentration if they are certified by the manufacturer or by
an independent source.
7.10.2 Transfer the stock standard solution into a Teflon sealed
screw cap vial. Store at room temperature and protect from
light.
7.10.3 The stock standard solution should be replaced after two
weeks or sooner if comparison with laboratory control
standards indicates a problem.
7.11 INTERNAL STANDARD FORTIFYING SOLUTION — Prepare an internal
standard fortifying solution by accurately weighing 0.0010 g of pure
THP. Dissolve the THP in ethyl acetate containing 1000 /ig/mL of DTT
and dilute to volume in a 10-mL volumetric flask. Transfer the
solution to a Teflon sealed screw cap bottle and store at room
temperature. Addition of 50 nl of the internal standard fortifying
solution to 5 mL of sample extract results in a final internal
standard concentration of 1.0 /zg/mL.
7.12 SURROGATE STANDARD FORTIFYING SOLUTION - Prepare a surrogate
standard fortifying solution by accurately weighing 0.0010 g of pure
PTU. Dissolve the PTU in ethyl acetate containing 1000 fig/ml of DTT
and dilute to volume in a 10-mL volumetric flask. Transfer the
solution to a Teflon sealed screw cap bottle and store at room
temperature. Addition of 5 /zL of the surrogate standard fortifying
solution to a sample prior to extraction results in a surrogate
509-7
-------
I
standard concentration in the sample of 10 /ig/L and, assuming
quantitative recovery of PTU, a surrogate standard concentration in
the final extract of 0.10 /zg/mL.
7.13 INSTRUMENT PERFORMANCE CHECK SOLUTION - Prepare the instrument
performance check solution by adding 10 pi of the ETU stock standard
solution, 1.0 mL of the internal standard fortifying solution, and
100 nL of the surrogate standard fortifying solution to a 100-mL
volumetric flask and diluting to volume with ethyl acetate
containing 1000 /jg/mL of DTT. Transfer the solution to a Teflon
sealed screw cap bottle and store at room temperature.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 SAMPLE COLLECTION — Grab samples must be collected in 60-mL glass
containers fitted with Teflon-liiied screw caps (Sect. 6.1). Conven-
tional sampling practices (6) should be followed; however, the
bottle must not be prerinsed with sample before collection.
8.2 SAMPLE STORAGE — The samples must be iced or refrigerated at 4°C
and protected from light from the time of collection until
extraction. Samples should be extracted as soon as possible after
collection to avoid possible degradation of ETU. All samples must
be extracted within 14 days of collection. Extracts must be stored
under refrigeration and protected from light. Extracts must be
analyzed within 28 days of extraction.
8.3 SAMPLE PRESERVATION — ETU may chemically degrade in some samples
even when the sample is refrigerated. When this method was
developed, mercuric chloride was used to ensure against biological
degradation. No suitable preservation reagent has been found other
than mercuric chloride. However, the use of mercuric chloride is
not recommended due to its toxicity and potential harm to the
environment. Biological degradation may occur only rarely in
samples with limited biological activity such as finished drinking
waters.
9. QUALITY CONTROL
9.1 Each laboratory using this method is required to operate a formal
quality control (QC) program. The minimum requirements of this
program consist of the following; an initial demonstration of
laboratory capability; measurement of the surrogate compound in
each sample; analysis of laboratory reagent blanks, laboratory
fortified blanks, laboratory fortified matrix samples, and QC check
standards. A MDL for ETU must also be determined.
I '
9.2 LABORATORY REAGENT BLANKS — Before processing any samples, the
analyst must demonstrate that all glassware and reagent
interferences are Bunder control. This is accomplished by analyzing
a laboratory reagent blank (LRB). A LRB is a 50-mL aliquot of
reagent water, fortified with the internal standard and the
509-8
-------
surrogate compound, that is analyzed according to Sect. 11 exactly
as if it were a sample. Each time a set of samples is analyzed or
reagents are changed, it must be demonstrated that the laboratory
reagent blank is free of contamination that would prevent the
determination of ETU at the MDL. All interfering contaminants must
be eliminated before sample analyses are started.
9.3 Initial Demonstration of Capability.
9.3.1 Select a representative fortified concentration (about 10
times MDL or at a concentration in the middle of the
calibration range established in Section 10) for ETU.
Prepare a 4-7 replicate LFBs containing ETU at the selected
concentration, and analyze each LFB according to procedures
beginning in Sect. 11.
9.3.2 The mean recovery value for these samples must fall in the
range of ± 20% of the fortified amount. The precision of
these measurements, expressed as RSD, must be 20% or less.
If the data meet these criteria, performance is considered
acceptable. If acceptance criteria is not met, this
procedure must be repeated using fresh replicate samples
until satisfactory performance has been demonstrated.
9.3.3 To determine the MDL, prepare a minimum of 7 LFBs at a low
concentration. The fortification concentration in Table 2
may be used as a guide, or use calibration data obtained in
Section 10 to estimate a concentration that will produce a
peak with a 3-5 times signal to noise response. Extract and
analyze each replicate according to Sections 11 and 12. It
is recommended that these LFBs be prepared and analyzed over
a period of several days, so that day to day variations are
reflected in the precision of the measurements. Calculate
mean recovery and standard deviation for each analyte. Use
the standard deviation and the equation given in Section 13
to calculate the MDL.
9.3.4 The initial demonstration of capability is used primarily to
preclude a laboratory from analyzing unknown samples via a
new, unfamiliar method prior to obtaining some experience
with it. It is expected that as laboratory personnel gain
experience with this method the quality of data will improve
beyond those required here.
9.4 The analyst is permitted to modify GC columns or GC conditions to
improve the separations, identifications, or lower the cost of
measurement. Each time a modification is made, the analyst is
required to repeat the procedure in Sect. 9.3.
509-9
-------
9.5 ASSESSING SURROGATE RECOVERY
9.5.1 All samples and blanks must be fortified with the surrogate
compound according to Sect. 11.1 before extraction to monitor
preparation and analysis of samples.
9.5.2 Surrogate recovery must be evaluated for acceptance by
determining whether the measured surrogate concentration
(expressed as percent recovery) falls within the required
recovery limits. Performance-based recovery criteria for PTU
has been generated from single-laboratory results. Measured
recovery of PTU must be between 70 and 130 percent.
9.5.3 If the surrogate recovery for? a sample or blank is outside of
the required surrogate recovery limits specified in Sect.
9.5.2, the laboratory must take the following actions:
(1) Check calculations to make sure there are no errors.
(2) Check internal standard and surrogate standard
solutions for degradation, contamination, or other
obvious abnormalities.
(3) Check instrument performance.
•
Reinject the extract if the above steps fail to
reveal the cause of the problem. The problem must
be identified and corrected before continuing.
Reanalyzing the sample or blank, if possible, may be
the only way to'solve the problem.
9.6 ASSESSING THE INTERNAL STANDARD
9.6.1 The analyst is must monitor the internal standard peak area
in all samples and blanks during each analysis day. The IS
response for any sample chromatogram should not deviate from
the IS response of the most recent daily calibration check
standard by more than 20%.
9.6.2 If >20% deviation occurs with an individual extract, optimize
instrument performance and inject a second aliquot of that
extract. If the reinjected aliquot produces an acceptable IS
response, report results for that injection. If a deviation
>30% is obtained for the reinjected extract, reanalyze the
sample beginning with Sect. 11, provided the sample is still
available. Otherwise, report results obtained from the
reinjected extract, but mark them as suspect.
9.6.3 If consecutive samples fail the IS response acceptance
criteria, immediately analyze a medium calibration check
standard. If the check standard provides a response for the
IS within 20% of the predicted value, then follow procedures
509-10
-------
. itemized in Sect. 9.6.2 for each sample failing the IS
response criteria. If the check standard provides a response
which deviates more than 20% from the predicted value, then
.the analyst must recalibrate.
9.7 ASSESSING LABORATORY PERFORMANCE
9.7.1 The laboratory must analyze at least one laboratory fortified
blank (LFB) per sample set. The ETU fortifying concentration
in the LFB should be 10 times the MDL or at a concentration
near the middle of the calibration range demonstrated by the
laboratory. Calculate the percent recovery of the ETU. If
the recovery falls outside the control limits (see Sect.
9.7.2), the system is judged out of control and the source of
the problem must be identified and resolved before continuing
analyses.
9.7.2 Until sufficient LFB data become available, usually a minimum
of 20 to 30 results, the laboratory should assess its
performance against the control limits described in Sect.
9.3.2. When sufficient laboratory performance data become
available, develop control limits from the mean percent
recovery (R) and standard deviation (S) of the percent
recovery. These data are used to establish upper and lower
control limits as follows:
Upper Control Limit = R + 3S
Lower Control Limit = R - 3S
After five to ten new recovery measurements are made, control
limits should be recalculated using only the most recent 20
to 30 data points. Control limits must not exceed the fixed
acceptance limits in Section 9.3.2.
9.8 Assessing Analyte Recovery - Laboratory Fortified Sample Matrix
9.8.1 The laboratory must add a known concentration to a minimum of
5% of the routine samples or one sample per set, whichever is
greater. The fortified concentration should not be less than
the background concentration of the sample selected for
fortification. Ideally, the concentration should be the same
as that used for the laboratory fortified blank (Sect.
9.3.1). Over time, samples from all routine sample sources
should be fortified.
9.8.2 Calculate the percent recovery, P of the concentration for
each analyte, after correcting the analytical result, X, from
the fortified sample for the background concentration, b,
measured in the unfortified sample, i.e.,:
P = 100 (X - b) / fortifying concentration,
509-11
-------
and compare these values recoveries listed in Table 2. The
calculated value of P must fall in the range of ± 25% of the
amount fortified. If P exceeds this control limit the
results for that analyte in the unfortified matrix must be
listed as suspect due to matrix interference.
9.9 ASSESSING INSTRUMENT PERFORMANCE — Instrument performance should be
monitored on a daily basis by analyzing the instrument performance
check solution (IPC). The IPC solution contains compounds monitor
instrument sensitivity and column performance. The IPC components
and performance criteria are listed in Table 4. Inability to
demonstrate acceptable instrument performance indicates the need for
remedial action on the GC-NPD system. A chromatogram from the
analysis of the IPC is shown in Figure 1. The sensitivity
requirements are set according the MDL. MDLs will vary somewhat in
different laboratories according to instrument capabilities. The
laboratory should adjust the amount of ETU in the IPC based on the
demonstrated sensitivity of the instrumentation used.
9.10 QC Samples- It is recommended that the laboratory periodically (at ,
least quarterly), analyze one or more standard materials from an
outside source to validate performance.
9.11 ADDITIONAL QC — It is recommended that the laboratory adopt
additional quality assurance practices for use with this method.
The specific practices that are most productive depend upon the
needs of the laboratory and the nature of the samples.
10. CALIBRATION AND STANDARDIZATION
10.1 Establish GC operating parameters equivalent to those indicated in
Table 1. Ensure that the gas chromatographic system is working
properly by injecting the instrument performance check solution
(Sect. 7.14) and checking for proper peak shapes, reasonable
retention times, and sufficient sensitivity. The GC system is
calibrated using the internal standard technique (Sect. 10.2).
10.2 INTERNAL STANDARD CALIBRATION PROCEDURE — This approach requires
the analyst to use at least one internal standard compatible in
analytical behavior to the compound of interest. The analyst must
further demonstrate that the measurement of the internal standard is
not affected by method or matrix interferences. In developing this
method, THP (3,4,5,6-tetrahydro-2-|)yrimidinethiol) was found to be a
, suitable internal standard.
10.2.1 Prepare ETU calibration standards at five concentration
levels by adding volumes of the ETU stock standard solution
to five volumetric flasks. To each flask, add a known
constant amount of internal standard and dilute to volume
with ethyl acetate containing 1000 /jg/mL of DTT. One of the
standards should be representative of an ETU concentration
near, but above, the MDL. The other concentrations should
509-12
-------
correspond to the range of concentrations expected in the
sample concentrates, or should define the working range of
the detector.
10.2.2 Inject each calibration standard and tabulate the relative
response for ETU to the internal standard (RRa) using the
equation:
RR = A/A,
is
where: Aa = the peak area of ETU, and
Ajs = the peak area of the internal standard.
Generate a calibration curve of RR versus ETU
concentration in the sample in
10.2.3 The working calibration curve must be verified on each
working day by the measurement of a minimum of two
calibration check standards, one at the beginning and one at
the end of the analysis day. These check standards should be
at two different concentration levels to verify the .
calibration curve. For extended periods of analysis (greater
than 8 hrs.), it is strongly recommended that check standards
be interspersed with samples at regular intervals during the
course of the analyses. If the ETU response varies from the
predicted response by more than 20%, the test should be
repeated using a fresh calibration standard. Alternatively, ,
a new ETU calibration curve should be prepared. Any sample
extracts analyzed since the last acceptable calibration check
should be considered suspect, and should be reanalyzed after
calibration is restored. •
11. PROCEDURE
11.1 SAMPLE EXTRACTION
11.1.1 Pipet a 50-mL aliquot of water sample into a sample bottle
(Sect. 6.1) containing 1.5 g of ammonium chloride and 25 g of
potassium fluoride. Seal the bottle and shake vigorously
until salts are dissolved. Fortify the sample with 5 /il_ of
the surrogate standard fortifying solution (Sect. 7.13).
11.1.2 Pour contents of the bottle onto the Extrelut (sorbent)
column (Sect. 7.4). Allow the column to stand undisturbed
for 15 min.
11.1.3 Add 5 ml of 1000 /ig/mL DTT in ethyl acetate to a K-D
concentrator tube equipped with a 500-mL flask.
11.1.4 Add 400 ml of methylene chloride in 50-75 ml portions to the
Extrelut column and collect the eluant in the K-D apparatus
(Sect. 11.1.3).
509-13
-------
11.2 EXTRACT CONCENTRATION
11.2.1 Conduct the following work in a fume hood which is properly
vented. Add 1 or 2 boiling stones to the K-D apparatus and
attach a macro Snyder column. Prewet the Snyder column by
adding about 1 mL of met.hylene chloride to the top. Attach a
condenser to the Snyder column to recover the methylene
chloride as it escapes the column. Place the K-D apparatus in
a 65-70°C water bath so that the K-D tube is partially
immersed in the hot water, and the entire lower rounded
surface of the flask is bathed with hot vapor. When the
apparent volume of liquid reaches 5 ml, remove the K-D
apparatus and allow it to drain and cool for at least 10 min.
11.2.2 Reduce the liquid volume in the K-D tube to approximately 1
ml by placing the sample in a tube heater at 35-40°C under a
stream of nitrogen. The tube heater heats the solvent in the
K-D tube at volume markings between 1 and 10 ml.
11.2.3 Dilute sample to 5 ml with ethyl acetate; rinse walls of K-D
tube while adding ethyl acetate. Immediately fortify the
sample with 50 ^L of internal standard fortifying solution
(Sect. 7.12). Agitate sample to disperse internal standard.
Transfer sample to a GC vial and determine ETU by GC-NPD as
described in Sect. 11.3.
11.3 GAS CHROMATOGRAPHY
11.3.1 Table 1 summarizes the recbmmended GC operating conditions.
Included in Table 1 are retention times observed using this
method. An example of the separations achieved using these
conditions are shown in Figure 1. Other GC columns or
chromatographic conditions may be used if the requirements of
Sect. 9.3 are met.
11.3.2 Calibrate or verify the system calibration daily as described
in Sect. 10. The standards and extracts must be in ethyl
acetate.
11.3.3 Inject 2 /iL of the sample extract. Record the resulting peak
size in area units.
11.3.4 The width of the retention time window used to make
identifications should be based upon measurements of actual
retention time variations of standards over the course of a
day. Three times the standard deviation of a retention time
can be used to calculate a suggested window size for a
compound. However, the experience of the analyst should
weigh heavily in the interpretation of chromatograms.
11.3.5 Confirmatory techniques such as chromatography with a
dissimilar column, or an alternate technique such as particle
509-14
-------
beam/HPLC/mass spectrometry (EPA Method 553) may be used for
confirmation of ETU in extracts prepared by this method. A
suggested confirmation column is described in Table 1.
12. DATA ANALYSIS AND CALCULATIONS
12.1 Calculate the ETU concentration in the sample from the ETU relative
response (RRa) to the internal standard using the multi-point
calibration curve described in Sect. 10.2.2. Do not use the daily
calibration verification standard to quantitate ETU in samples. Do
not extrapolate beyond the linear range established during
calibration.
13. METHOD PERFORMANCE
13.1 .In a single 'laboratory, ETU recovery and precision data from reagent
water were determined at four concentration levels. Results were
used to determine the MDL and demonstrate method range. These data
are given in Table 2. The equation used to calculate the MDL are as
follows:
MDL S t(lv1|1_alpha = 0_99)
where:
-- = o.99i = Student's t value for the 99%
confidence level with n-1 degrees of freedom
n = number of replicates
'..';' S = standard deviation of replicate analyses.
13.2 In a single laboratory, ETU recovery and precision data from two
artificial ground waters were determined at a single concentration
level of 10 /jg/L. Results were used to demonstrate applicability of
the method to different ground water matrices. These data are
listed in Table 3.
,14. POLLUTION PREVENTION
14.1 Although this method requires 400 mL methylene chloride extracting
solvent per sample, no pollution of the environment will occur due
to the recovery of the solvent during the extract concentration
procedure. Very little solvent will escape the fume hood. No other
solvents are utilized in this method except for the very small
amount of ethyl acetate needed to make up calibration and
fortification standards. These small amounts of solvent pose no
threat to the environment..-.
14.2 For information about pollution prevention that may be applicable to
laboratory operations, consult "Less is Better: Laboratory Chemical
509-15
-------
Management for Waste Reduction" available from the American Chemical
Society's Department of Government Relations and Science Policy,
1155 16th Street N.W., Washington, D.C. 20036.
15. WASTE MANAGEMENT
15.1 It is the laboratory's responsibility to comply with all federal,
state, and local regulations governing waste management,
particularly the hazardous waste identification rules, and land
disposal restrictions. The laboratory has the responsibility to
protect the air, water, and land by minimizing and controlling all
releases from fume hoods and bench operations. Compliance is also
required with any sewage discharge permits and regulations. For
further information on waste management, consult "The Waste
Management Manual for Laboratory Personnel," also available from the
American Chemical Society at the address in Sect. 14.2.
16. REFERENCES
1. 40 CFR, Part 136, Appendix B
2. ASTM Annual Book of Standards, Pa,rt 31, D3694, "Standard Practice
for Preparation of Sample Containers and for Preservation," American
Society for Testing and Materials, Philadelphia, PA, p. 679, 1980.
3. "Carcinogens - Working with Carcinogens," Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77-206, Aug. 1977,
4. "OSHA Safety and Health Standards, General Industry," (29 CFR 1910),
Occupational Safety and Health Administration, OSHA 2206, (Revised,
January 1976).
5. "Safety in Academic Chemistry Laboratories," American Chemical
Society Publication, Committee on Chemical Safety, 3rd Edition,
1979.
6. ASTM Annual Book of Standards, Part 31, D3370, "Standard Practice
for Sampling Water," American Society for Testing and Materials,
Philadelphia, PA, p. 76, 1980.
509-16
-------
17. TABLES. DIAGRAMS. FLOWCHARTS. AND VALIDATION DATA
TABLE 1. PRIMARY AND CONFIRMATION CHROMATOGRAPHIC CONDITIONS
Analyte
Retention Time, min
Primary column
Confirmation column
ETU
THP (internal standard)
PTU (surrogate standard)
3.5
5.1
2.7
4.5
5.0
2.2
Primary conditions:
Column:
Carrier gas:
Makeup gas:
Detector gases:
Injector temperature:
Detector temperature:
Oven temperature:
Sample:
Detector:
Confirmation conditions:
Column:
Carrier gas:
Makeup gas:
Detector gases:
Injector temperature:
Detector temperature:
Oven temperature:
Sample:
Detector:
10 m long x 0.25 mm I.D. DB-Wax bonded fused
silica column (J&W), 0.25 m film thickness
He @ 30 cm/sec linear velocity
He @ 30 mL/min flow
Air @ 100 mL/min flow; H2 @ 3 mL/min flow
220°C
230°C
220'°C isothermal
2 ill splitless; 9 sec split delay
Nitrogen-phosphorus
5 m long x 0.25 mm I.D. DB-1701 bonded fused
silica column (J&W), 0.25 m film thickness
He @ 30 cm/sec linear velocity
He @ 30 mL/min flow
Air G> 100 m:/min flow; H2 @ 3 mL/min flow
150°C
270°C
150°C isothermal
2 (J.L splitless; 9 sec split delay
Nitrogen-phosphorus
509-17
-------
TABLE 2. RESULTS FROM MDL AND METHOD RANGE STUDIES (a)
Fortified
Level ,
5.0
10
25
100
Amt in
Blank,
0.492
ND (b)
ND
ND
n(d)
7
7
7
7
.. • - . ! - '
R(e)
97 (c)
102
94
97
S(f)
0.845
0.886
1.31
5.96
RSD(g)
17
9
6
6
MDL
2.7
-
(a) Studies conducted in reagent water; average recovery of PTU surrogate
from seven fortified reagent water samples was 100% (RSD) was 8.5/«.
(b) ND = not detected.
(c) Data corrected for amount detected in blank.
(d) n = number of recovery data points.
(e) R ~ aveVage percent recovery.
(f) S = standard deviation.
(g) RSD = percent relative standard deviation.
509-18
-------
TABLE 3. RESULTS FROM MATRIX EVALUATION STUDIES (a)
Matrix
Hard (b)
Organic-contaminated (c)
(a) Samples were fortified
Amt. in
Blank,
M9/L
ND (d)
ND
at 10 fj.g/1 level
(b) Absopure Natural Artesian Spring water
n(e) R(f) .
7 93
7 93
with ETU.
obtained from th
S(g) RSD(h)
0.372 4
0.253 3
IB Absooure Water
Company in Plymouth, Michigan.
(c) Reagent water fortified with fulvic acid at the 1 mg/L concentration
level. A well-characterized fulvic acid, available from the
International Humic Substances Society (associated with the United
States Geological Survey in Denver, Colorado), was used.
(d) ND = not detected.
(e) n = number of recovery data points.
(f) R = average percent recovery.
(g) S = standard deviation.
(h) RSD = percent relative standard deviation.
509-19
-------
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509-21
-------
THIS PAGE LEFT BLANK INTENTIONALLY
509-22
-------
METHOD 515.1. DETERMINATION OF CHLORINATED ACIDS IN WATER BY GAS
CHROMATOGRAPHY WITH AN ELECTRON CAPTURE DETECTOR
Revision 4.1
Edited by J.W. Munch (1995)
R.C. Dressman and J.J. Lichtenberg - EPA 600/4-81-053, Revision 1.0 (1981)
J.W. Hodgeson - Method 515, Revision 2.0 (1986)
D. J. Munch (USEPA, Office of Water) and T. Engel (Battelle Columbus
Laboratories) - National Pesticide Survey Method 3, Revision 3 0
(1987)
R.L. Graves - Method 515.1, Revision 4.0 (1989)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
515.1-1
-------
METHOD 515.1
DETERMINATION OF CHLORINATED ACIDS IN WATER BY GAS
CHROMATOGRAPHY WITH AN ELECTRON CAPTURE DETECTOR
1. SCOPE AND APPLICATION
1.1
1.2
1.3
This is a gas chromatographic (GC) method applicable to the
determination of certain chlorinated acids in ground water and
finished drinking water. The following compounds can be determined
by this method:
Analvte
Acifluorfen*
Bentazon
Chloramben*
2,4-D
Dalapon*
2,4-DB
DCPA acid metabolites(a)
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydi camba
4-Nitrophenol*
Pentachlorophenol (PCP)
Picloram
2,4,5-T
2,4,5-TP
Chemical Abstract Services
Registry Number
50594-66-6
25057-89-0
133-90-4
94-75-7
75-99-0
94-82-6
1918-
51-
120-
88-
7600
100
87
1918
93
93
-00-9
•36-5
-36-5
-85-7
-50-2
-02-7
-86-5
-02-1
-76-5
-72-1
(a)DCPA monoacid and diacid metabolites included in method scope;
DCPA diacid metabolite used for validation studies.
*These compounds are only qualitatively identified. These compounds
are not quantitated because control over precision has not been
accomplished.
This method is also applicable to the determination of salts and
esters of analyte acids. The form of each acid is not distinguished
by this method. Results are calculated and reported for each listed
analyte as the total free acid.
This method has been validated ijfi-a single laboratory and estimated
detection limits (EDLs) and method detection limits (MDLs) have been
determined for the analytes above (Sect.13). Observed detection
limits may vary between ground waters, depending upon the nature of
interferences in the sample matrix and the specific instrumentation
used.
515.1-2
-------
1.4 This method is restricted to use by or under the supervision of
analysts experienced in the use of GC and in the interpretation of
gas chromatograms. Each analyst must demonstrate the ability to
the
1.5
Analytes that are not separated chromatographically i.e., which have
very similar retention times, cannot be individually identified and
measured in the same calibration mixture or water sample unless an
alternate technique for identification and quantitation exist (Sect.
•I J. • -7 ) •
1.6 When this method is used to analyze unfamiliar samples for any or
all of the analytes above, analyte identifications must be confirmed
by at least one additional qualitative technique.
2. SUMMARY OF METHOD
2.1 A measured-volume of sample of approximately li is adjusted to PH
12 with 6 N sodium hydroxide and shaken for 1 hr to hydrolyze
derivatives. ( Note: Since many of the herbicides contained in this
method are applied as a variety of esters and salts, it is vital to
hydrolyze them to the parent acid prior to extraction.) Extraneous
organic material is removed by a solvent wash. The sample is acidi-
fied, and the chlorinated acids are extracted with ethyl ether by
shaking in a separatory funnel or mechanical tumbling in a bottle
The acids are converted to their methyl esters using diazomethane'as
'
™nc , trimethylsilyldiazomethane
(IMSD). Excess denvatizing reagent is removed, and the esters are
determined by capillary column/GC using an electron capture detector
(hLL) ) .
i
2.2 The method provides aa optional Florisil separation procedure to aid
in the elimination of interferences that may be encountered.
3. DEFINITIONS
3.1 INTERNAL STANDARD - A pure analyte(s) added to a solution in known
amount (s) and used to measure the relative responses of other method
analytes and surrogates that are components of the same solution
The internal standard must be an analyte that is not a sample
component. K
3.2 SURROGATE ANALYTE - A pure analyte(s), which is extremely unlikely
to be found in any sample, and which is added to a sample aliquot in
known amount (s) before extraction and is measured with the same
procedures used to measure other sample /components. The purpose of
a surrogate analyte is to monitor method performance with each
sample.
3.3 LABORATORY DUPLICATES (LD1 and LD2) - Two sample aliquots taken in
the analytical laboratory and analyzed separately with identical
procedures. Analyses of LD1 and LD2 give a measure of the precision
515.1-3
-------
associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures.
3.4 FIELD DUPLICATES (FD1 and FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as weTl as with
laboratory procedures.
3.5 LABORATORY REAGENT BLANK (LRB) — An aliquot of reagent water that
is treated exactly as a sample including exposure to all glassware,
equipment, solvents, reagents, internal standards, and surrogates
that are used with other samples. The LRB is used to determine if
method analytes or other interferences are present in the laboratory
environment, the reagents, or the apparatus. ,
3.6 FIELD REAGENT BLANK (FRB) — Reagent water placed in a sample
container in the laboratory and treated as a sample in all respects,
including exposure to sampling site conditions, storage,
preservation and all analytical procedures. The purpose of the FRB
is to determine if method analytes or other interferences are
present in the field environment.
3.7 LABORATORY PERFORMANCE CHECK SOLUTION (LPC) — A solution of method
analytes, surrogate compounds, and internal standards used to
evaluate the performance of the instrument system with respect to a
defined set of method criteria. |
3.8 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water to
which known quantities of the method analytes are added in the
laboratory. The LFB is analyzed exactly like a sample, and its
purpose is to determine whether the methodology is in control, and
whether the laboratory is capable of making accurate and precise
measurements at the required method detection limit.
3.9 LABORATORY FORTIFIED SAMPLE MATRIX (jLFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added'in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
3.10 STOCK STANDARD SOLUTION — A concentrated solution containing a
single certified standard that is a method analyte, or a
concentrated solution of a single analyte prepared in the laboratory
with an assayed reference compound. Stock standard solutions are
used to prepare primary dilution standards.
3.11 PRIMARY DILUTION STANDARD SOLUTION — A solution' of several analytes
prepared in the laboratory from stock standard solutions and diluted
515.1-4
-------
solutions/0 ^^^ Ca1ibration S°lut1ons and other needed analyte
3.12 CALIBRATION STANDARD (CAL) - A solution prepared from the primary
dilution standard solution and stock standard solutions of the
McIlTJ standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analvte
concentration. a.ia.jrLe
3.13 QUALITY CONTROL SAMPLE (QCS) -- A sample matrix containing method
analytes or a solution of method analytes in a water miscible
solvent which is used to fortify reagent water or environmental
samples. The QCS is obtained from a source external to the
laboratory, and is used to check laboratory performance with
externally prepared test materials.
4. INTERFERENCES
4.1 Method interferences may be caused by contaminants in solvents
reagents glassware and other sample processing apparatus that'lead
to discrete artifacts or elevated baselines in gas chromatograms.
All reagents and apparatus must be routinely demonstrated to be free
from interferences under the conditions of the analysis by running
laboratory reagent blanks as described in Sect. 9.2.
4.1.1 Glassware must be scrupulously cleaned.(1) Clean all glass-
. ware as soon as possible after use by thoroughly rinsing with
the last solvent used in it. Follow by washing with hot
water and detergent and thorough rinsing with dilute acid
tap and reagent water. Drain dry, and heat in an oven or'
muffle furnace at 400°C for 1 hr. Do not heat volumetric
glassware. Thermally stable materials such as PCBs might not
be eliminated by this treatment. Thorough rinsing with
acetone may be substituted for the heating. After drying and
cooling, seal and store glassware in a clean environment to
prevent any accumulation of dust or other contaminants
Store inverted or capped with aluminum foil.
4.1.2 The use of high purity reagents and solvents helps to
minimize interference problems. Purification of solvents by
distillation in all-glass systems may be required
WARNING: When a solvent is purified, stabilizers added by
the manufacturer are removed, thus potentially making the
solvent hazardous. Also, when a solvent is purified
preservatives added by the manufacturer are removed 'thus
potentially reducing the shelf-life. '
4.2 The acid forms of the analytes are strong organic acids which react
readily with alkaline substances and can be lost during sample
preparation. Glassware and glass wool must be acid-rinsed with IN
hydrochloric acid and the sodium sulfate must be acidified with
sulfuric acid prior to use to avoid analyte losses due to
adsorption.
515.1-5
-------
4.3 Organic acids and phenols, especially chlorinated compounds, cause
the most direct interference with the determination. Alkaline
hydrolysis and subsequent extraction of the basic sample removes
many chlorinated hydrocarbons and phthalate esters that might
otherwise interfere with the electron capture analysis.
4.4 Interferences by phthalate esters can pose a major problem in pesti-
cide analysis when using the ECD. These compounds generally appear
in the chromatogram as large peaks. Common flexible plastics
contain varying amounts of phthalates, that are easily extracted or
leached during laboratory operations. Cross contamination of clean
glassware routinely occurs when plastics are handled during
extraction steps, especially when solvent-wetted surfaces are
handled. Interferences from phthalates can best be minimized by
avoiding the use of plastics in the laboratory. Exhaustive
purification of reagents and glassware may be required to eliminate
background phthalate contamination.(1)
4.5 Interfering contamination may occur when a sample containing low
concentrations of analytes is analyzed immediately following a
sample containing relatively high concentrations of analytes.
Between-sample rinsing of the sample syringe and associated
equipment with methyl-t-butyl-ether (MTBE) can minimize sample cross
contamination. After analysis of a sample containing high
concentrations of analytes, one or more injections of MTBE should be
made to ensure that accurate values are obtained for the next
sample.
4.6 Matrix interferences may be caused by contaminants that are
coextracted from the sample. Also, note that all analytes listed in
the Scope and Application Section are not resolved from each other
on any one column, i.e., one analyte of interest may be an
interferant for another analyte of interest. The extent of matrix
interferences will vary considerably from source to source,
depending upon the water sampled. The procedures in Sect. 11 can be
used to overcome many of these interferences. Positive
identifications should be confirmed (Sect. 11.9).
4.7 It is important that samples and working standards be contained in
the same solvent. The solvent for working standards must be the
same as the final solvent used in sample preparation. If this is
not the case, chromatographic comparability of standards to sample
may be affected.
5. SAFETY
5.1 The toxicity or carcinogenicity of each reagent used in this method
has not been precisely defined; however, each chemical compound'must
be treated as a potential health hazard. Accordingly, exposure to
these chemicals must be reduced; to the lowest possible level. The
laboratory is responsible for maintaining a current awareness file
of OSHA regulations regarding the safe handling of the chemicals
specified in this method. A reference file of material safety data
sheets should also be made available to all personnel involved in
515.1-6
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the chemical analysis. Additional references to laboratory safety
are available and have been identified (2-4) for the information of
the analyst. '
5.2 DIAZOMETHANE — A toxic carcinogen which can explode under certain
conditions. The following precautions must be followed:
5.2.1 Use only a well ventilated hood — do not breath vapors.
5.2,2 Use a safety screen.
5.2.3 Use mechanical pipetting aides.
5.2.4 Do not heat above 90°C — EXPLOSION may result.
5.2.5 Avoid grinding surfaces, ground glass joints, sleeve
bearings, glass stirrers — EXPLOSION may result.
5.2.6 Store away from alkali metals — EXPLOSION may result.
5.2.7 Solutions of diazomethane decompose rapidly in the presence
of solid materials such as copper powder, calcium chloride
and boiling chips. '
5.2.8 The diazomethane generation apparatus used in the
esterification procedures (Sect. 11.4 and 11.5) produces
micromolar amounts of diazomethane to minimize safety
hazards.
5.3 ETHYL ETHER — Nanograde, redistilled in glass, if necessary.
5.3.1 Ethyl ether is an extremely flammable solvent. If a
mechanical device is used for sample extraction, the device
should be equipped with an explosion-proof motor and placed
in a hood to avoid possible damage and injury due to an
explosion.
5.3.2 Ethyl ether must be free of peroxides as indicated by EM
Quant test strips (available from Scientific Products Co
Cat. No. PI 126-8, and other suppliers).
5.4 WARNING: When a solvent is purified, stabilizers added by the
manufacturer are removed, thus potentially making the solvent
hazardous.
EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.)
6.1 SAMPLE BOTTLE — Borosil icate, 1-L volume with graduations (Wheaton
Media/Lab bottle 219820 or equivalent), fitted with screw caps lined
with TFE-fluorocarbon. Protect samples from light. The container
must be washed and dried as described in Sect. 4.1.1 before use to
minimize contamination. Cap liners are cut to fit from sheets
515.1-7
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(Pierce Catalog No. 012736) and extracted with methanol overnight
prior to use.
6.2 GLASSWARE
6.2.1 Separatory funnel — 2000-mL, ;with TFE-fluorocarbon stop-
cocks, ground glass or TFE-flilorocarbon stoppers.
6.2.2 Tumbler bottle — 1.7-L (Wheaton Roller Culture Vessel or
equivalent), with TFE-fluorocarbon lined screw cap. Cap
liners are cut to fit from sheets (Pierce Catalog No. 012736)
and extracted with methanol overnight prior to use.
6.2.3 Concentrator tube, Kuderna-Danish (K-D) — 10- or 25-mL,
graduated (Kontes K-570050-2525 or Kontes K-570050-1025 or
equivalent). Calibration must be checked at the volumes
employed in the test. Ground ;glass stoppers are used to
prevent evaporation of extracts.
6.2.4 Evaporative flask, K-D — 500-mL (Kontes K-570001-0500 or
equivalent). Attach to concentrator tube with springs.
6.2.5 Snyder column, K-D — three-ball macro (Kontes K-503000-0121
or equivalent).
6.2.6 Snyder column, K-D — two-ball micro (Kontes K-569001-0219 or
equivalent).
6.2.7 Flask, round-bottom — 500-mL with 24/40 ground glass joint.
6.2.8 Vials — glass, 5- to 10-mL capacity with TFE-fluorocarbon
lined screw cap.
6.2.9 Disposable pipets — sterile plugged borosilicate glass, 5-mL
capacity (Corning 7078-5N or equivalent).
6.3 SEPARATORY FUNNEL SHAKER — Capable of holding 2-L separatory
funnels and shaking them with rocking motion to achieve thorough
mixing of separatory funnel contents (available from Eberbach Co. in
Ann Arbor, MI or other suppliers).
6.4 TUMBLER — Capable of holding tumbler bottles and tumbling them
end-over-end at 30 turns/min (Associated Design and Mfg. Co.,
Alexandria, VA and other suppliers).
6.5 BOILING STONES — Teflon, Chemware (Norton Performance Plastics No.
015021 and other suppliers).
6.6 WATER BATH — Heated, capable of temperature control (± 2°C). The
bath should be used in a hood.
6.7 BALANCE — Analytical, capable of accurately weighing to the nearest
0.0001 g.
515.1-8
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6.8 DIAZOMETHANE GENERATOR — Assemble from two 20 x 150 mm test tubes,
two Neoprene rubber stoppers, and a source of nitrogen as shown in
Figure 1 (available from Aldrich Chemical Co.)- When esterification
is performed using diazomethane solution, the diazomethane collector
is cooled in an approximately 2-L thermos for ice bath or a
cryogenically cooled vessel (Thermoelectrics Unlimited Model SK-12
or equivalent). .
6.9 GLASS WOOL — Acid washed (Supelco 2-0383 or equivalent) and heated
at 450°C for 4 hr.
6.10 GAS CHROMATOGRAPH — Analytical system complete with temperature
programmable GC suitable for use with capillary columns and all
required accessories including syringes, analytical columns, gases,
detector and stripchart recorder or computerized data system. A
data system is recommended for measuring peak areas. Table 1 lists ,
retention times observed for method analytes using the columns and
analytical conditions described below.
6.10.1 Column 1 (Primary column) — 30 m long x 0.25 mm I.D. DB-5
bonded fused silica column, 0.25 fim film thickness (J&W
Scientific). Helium carrier gas flow is established at 30
cm/sec linear velocity and oven temperature is programmed
from 60°C to 300°C at 4°C/min. Data presented in this method
were obtained using this column. The injection volume was
2 ill splitless mode with 45 second delay. The injector
temperature was 250°C and the detector was 320°C. Alterna-
tive columns may be used in accordance with the provisions
described in Sect. 9.4.
6.10.2 Column 2 (Confirmation column) — 30 m long x 0.25 mm I.D.
DB-1701 bonded fused silica column, 0.25 /im film thickness
(J&W Scientific). Helium carrier gas flow is established at
30 cm/sec linear velocity and oven temperature is programmed
from 60°C to 300°C at 4°C/min.
6.10.3 Detector — Electron capture. This detector has proven
effective in the analysis of method analytes in fortified
reagent and artificial ground waters.
REAGENTS AND STANDARDS - WARNING: When a solvent is purified,
stabilizers added by the manufacturer are removed, thus potentially
making the solvent hazardous. Also, when a solvent is purified,
preservatives added by the manufacturer are removed, thus potentially
reducing the shelf-life.
7.1 ACETONE, METHANOL, METHYLENE CHLORIDE, MTBE — Pesticide quality or
equivalent.
7.2 ETHYL ETHER, UNPRESERVED — Nanograde, redistilled in glass if
necessary. Must be free of peroxides as indicated by EM Quant test
strips (available from Scientific Products Co., Cat. No. PI126-8,
and other suppliers). Procedures recommended for removal of per-
oxides are provided with the test strips.
515.1-9
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7.3 SODIUM SULFATE, GRANULAR, ANHYDROUS, ACS GRADE — Heat treat in a
shallow tray at 450°C for a minimum of 4 hr to remove interfering
organic substances. Acidify by slurrying 100 g sodium sulfate with
enough ethyl ether to just cover the solid. Add 0.1 ml concentrated
sulfuric acid and m-ix thoroughly. ;Remove the ether under vacuum.
Mix 1 g of the resulting solid with 5 ml of reagent water and
measure the pH of the mixture. The pH must be below pH 4. Store at
130°C.
7.4 SODIUM THIOSULFATE, GRANULAR, ANHYDROUS — ACS grade.
7.5 SODIUM HYDROXIDE (NAOH), PELLETS — ACS grade.
7.5.1 NaOH, 6 N — Dissolve 216 g NaOH in 900 mL reagent water.
7.6 SULFURIC ACID, CONCENTRATED — ACS grade, so. gr. 1.84.
7.6.1 Sulfuric acid, 12 N — Slowly add 335 mL concentrated
sulfuric acid to 665 mL of reagent water.
7.7 POTASSIUM HYDROXIDE (KOH), PELLETS — ACS grade.
7.7.1 KOH, 37% (w/v) — Dissolve 37 g KOH pellets in reagent water
and dilute to 100 mL.
7.8 CARBITOL (DIETHYLENE GLYCOL MONOETHYL ETHER) — ACS grade.
Available from Aldrich Chemical Co.
7.9 DIAZALD, ACS grade — Available from Aldrich Chemical Co.
7.10 DIAZALD SOLUTION — Prepare a solution containing 10 g Diazald in
100 mL of a 50:50 by volume mixture of ethyl ether and carbitol.
This solution is stable for one month or longer when stored at 4°C
in an amber bottle with a Teflon-lined screw cap.
7.11 TRIMETHYLSILYLDIAZOMETHANE (TMSD) — Available from Aldrich Chemical
Co. as a 2 molar solution in hexane. TMSD is stable during storage
in this solution.
7.12 SODIUM CHLORIDE (NACL), CRYSTAL, ACS GRADE — Heat treat in a
shallow tray at 450°C for a minimum of 4 hr to remove interfering
organic substances.
7.13 4,4'-DIBROMOOCTAFLUOROBIPHENYL (DBOB) — 99% purity, for use as
internal standard (available from Aldrich Chemical Co).
7.14 2,4-DICHLOROPHENYLACETIC ACID (DCAA) — 99% purity, for use as
surrogate standard (available from Aldrich Chemical Co).
7.15 MERCURIC CHLORIDE -- ACS grade (Aldrich Chemical Co.) - for use as a
bacteriocide (optional- see Section 8).
7.16 REAGENT WATER — Reagent water is defined as water that is
reasonably free of contamination that would prevent the
515.1-10
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determination of any analyte of interest. Reagent water used to
generate the validation data in this method was distilled water
obtained from the Magnetic Springs Water Co., Columbus, Ohio.
7.17 SILICIC ACID, ACS GRADE.
7.18 FLORISIL - 60-100/PR mesh (Sigma No. F-9127). Activate by heating
in a shallow container at 150°C for at least 24 and not more than 48
hr.
7.19 STOCK STANDARD SOLUTIONS (1.00 /zg/pL) - Stock standard solutions
may be purchased as certified solutions or prepared from pure
standard materials using the following procedure:
7.19.1 Prepare stock standard solutions by accurately wei.ghing
approximately 0.0100 g of pure material. Dissolve the
material in MTBE and dilute to volume in a 10-mL volumetric
flask. Larger volumes may be used at the convenience of the
analyst. If compound purity is certified at 96% or greater,
the weight may be used without correction to calculate the
concentration of the stock standard. Commercially prepared
stock standards may be used at any concentration if they are
certified by the manufacturer or by an independent source.
7.19.2 Transfer the stock standard solutions into TFE-fluoro-
carbon-sealed screw cap amber vials. Store at room tempera-
ture and protect from light.
7.19.3 Stock standard solutions should be replaced after two months
or. sooner if comparison with laboratory fortified blanks or
QC samples indicate a problem.
7.20 INTERNAL STANDARD SOLUTION - Prepare an internal standard solution "
by accurately weighing approximately 0.0010 g of pure DBOB
Dissolve the DBOB in MTBE and dilute to volume in a 10-mL volumetric
flask. Transfer the internal standard solution to a TFE-fluoro-
carbon-sealed screw cap bottle and store at room temperature
Addition of 25 /iL of the internal standard solution to 10 mL of
sample extract, or 12.5 jjl to 5 mL of sample extract, results in a
final internal standard concentration of 0.25 /ig/mL. Solution
should be replaced when ongoing QC (Sect. 9) indicates a problem.
Note that DBOB has been shown to be an effective internal standard
for the method analytes, but other compounds may be used if the
quality control requirements in Sect. 9 are met.
7.21 SURROGATE STANDARD SOLUTION - Prepare a surrogate standard solution
by accurately weighing approximately 0.0010 g of pure DCAA
Dissolve the DCAA in MTBE and dilute to volume in a 10-mL volumetric
flask. Transfer the surrogate standard solution to a TFE-fluoro-
carbon-sealed screw cap bottle and store at room temperature.
Addition of 50 /zL of the surrogate standard solution to a 1-L sample
prior to extraction results in a surrogate standard concentration in
the sample of 5 /ig/L and, assuming quantitative recovery of DCAA, a
surrogate standard concentration in the final extract of 0.5 /ig/mL.
515.1-11
-------
Solution should be replaced when ongoing QC (Sect. 9) indicates a
problem. Note DCAA has been shown to be an effective surrogate
standard for the method analytes, but other compounds may be used if
the quality control requirements in Sect. 9 are met.
7.22 LABORATORY PERFORMANCE CHECK SOLUTIONS — Prep.are a diluted dinoseb
solution by adding 10 nl of the 1.0 M9/ML dinoseb stock solution to
the MTBE and diluting to volume in a 10-mL volumetric flask. To
prepare the check solution, add 40 til of the diluted dinoseb
solution, 16 ML of the 4-nitrophenol stock solution, 6 /zL of the
3,5-dichlorobenzoic acid stock solution, 50 p.1 of the surrogate
standard solution, 25 juL of the internal standard solution, and 250
III of methanol to a 5-mL volumetric flask and dilute to volume with
MTBE. Methylate sample as described in Sects. 11.4 or 11.5. Dilute
the sample to 10 mL in MTBE. Transfer to a TFE-fluorocarbon-sealed
screw cap bottle and store at room temperature. Solution should be
replaced when ongoing QC (Sect. 9) indicates a problem.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 Grab samples must be collected in glass containers. - Conventional
sampling practices (5) should be followed; however, the bottle must
not be prerinsed with sample before collection.
8.2 SAMPLE PRESERVATION AND STORAGE
8.2.1 If residual chlorine is present, add 80 mg of sodium
thiosulfate (or 50 mg sodium sulfite) per liter of sample to
the sample bottle prior to collecting the sample.
8.2.2 After the sample is collected in a bottle containing the
dechlorinating agent, seal the, bottle and shake until
dissolved.
8.2.3 The samples must be iced or refrigerated at 4°C away from
light from the time of collection until extraction. Pre-
servation study results indicated that most method analytes
present in samples were stable for 14 days when stored under
these conditions. Analyte stability may be affected by the
matrix; therefore, the analyst should verify that the
preservation technique is applicable to the samples under
study.
8.2.4 All performance data presented in this method are from
samples preserved with mercuric chloride. No suitable
preservation agent (biocide) has been found other than
mercuric-chloride. However the use of mercuric chloride is
not required due to its toxlcity and potential harm to the
environment.
8.2.5 In some circumstances where biological degradation of target
pesticides might be expected, use of mercuric chloride may be
appropriate to minimize the possibility of false-negative
results. If mercuric chloride is to be used, add it (Sect.
515.1-12
-------
7.8) to the sample bottle in amounts to produce a
concentration of 10 mg/L. Add 1 mL of a solution containing
10 mg/mL of mercuric chloride in reagent water to the sample
bottle at the sampling site or in the laboratory before
shipping to the sampling site. A major disadvantage of
mercuric chloride is that it is a highly toxic chemical;
mercuric chloride must be handled with caution, and samples
containing mercuric chloride must be disposed of properly.
8.3 EXTRACT STORAGE
8.3.1 Extracts should be stored at 4°C away from light.
Preservation study results indicate that most analytes are
stable for 28 days; however, the analyst should verify
appropriate extract holding times applicable to the samples
under study.
9. QUALITY CONTROL
9_.l Minimum quality control (QC) requirements are initial demonstration
of laboratory capability, determination of surrogate compound
recoveries in each sample and blank, monitoring internal standard
peak area or height in each sample and blank (when internal standard
calibration procedures are being employed), analysis of laboratory
reagent blanks, laboratory fortified samples, laboratory fortified
blanks, and QC samples. A MDL for each analyte must also be
determined.
9.2 LABORATORY REAGENT BLANKS (LRB). .Before processing any samples, the
analyst must demonstrate that all glassware and reagent
interferences are under control. Each time a set of samples is
extracted or reagents are changed, a LRB must be analyzed. If
within the retention time window of any analyte the LRB produces a
peak that would prevent the determination of that analyte, determine
the source of contamination and eliminate the interference before
processing samples.
9.3 INITIAL DEMONSTRATION OF CAPABILITY.
9.3.1 Select a representative fortified concentration for each
analyte. Suggested concentrations are 10 times the EDL or a
concentration that represents a mid-point in the calibration
range. Prepare a primary dilution standard (in methanol)
containing each analyte at 1000 times selected concentration.
With a syringe, add 1 mL of the concentrate to each of four
to seven 1-L aliquots 'of reagent water, and analyze each
aliquot according to procedures beginning in Sect. 11.
9.3.2 For each analyte the recovery value for all of these samples
must fall in the range of ± 30% of the fortified amount, with
the RSD of the measurements 30% or less. For those compounds
that meet the acceptable criteria, performance is considered
acceptable and sample analysis may begin. For those
compounds that fail these criteria, this procedure must be
515.1-13
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reported using fresh samples' until satisfactory performance
has been demonstrated.
9.3.3 For each analyte, determine the MDL. Prepare a minimum of 7
LFBs at a low concentration. Fortification concentrations in
Table 3 may be used as a guide, or use calibration data
obtained in Section 10 to estimate a concentration for each
analyte that, will produce a peak with a 3-5 times signal to
noise response. Extract and analyze each replicate according
to Sections 11 and 12. It is recommended that these LFBs be
prepared and analyzed over a period of several days, so that
day to day variations are reflected in precision
measurements. Calculate mean recovery and standard deviation
for each analyte. Use the standard deviation and the equation
given in Table 3 to calculate the MDL.
9.3.4 The initial demonstration of capability is used primarily to
preclude a laboratory from analyzing unknown samples via a
new, unfamiliar method prior to obtaining some experience
with it. It is expected that as laboratory personnel gain
experience with this method the quality of data will improve
beyond those required here.
9.4 The analyst is permitted to modify GC columns, GC conditions,
concentration techniques (i.e., evaporation techniques), internal
standard or surrogate compounds. Each time such method
modifications are made, the analyst must repeat the procedures in
Sect. 9.3
9.5 ASSESSING SURROGATE RECOVERY.
9.5.1 When surrogate recovery from a sample or method blank is <70%
or >130%, check (1) calculations to locate possible errors,
(2) standard solutions for degradation, (3) contamination,
and (4) instrument performance. If those steps do not reveal
the cause of the problem, reanalyze the extract.
9.5.2 If a LRB extract reanalysis fails the 70-130% recovery
criterion, the problem must [be identified and corrected
before continuing. '
9.5.3 If sample extract reanaTysis meets the surrogate recovery
criterion, report only data for the reanalyzed extract. If
sample extract continues to fail the recovery criterion,
report all data for that sample as suspect.
9.6 ASSESSING THE INTERNAL STANDARD
9.6.1 When using the internal standard calibration procedure, the
analyst must monitor the IS response (peak area or peak
height) of all samples during each analysis day. The IS
response for any sample chromatogram should not deviate from
the daily calibration check standard's IS response by more
than 30%. j
515.1-14
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9.6.2 If >30% deviation occurs with an individual extract optimize
instrument performance and inject a second aliquot of that
extract.
9.6.2.1 If the reinjected aliquot produces an acceptable
internal standard response, report results for that
aliquot.
9.6.2.2 If a deviation of greater than 30% is obtained for
the reinjected extract, analysis of the samples
should be repeated beginning with Sect. 11, provided
the sample is still available. Otherwise, report
results obtained from the reinjected extract, but
annotate as suspect.
9.6.3 If consecutive samples fail the IS response acceptance
criterion, immediately analyze a calibration check standard.
9.6.3.1 If the check standard provides a response within 20%
of the predicted value,, then follow procedures
itemized in Sect. 9.6.2 for each sample failing the
IS response criterion.
9.6.3.2 If the check standard provides a response which
deviates more than 20% of the predicted value, then
the analyst must recalibrate, as specified in Sect.
9.7 ASSESSING LABORATORY PERFORMANCE - LABORATORY FORTIFIED BLANK
9.7.1 The laboratory must analyze at least one laboratory fortified
blank (LFB) sample with every 20 samples or one per sample
set (all samples extracted within a 24-hr period) whichever
is greater. The concentration of each analyte in the LFB
should be 10 times EDL or a concentration which represents a
mid-point in the calibration. Calculate accuracy as percent
• recovery (X,-). If the recovery of any analyte falls outside
the control limits (see Sect. 9.7.2), that analyte is judged
out of control, and the source of the problem should be
identified and resolved before continuing analyses.
9.7.2 Until sufficient data .become available from within their own
laboratory, usually a minimum of results from 20 to 30
analyses, the laboratory should assess laboratory performance
against the control limits in Sect. 9.3.2 that are derived
from the data in Table, 2. When sufficient internal
performance data becomes available, develop control limits
from the mean percent recovery (X) and standard deviation (S)
of the percent recovery. These data are used to establish
.upper and lower control limits as follows:
UPPER CONTROL LIMIT = X + 3S
LOWER CONTROL LIMIT = X - 3S
515.1-15
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After each five to ten new recovery measurements, new control
limits should be calculated using only the most recent 20-30
data points. These calculated control limits should not
exceed those established in Section 9.3.2.
9.7.3 It is recommended that the laboratory periodically determine
and document its detection limit capabilities for the
analytes of interest.
9.7.4 At least quarterly, analyze a QC sample from an outside
source.
9.8 ASSESSING ANALYTE RECOVERY - LABORATORY .FORTIFIED SAMPLE MATRIX
9.8.1 The laboratory must add a known concentration to a minimum of
10% of the routine samples or one sample per set, whichever
is greater. The concentration should not be less then the
background concentration of the sample selected for
fortification. Ideally, the concentration should be the same
as that used for the laboratory fortified blank (Sect. 9.7).
Over time, samples from -all routine sample sources should be
fortified.
.9.8.2 Calculate the percent recovery, P, of the concentration for
each analyte, after correcting the analytical result, X, from
the fortified sample for the background concentration, b,
measured in the unfortified sample, i.e.,:
P = 100 (X - b) / fortifying concentration,
I
and compare these values to control limits appropriate for
reagent water data collected in the same fashion. The value
for P must fall between 6536-135% of'the fortified
concentration.
9.8.3 If the recovery of any such'analyte falls outside the
designated range, and the laboratory performance for that
analyte is shown to be in Control (Sect. 9.7), the recovery
problem encountered with the fortified sample is judged to be
matrix related, not system related. The result for that
analyte in the unfortified sample is labeled suspect/matrix
to inform the data user that the results are suspect due to
matrix effects.
9.9 ASSESSING INSTRUMENT SYSTEM - LABORATORY PERFORMANCE CHECK SAMPLE -
Instrument performance should be monitored on a daily basis by
analysis of the LPC sample. The LPC sample contains compounds
designed to monitor instrument sensitivity, column performance
(primary column) and chromatographic performance. LPC sample
components and performance criteria are listed in Table 4.
Inability to demonstrate acceptable instrument performance indicates
the need for reevaluation of the instrument system. The sensitivity
requirements are set based on the EDLs published in this method. If
laboratory EDLs differ from those listed in this method,
515.1-16
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concentrations of the LPC compounds must be adjusted to be
compatible with the laboratory EDLs.
9.10 The laboratory may adopt additional quality control practices for
use with this method. The specific practices that are most
productive depend upon the needs of the laboratory and the nature of
the' samples. For example, field or laboratory duplicates may be
analyzed to assess the precision of the environmental measurements
or field reagent blanks may be used to assess contamination of
samples under site conditions, transportation and storage.
10. CALIBRATION AND STANDARDIZATION
10.1 Establish GC operating parameters equivalent to those indicated in
Sect. 6.10. The GC system may be calibrated using either the
internal standard technique (Sect. 10.2) or the external standard
technique (Sect. 10.3). NOTE: Calibration standard solutions must
be prepared such .that no unresolved analytes are mixed together.
.10.2 INTERNAL STANDARD CALIBRATION PROCEDURE — To use this approach, the
analyst must select one or more internal standards compatible in
analytical behavior to the compounds of interest. The analyst must
further demonstrate that the measurement of the internal standard is
not affected by method or matrix interferences. DBOB has been
identified as a suitable internal standard.
10.2.1 Prepare calibration standards at a minimum, of three
(recommend five) concentration levels for each analyte of
interest by adding volumes of one or more stock standards to
a volumetric,flask. To each calibration standard, add a
known constant amount of one or more of the internal
standards and 250 jiiL methanol, and dilute to volume with
,MTBE. Esterify acids with diazomethane as described in Sect.
11.4 or 11.5.
Guidance on the number of standards is as follows: A minimum
of three calibration standards are required to calibrate a
range of a factor of 20 in concentration. For a factor of 50
use at least four standards, and for a factor of 100 at least
five standards. One calibration standard should contain each
analyte of concern at a concentration 2 to 10 times greater
. than the method detection limit for that compound. The other
calibration standards should contain each analyte of concern
at concentrations that define the range of the sample analyte
concentrations or should define the working range of the
detector. . .
10.2.2 Analyze each calibration standard according to the procedure
(Sect. 11.9). Tabulate response (peak height or area)
against concentration for each,compound and internal
standard. Calculate the response factor (RF) for each
. , -' analyte and surrogate using Equation 1. ,
515.1-17
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RF =
(As)
(Ais) (Cs)
where:
Equation 1
c"
= Response for the analyte to be measured.
= Response for the internal standard.
= Concentration of the internal standard (/ig/L)
= Concentration of the analyte to be measured
(M9/L).
10.2.3 If the RF value over the working range is constant (20% RSD
or less) the average RF can be used for calculations. Alter-
natively, the results can be used to plot a calibration curve
of response ratios (As/Ajs) vs. Cs.
10.2.4 The working calibration curve or RF must be verified on each
working day by the measurement of a minimum of two calibra-
tion check standards, one at the beginning and one at the end
of the analysis day. These check standards should be at two
different concentration levels to verify the calibration
curve. For extended periods of analysis (greater than 8 hr),
it is strongly recommended that check standards be inter-
spersed with samples at regular intervals during the course
of the analyses. If the response for any analyte varies from
the predicted response by more than + 20%, the test must be
repeated using a fresh calibration standard. If the results
still do not agree, generate a new calibration curve. For
those analytes that failed the calibration verification,
results from field samples analyzed since the last passing
calibration should be considered suspect. Reanalyze sample
extracts for these analytes after acceptable calibration is
restored.
10.3 EXTERNAL STANDARD CALIBRATION PROCEDURE
10.3.1 Prepare calibration standard^ as described in Sect 10.2.1,
omitting the use of an internal standard.
10.3.2 Starting with the standard of lowest concentration, analyze
each calibration standard according to Sect. 11.9 and tabu-
late response (peak height or area) versus the concentration
in the standard. The results can be used to prepare a cali-
bration curve for each compound. Alternatively, if the ratio
of response to concentration (calibration factor) is a con-
stant over the working range (20% RSD or less), linearity
through the origin can be assumed and the average ratio or
calibration factor can be used in place of a calibration
curve.
10.3.3 The working calibration curve or calibration factor must be
verified on each working day as described in Section 10.2.4.
515.1-18
-------
10.4 Verify calibration standards periodically, recommend at least
quarterly, by analyzing a standard prepared from reference material
obtained from an independent source. Results from these analyses
must be within the limits used to routinely check calibration
11. PROCEDURE
11.1 MANUAL HYDROLYSIS, PREPARATION, AND EXTRACTION.
11.1.1 Add preservative(s) (Sect.8) to LRBs and LFBs. Mark the
water meniscus on the side of the sample bottle for later.
determination of sample volume (Sect. 11.1.9). Pour the
entire sample into a 2-L separatory funnel. Fortify sample
with 50 fil of the surrogate standard solution.
11.1.2 Add 250 g NaCl to the sample, seal, and shake to dissolve
salt.
11.1.3 Add 17 mL of 6 N NaOH to the sample, seal, and shake. Check
the pH of the sample with pH paper; if the sample does not
have a pH greater than or equal to 12, adjust the pH by
adding more 6 N NaOH. Let the sample sit at room temperature
for 1 hr, shaking the separatory funnel and contents
periodically. Note: Since many of the analytes contained in
this method are applied as a variety of esters and salts, it
is vital to hydrolyze them to the parent acid prior to
extraction. This step must be included in the analysis of
all extracted field samples, LRBs, LFBs, LFMs, and QCS.
11.1.4 Add 60 mL methylene chloride to the sample bottle to rinse
the bottle, transfer the methylene chloride to the separatory
funnel and extract the sample by vigorously shaking the
funnel for 2 min with periodic venting to release excess
pressure. Allow the organic layer to separate from the water
phase for a minimum of 10 min. If the emulsion interface
between layers is more than one-third the volume of the
solvent layer, the analyst must employ mechanical techniques
to complete the phase separation. The optimum technique
depends upon the sample, but may include stirring, filtration
through glass wool, centrifugation, or other physical
methods. Discard the methylene chloride phase (Sect. 14,15).
11.1.5 Add a second 60-mL volume of methylene chloride to the sample
bottle and repeat the extraction procedure a second time,
discarding the methylene chloride layer. Perform a third
extraction in the same manner.
11.1.6 Add 17 mL of 12 N H2S04 to the sample, seal, and shake to
mix. Check the pH of the sample with pH paper; if the sample
does not have a pH less than or equal to 2, adjust the pH by
adding more 12 N H2S04.
11.1.7 Add 120 mL ethyl ether to the sample, seal, and extract the
sample by vigorously shaking the funnel for 2 min with
515.1-19 -
-------
periodic venting to release excess pressure. Allow the
organic layer to separate from the water phase for a minimum
of 10 min. If the emulsion interface between layers is more
than one third the volume of the solvent layer, the analyst
must employ mechanical techniques to complete the phase
separation. The optimum technique depends upon the sample,
but may include stirring, filtration through glass wool,
centrifugation, or other physical methods. Remove the
aqueous phase to a 2-L Erlenmeyer flask and collect the ethyl
ether phase in a 500-mL round-bottom flask containing
approximately 10 g of acidified anhydrous sodium sulfate.
Periodically, vigorously shake the sample and drying agent.
Allow the extract to remain in contact with the sodium
sulfate for approximately 2 hours.
11.1.8 Return the aqueous phase to the separatory funnel, add a
60-mL volume of ethyl ether to the sample, and repeat the
extraction procedure a second time, combining the extracts in
the 500-mL erlenmeyer flask: Perform a third extraction with
60 ml of ethyl ether in the!same manner.
11.1.9 Determine the original.sample volume by refilling the sample
bottle to the mark and transferring the water to a 1000-mL
graduated cylinder. Record'the sample volume to the nearest
5 ml.
11.2 AUTOMATED HYDROLYSIS, PREPARATION, AND EXTRACTION. — Data presented
in this method were generated using the automated extraction
procedure with the mechanical separatory funnel shaker.
11.2.1 Add preservative (Sect. 8.2) to any samples not previously
preserved, e.g., LRBs and LFBs. Mark,the water meniscus on
the side of the sample bottle for later determination of
sample volume (Sect. 11.2.9). Fortify sample with 50 /zL of
the surrogate standard solution. If the mechanical
separatory funnel shaker is used, pour the entire sample into
a 2-L separatory funnel. If the mechanical tumbler is used,
pour the entire sample into a tumbler bottle.
11.2.2 Add 250 g NaCl to the sample, seal, and shake to dissolve
salt.
11.2.3 Add 17 mL of 6 N NaOH to the sample, seal, and shake. Check
the pH of the sample with pH paper; if the sample does not
have a pH greater than or equal to 12, adjust the pH by
adding more 6 N NaOH. Shake sample for 1 hr using the
appropriate mechanical mixing device. Note: Since many of
the analytes contained in this method are applied as a
variety of esters and salts, it is vital to hydrolyze them to
the parent acid prior to extraction. This step must be
included in the analysis of all extracted field samples,
LRBs, LFBs, LFMs, and QCS. ;
515.1-20
-------
11.2.4 Add 300 ml methylene chloride to the sample bottle to rinse
the bottle, transfer the methylene chloride to the separatory
funnel or tumbler bottle, seal, and shake for 10 s, venting
periodically. Repeat shaking and venting until pressure
release is not observed during venting. Reseal and place
sample container in appropriate mechanical mixing device.
Shake or tumble the sample for 1 hr. Complete and thorough
mixing of the organic and aqueous phases should be observed
at least 2 min after starting the mixing device.
11.2.5 Remove the sample container from the mixing device. If the
tumbler is used, pour contents of tumbler bottle into a 2-L
separatory funnel. Allow the organic layer to separate from
the water phase for a minimum of 10 min. If the emulsion
interface between layers is more than one third the volume of
the solvent layer, the analyst must employ mechanical
techniques to complete the phase separation. The optimum
technique depends upon the sample, but may include stirring,
filtration through glass wool, centrifugation, or other
physical methods. Drain and discard the organic p.hase. If
the tumbler is used, return the aqueous phase to the tumbler
bottle.
11.2.6 Add 17 ml of 12 N H2S04 to the sample, seal, and shake to
mix. Check the pH of the sample with pH paper; if the sample
does not have a pH less than or equal to 2, adjust the pH by
adding more 12 N H2S04.
11.2.7 Add 300 mL ethyl ether to the sample, seal, and shake for 10
s, venting periodically. Repeat shaking and venting until
pressure release is not observed during venting. Reseal and
place sample container in appropriate mechanical mixing
device. Shake or tumble sample for 1 hr. Complete and
thorough mixing of the organic and aqueous phases should be
observed at least 2 min after starting the mixing device.
11.2.8 Remove the sample container from the mixing device. If the
tumbler is used, pour contents of tumbler bottle into a 2-L
separatory funnel. Allow the organic layer to separate from
the water phase for a minimum of 10 min. If the emulsion
interface between layers is more than one third the volume of
the solvent layer, the analyst must employ mechanical
techniques to complete the phase separation. The optimum
technique depends upon the sample, but may include stirring,
filtration through glass wool, centrifugation, or other
physical methods. Drain and discard the aqueous phase.
Collect the extract in a 500-mL round-bottom flask containing
about 10 g of acidified anhydrous sodium sulfate.
Periodically vigorously shake the sample and drying agent.
Allow the extract to remain in contact with the sodium
sulfate for approximately 2 hr.
11.2.9 Determine the original sample volume by refilling the sample
bottle to the mark and transferring the water to a 1000-mL
515.1-21,
-------
graduated cylinder. Record the sample volume to the nearest
5 ml.
11.3 EXTRACT CONCENTRATION
11.3.1 Assemble a K-D concentrator by attaching a concentrator tube
to a 500-mL evaporative flask.
11.3.2 Pour the dried extract through a funnel plugged with acid
washed glass wool, and collect the extract in the K-D
concentrator. Use a glass rod to crush any caked sodium
sulfate during the transfer. Rinse the round-bottom flask
and funnel with 20 to 30 ml of ethyl ether to complete the
quantitative transfer.
11.3.3 Add 1 to 2 clean boiling stones to the evaporative flask and
attach a macro Snyder column. Prewet the Snyder column by
adding about 1 mL ethyl ether to the top. Place the K-D
apparatus on a hot water bath, 60 to 65°C, so that the
concentrator tube is partially immersed in the hot water, and
the entire lower rounded surface of the flask is bathed with
hot vapor. At the proper rate of distillation the balls of
the column will actively chatter but the chambers will not
flood. When the apparent volume of liquid reaches 1 mL,
remove the K-D apparatus and allow it to drain and cool for
at least 10 min.
11.3.4 Remove the Snyder column and rinse the flask and its lower
joint into the concentrator tube with 1 to 2 mL of ethyl
ether. Add 2 mL of MTBE-and a fresh boiling stone. Attach a
micro-Snyder column to the concentrator tube and prewet the
column by adding about 0.5 ml. of ethyl ether to the top.
Place the micro K-D apparatus on the water bath so that the
concentrator tube is partially immersed in the hot water.
Adjust the vertical position of the apparatus and the water
temperature as required to complete concentration in 5 to 10
min. When the apparent volume of liquid reaches 0.5 mL,
remove the micro K-D from the bath and allow it to drain and
cool. Remove the micro Snyder column and add 250 p,i of
methanol. If the gaseous diazomethane procedure (Sect. 11.4)
or trimethylsilyldiazomethane procedure (11.6) is used for
esterification of pesticides; rinse the walls of the concen-
trator tube while adjusting the volume to 5.0 mL with MTBE.
If the pesticides will be esterified using the diazomethane
solution (Sect. 11.5), rinse the walls of the concentrator
tube while adjusting the volume to 4.5 mL with MTBE.
11.4 ESTERIFICATION OF ACIDS USING GASEOUS DIAZOMETHANE — Results
presented in this method were generated using the gaseous diazomet-
hane derivatization procedure. See Section 11.5 and 11.6 for
alternative procedures.
11.4.1 Assemble the diazomethane generator (Figure 1) in a hood.
515.1-22
-------
11.4.2 Add 5 mL of ethyl ether to Tube 1. Add 1 ml of ethyl ether,
1 ml of carbitol, 1.5 mL of 37% aqueous KOH, and 0.2 grams
Diazald to Tube 2. Immediately place the exit tube into the
concentrator tube containing the sample extract. Apply
nitrogen flow (10 mL/min) to bubble diazomethane through the
extract for 1 min. Remove first sample. Rinse the tip of
the diazomethane generator with ethyl ether after methylation
of each sample. Bubble diazomethane through the second
sample extract for 1 min. Diazomethane reaction mixture
should be used to esterify only two samples; prepare new
reaction mixture in Tube 2 to esterify each two additional
samples. Samples should turn yellow after addition of
diazomethane and remain yellow for at least 2 min. Repeat
methylation procedure if necessary.
11.4.3 Seal concentrator tubes with stoppers. Store at room
temperature in a hood for 30 min.
11.4.4 Destroy any unreacted diazomethane by adding 0.1 to 0.2 grams
silicic acid to the concentrator tubes. Allow to stand until
the evolution of nitrogen gas has stopped (approximately 20
min). Adjust the sample volume to 5.0. ml with MTBE.
11.5 ESTERIFICATION OF ACIDS USING DIAZOMETHANE SOLUTION — Alternative
procedure.
j*-
11.5.1 Assemble the diazomethane generator (Figure 2) in a hood.
The collection vessel is a 10- or 15-mL vial, equipped with a
Teflon-lined screw cap and maintained at 0-5C.
11.5.2 Add a sufficient amount of ethyl ether to tube 1 to cover the
first impinger. Add 5 mL of MTBE to the collection vial.
Set the nitrogen flow at 5-10 mL/min. Add 2 mL Diazald
solution (Sect. 7.10) and 1.5 mL of 37% KOH solution to the
second impinger. Connect the tubing as shown and allow the
nitrogen flow to purge the diazomethane from the reaction
vessel into the collection vial for 30 min. Cap the vial
when collection is complete and maintain at 0-5°C. When
stored at 0-5°C this diazomethane solution may be used over a
period of 48 hr.
11.5.3 To each concentrator tube containing sample or standard, add
0.5 mL diazomethane solution. Samples should turn yellow
after addition of the diazomethane solution and remain yellow
for at least 2 min. Repeat methylation procedure if
necessary.
11.5.4 Seal concentrator tubes with stoppers. Store at room
temperature in a hood for 30 min.
11.5.5 Destroy any unreacted diazomethane by adding 0.1 to 0.2 grams
silicic acid to the concentrator tubes. Allow to stand until
the evolution of nitrogen gas has stopped (approximately 20
min). Adjust the sample volume to 5.0 mL with MTBE.
515.1-23
-------
11.6 ESTERIFICATION OF ACIDS USING TRIMETHYLSILYLDIAZOMETHANE (TMSD) --
Alternative procedure. It should be noted that the gas
chromatographic background is increased when TMSD is used as the
derivatizing reagent instead of the generated diazomethane.
Although no method analyte is affected by this increased background,
the recommended surrogate, 2,4-dichloro-phenylacetic acid, is masked
by an interfering peak. This renders the surrogate useless at 1
//g/L or lower. »Any compound found suitable when TMSD is used is
acceptable as a surrogate.
11.6.1 Carry out the hydrolysis, clean-up, and extraction of the
method analytes as described up to Sect. 11.4.
11.6.2 Add 50 fil of the 2 M TMSD solution to each 5 ml sample
extract.
11.6.3 Place the tube containing the extract into a heating block at
50°C and heat the extract for 1 hour.
11.6.4 Allow the extract to cool to room temperature,- then add 100
/zL of 2 M acetic acid in methanol to react any excess TMSD.
11.6.5 Proceed with the identification and measurement of the
analytes using GC/ECD according to the procedures described
in the method.
11.7 FLORISIL SEPARATION (optional)
11.7.1 Place a small plug of glass-wool into a 5-mL disposable glass
pipet. Tare the pipet, and; measure 1 g of activated Florisil
• into the pipet.
11.7.2 Apply 5 mL of 5 percent metfianol in MTBE to the Florisil.
Allow the liquid to just re^ch the top of the Florisil. In
this and subsequent steps, allow the liquid level to just
reach the top of the Florisfil before applying the next rinse,
however, do not allow the Florisil to go dry. Discard
eluate.
11.7.3 Apply 5 mL methylated sample to the Florisil leaving silicic
acid in the tube. Collect eluate in K-D tube.
11.7.4 Add 1 ml of 5 percent methanol in MTBE to the sample
container, rinsing walls. Transfer the rinse to the Florisil
column leaving silicic acid in the tube. Collect eluate in a
K-D tube. Repeat with 1-mL and 3-mL aliquots of 5 percent
methanol in MTBE, collecting eluates in K-D tube.
11.7.5 If necessary, dilute eluate to 10 mL with 5 percent methanol
in MTBE.
11.7.6 Seal the vial and store in a refrigerator if further process-
ing will not be performed immediately. Analyze by GC-ECD.
515.1-24
-------
11.8 GAS CHROMATOGRAPHY
11.8.1 Sect. 6.10 summarizes the recommended operating conditions
for the GC. Included in Table 1 are retention times observed
using this method. Other GC columns or chromatographic
conditions may be used if the requirements of Sect. 9.3 are
met. ..'-..".
11.8.2 Calibrate qr verify the calibration of the system daily as
described in Sect. 10. The standards and extracts must be in
MTBE. .
11.8.3 If the internal standard calibration procedure is used,
fortify the extract with 25 . juL of internal standard solution.
Thoroughly mix sample and place aliquot in a GC vial for
subsequent analysis.
11.8.4 Inject 2 nl of the sample extract. Record the resulting peak
size in area units.
.11.8.5 If the response for the pe.ak exceeds the working range of the.
system, dilute the extract and reanalyze. If internal
standard calibration is used, add an additional amount of the
IS, so that the amount in the diluted extract will match the
calibration standards. . .'
11.9 IDENTIFICATION OF ANALYTES
11.9.1 Identify a sample component by comparison of its retention
time to the retention time of a reference chromatogram. If
the retention time of an unknown compound corresponds, within
limits, to the retention time of a standard compound, then
identification is considered positive.
11.9.2 The width of the retention time window used to make ,
identifications should be based upon measurements of actual
retention time variations of standards over the course of a
day. Three times the standard deviation .of a retention time
can be used to calculate a suggested window size for a
compound. However, the experience of the analyst should
weigh heavily in the interpretation of chromatograms.
11.9.3 Identification requires expert judgement when sample
components are not resolved chromatographically. When GC
peaks obviously represent more than one sample component
(i.e., broadened peak with shoulder(s) or valley between two
or more maxima, or any time doubt exists over the
identification of a peak on a chromatogram, appropriate
alternative techniques, to help confirm peak identifica-
tion, need to be employed. For example, more positive
identification may be made by the use of an alternative
detector which operates on a chemical/physical principle
different from that originally used, e.g., mass spectrom-
515.1-25
-------
etry, or the use of a second chromatography column. A
suggested alternative column in described in Sect. 6.10.
12. DATA ANALYSIS AND CALCULATIONS
12.1 Calculate analyte concentrations in the sample from the response for
the analyte using the calibration procedure described in Sect. 10.
Use the multi-point calibration to make all calculations. Do not
use the daily calibration verification data to quantitate analytes
in samples.
12.2 If the internal standard calibration procedure is used, calculate
the concentration (C) in the sample using the response factor (RF)
determined in Sect. 10.2 and Equation 2, or determine sample
concentration from the calibration curve.
(AS)(IS)
C (/ig/L) = Equation 2.
(Afs)(RF)(V0) i
where:
As = Response for the parameter'to be measured.
Ais = Response for the internal standard.
Is = Amount of internal standard added to each extract (/KJ).
V0 - Volume of water extracted (L).
j
12.3 If the external standard calibration procedure is used, calculate
the amount of material injected from the peak response using the
calibration curve or calibration^factor determined in Sect. JO.3.
The concentration (C) in the sample can be calculated from Equation
3.
(A)(Vt) ;
C (fig/I) = Equation 3.
(V,)(V.) ;
where:
A = Amount of material injected|(ng)
V; = Volume of extract injected
Vt = Volume of total extract (ill)
Vs = Volume of water extracted (mL).
13. METHOD PERFORMANCE ;
13.1 In a single laboratory, analyte recoveries from reagent water were
used to determine analyte MDLs, EDLs (Table 3) and demonstrate
method range. Analyte recoveries and standard deviation about the
percent recoveries at one concentration are given in Table 3. All
data in Tables 1-3 were obtained using diazomethane for
esterification.
515.1-26
-------
13.2 In a single laboratory, analyte recoveries from one standard
synthetic ground waters were determined at one concentration level.
Results were used to demonstrate applicability of the method to
different ground water matrices. Analyte recoveries from the one
synthetic matrix are given in Table 2.
13.3 The performance of dalapon using this method has been variable.
Different users have had varying success in the accuracy and
precision of dalapon measurements. Because the dalapon methyl ester
is much more volatile than the rest of the method analytes, it is
suspected that extract concentration technique may be involved with
poor recoveries of this analyte. Therefore it is recommended that
the analyst use caution to avoid losses due to volatization.
14. POLLUTION PREVENTION
14.1 This method uses significant volumes of organic solvents. It is
highly recommended that laboratories use solvent recovery systems to
recover used solvent as sample extracts are being concentrated.
Recovered solvents should be recycled or properly disposed of.
14.2 For information about pollution prevention that may be applicable to
laboratory operations, consult "Less is Better: Laboratory Chemical
Management for Waste Reduction" available from the American Chemical
Society's Department of Government Relations and Science Policy,
1155 16th Street N.W., Washington, D.C. 20036.
15. WASTE MANAGEMENT
15.1 It is the laboratory's responsibility to comply with all federal,
state, and local regulations governing waste management, particu-
larly the hazardous waste identification rules and land disposal
restrictions. The laboratory using this method has the responsi-
bility to protect the air, water, and land by minimizing and con-
trolling all releases from fume hoods and bench operations. Compli-
ance is also required with any sewage discharge permits and regula-
tions. For further information on waste management, consult "The
Waste Management Manual for Laboratory Personnel," also available
from the American Chemical Society at the address in Sect. 14.2.
16. REFERENCES
1. ASTM Annual Book of Standards, Part 11, Volume 11.02, D3694-82,
"Standard Practice for Preparation of Sample Containers and for
Preservation," American Society for Testing and Materials, Philadel-
phia, PA, p. 86, 1986.
2. "Carcinogens - Working with Carcinogens," Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77-206, Aug. 1977.
515.1-27
-------
3.
4.
5.
"OSHA Safety and Health Standards, General Industry," (29 CFR 1910),
Occupational Safety and Health Administration, OSHA 2206, (Revised,
January 1976). ,
"Safety in Academic Chemistry Laboratories," American Chemical
Society Publication, Committee on Chemical Safety, "ivo. EoA\Ao\\,
1979.
ASTM Annual Book of Standards, Part 11, Volume 11.01, D3370-82,
"Standard Practice for Sampling Water," American Society for Testing
and Materials, Philadelphia, PA, p. 130, 1986.
515.1-28
-------
TABLES. DIAGRAMS. FLOWCHARTS. AND VALIDATION DATA
TABLE I. RETENTION TIMES FOR METHOD ANALYTES
Analvte
Retention Time3
(minutes)
Primary Confirmation
Dalapon
3,5-Dichlorobenzoic acid
4-Nitrophenol
DCAA (surrogate)
Dicamba
Dichlorprop
2,4-D
D80B (int. std.)
Pentachlorophenol (PCP)
Chloramben
2,4,5-TP
5-Hydroxydicamba
2,4,5-T
2,4-DB
Dinoseb
Bentazon
Picloram
DCPA acid metabolites
Acifluorfen
3.4
18.6
18.6
22.0
22.1
25.0
25.5
27.5
28.3
29.7
29.7
30.0
30.5
32.2
32.4
33.3
34.4 •
35.8
41.5
4.7
17.7
20.5
14.9
22.6
25.6
27.0
27.6
27.0
32.8
29.5
30.7
30.9
32.2
34.1
34.6
37.5
37.8
42.8
Columns and analytical conditions are described in Sect. 6.10.1
and 6.10.2.
515.1-29
-------
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METHOD 515.2.
DETERMINATION OF CHLORINATED ACIDS IN WATER
USING LIQUID-SOLID EXTRACTION AND GAS
CHROMATOGRAPHY WITH AN ELECTRON CAPTURE DETECTOR
Revision 1.1
Edited by J.W. Munch (1995)
R.C. Dressman and J.J. Lichtenberg - EPA 600/4-81-053, Revision 1.0 (1981)
J.W. Hodgeson - Method 515, Revision 2.0 (1986)
T. Engel (Battelle Columbus Laboratories) - National Pesticide Survey
Method 3, Revision 3.0 (1987)
R.L. Graves - Method 515.1, Revision 4.0 (1989)
J.W. Hodgeson - Method 515.2, Revision 1.0 (1992)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
515.2-1
-------
METHOD 515.2
DETERMINATION OF CHLORINATED ACIDS IN WATER USING
LIQUID-SOLID EXTRACTION AND GAS CHROMATOGRAPHY
WITH AN ELECTRON CAPTURE DETECTOR
1. SCOPE AND APPLICATION
1.1
1.2
1.3
1.4
This is a gas chromatographic (GC) method applicable to the determi-
nation of certain chlorinated acids in ground water and finished
drinking water. The following compounds can be determined by this
method:
Chemical Abstract Services
Registry Number
50594-66-6
25057-89-0
94-75-7
94-82-6
1918-00-9
' 51-36-5 '
120-36-5
88-85-7
7600-50-2
87-86-5
1918-02-1
93-76-5
93-72-1
Analvte
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal acid metabolites l
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicamba
Pentachlorophenol (PCP)
Picloram
2,4,5-T
2,4,5-TP(Silvex)
(a> Dacthal monoacid and diacid metabolites included in method
scope; Dacthal diacid metabolite used for validation studies.
This method is applicable to the[determination of salts and esters
of analyte acids. The form of each acid is not distinguished by
this method. Results are calculated and reported for each listed
analyte as the total free acid.
Single.laboratory accuracy and precision data and method detection
"limits (MDLs) have been determined for the analytes above (Sect.
13). Observed detection limits may vary among water matrices,
depending upon the nature of interferences in the sample matrix and
the specific instrumentation used. , . .
This method is restricted to use by or under the supervision of
analysts experienced in the use of GC and in the interpretation of
gas chromatograms. Each analyst must demonstrate the ability to
generate acceptable results with this method using the procedure
described in Sect. 9.3.
515.2-2
-------
1.5 Analytes that are not separated chromatographically, (i.e., have
very similar retention times) cannot be individually identified and
measured in the same calibration mixture or water sample unless an
alternative technique for identification and quantitation exists
(Sect. 11.7).
1.6 When this method is used to analyze unfami!iar samples for any or
all of the analytes above, analyte identifications should be con-
firmed by analysis on a second gas chromatographic column or by gas
chromatography/mass spectrometry (GC/MS).
2. SUMMARY OF METHOD
2.1 A 250-mL measured volume of sample is adjusted to pH 12 with 6 N
sodium hydroxide for 1 hr to hydrolyze derivatives. ( Note: Since
many of the analytes contained in this method are applied as a
variety of esters and salts, it is,vital to hydrolyze them to the
parent acid prior to extraction.) Extraneous organic material is
removed by a-solvent wash. The sample is acidified, and the chlori-
nated acids are extracted with a 47 mm resin based extraction disk.
The acids are converted to their methyl esters using diazomethane or
alternatively, trimethylsilyldiazomethane (TMSD). Excess derivatiz-
ing reagent is removed, and the esters are determined by capillary
column GC using an electron capture detector (ECD). Analytes are
quantitated using procedural standard calibration (Sect. 3.14).
3. DEFINITIONS
3.1 INTERNAL STANDARD (IS) -- A pure analyte(s) added to a sample,
extract, or standard solution in known amount(s), and used to
measure the relative responses of other method analytes and surro-
gates that are components of the same sample or solution. The IS
must be an analyte that is not a sample component.
3.2 SURROGATE ANALYTE (SA) — A pure analyte(s), which is extremely
unlikely to be found in any sample, and which is added to a sample
aliquot in known amount(s) before extraction or other processing,
and is measured with the same procedures used to measure other
sample components. The purpose of the SA is to monitor method
performance with each sample.
3.3 LABORATORY DUPLICATES (LD1 AND LD2) — Two aliquots of the same
sample taken in the analytical laboratory and analyzed separately
with identical procedures. Analyses of LD1 and LD2 indicate the
precision associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures.
3.4 FIELD DUPLICATES (FD1 AND FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
515.2-3
-------
with sample collection, preservation and storage, as well as with
laboratory procedures.
3.5 LABORATORY REAGENT BLANK (LRB) — An aliquot of reagent water or
other blank matrix that is treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents, internal
standards, and surrogates that are used with other samples. The LRB
is used to determine if method analytes or other interferences are
present in the laboratory environment, the reagents, or the appara-
tus.
3.6 FIELD REAGENT BLANK (FRB) — An aliquot of reagent water or other
blank matrix that is placed in a sample container in the laboratory
and treated as a sample in all respects, including shipment to the
sampling site, exposure to sampling site conditions, storage,
preservation and all analytical procedures. The purpose of the FRB
is to 'determine if method analytes or other interferences are
present in the field environment.
3.7 INSTRUMENT PERFORMANCE CHECK SOLUTION (IPC) — A solution of one or
more method analytes, surrogates, internal standards, or other test
substances used to evaluate the performance of the instrument system
with respect to a defined set of criteria.
3.8 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water or
other blank matrix to which known quantities of the method analytes
are added in the laboratory. The LFB is analyzed exactly like a
sample, and its purpose is to determine whether the methodology is
in control, and whether the laboratory is capable of making accurate
and precise measurements.
3.9 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an envi-
ronmental sample to which known quantities of the method analytes
are added in the laboratory. The LFM is analyzed exactly like a
sample, and its purpose is to determine whether the sample matrix
contributes bias to the analytical results. The background concen-
trations of the analytes in the sample matrix must be determined in
a separate aliquot, and the measured values in the LFM corrected for
background concentrations. >
3.10 STOCK STANDARD SOLUTION (SSS) — A concentrated solution containing
one or more method analytes prepared in the laboratory using
assayed reference materials or purchased from a reputable commercial
source.
3.11 PRIMARY DILUTION STANDARD SOLUTION (PDS) — A solution of several
analytes prepared in the laboratory from stock standard solutions,
and diluted as needed to prepare calibration solutions and other
needed analyte solutions.
3.12 CALIBRATION STANDARD (CAL) — A solution prepared from the primary
dilution standard solution or stock standard solutions and the
515.2-4
-------
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analvte
concentration. • anaiyue
3.13 QUALITY CONTROL SAMPLE (QCS) - A solution of method analytes of
known concentrations which is used to fortify an aliquot of LRB or
sample matrix. The QCS is obtained from a source external to the
laboratory and different from the source of calibration standards.
it is used to check laboratory performance with externally prepared
test materials.
3.14 PROCEDURAL STANDARD CALIBRATION - A calibration method where
aqueous calibration standards are prepared and processed (e q
purged extracted, and/or derivatized) in exactly the same manner as
a sample. All steps in the process from addition of samplinq
preservatives through instrumental analyses are included in the
calibration. Using procedural standard calibration compensates for
any inefficiencies in the processing procedure.
4. INTERFERENCES
4.1 Method interferences may be caused by contaminants in solvents
reagents, glassware and other sample processing apparatus that'lead
to discrete artifacts or elevated baselines in gas chromatograms
All reagents and apparatus must be routinely demonstrated to be free
from interferences under analytical conditions by analyzing labora-
tory reagent blanks as described in Sect. 9.2.
4.1.1 Glassware must be scrupulously cleaned. (1) Clean all glass-
ware as soon as possible after use by thoroughly rinsing with
the last solvent used in it. Follow by washing with hot
; water and detergent and thorough rinsing with dilute acid
tap and reagent water. Drain dry, and heat in an oven or'
muffle furnace at 400°C for 1 hr. Do not heat volumetric
glassware. Thermally stable materials such as PCBs might not
be eliminated by this treatment. Thorough rinsing with
acetone may be substituted for the heating. After glassware
is dry and cool, store it in a clean environment to prevent
any accumulation of dust or other contaminants. Store in-
verted or capped with aluminum foil.
4.1.2 The use of high purity reagents and solvents helps to mini-
mize interference problems. Purification of solvents by
distillation in all-glass systems may be required.
WARNING: When a solvent is purified, stabilizers and preser-
vatives added by the manufacturer are removed, thus poten- •
tially making the solvent hazardous and reducing the shelf
1 i f e.
4.2 The acid forms of the analytes are strong organic acids which react
readily with alkaline substances and can be lost during sample
preparation. Glassware and glass wool must be acid-rinsed with 1 N
515.2-5
-------
hydrochloric acid and the sodium sulfate must be acidified with
sulfuric acid prior to use to avoid analyte losses due to adsorp-
tion.
4.3 Organic acids and phenols, especially chlorinated compounds, cause
the most direct interference with the determination. Alkaline
hydrolysis and subsequent extraction of the basic sample removes
many chlorinated hydrocarbons and phthalate esters that might
otherwise interfere with the electron capture analysis.
4.4 Interferences by phthalate esters can pose a major problem in pesti-
cide analysis when using the ECD. Phthalates generally appear in
the chromatogram as large peaks. Common flexible plastics contain
varying amounts of phthalates,'that are easily extracted or leached
during laboratory operations. Cross-contamination of clean glass-
ware routinely occurs when plastics are handled during extraction
steps, especially when solvent-wetted surfaces are handled. Inter-
ferences from phthalates can best be minimized by avoiding the use
of plastics in the laboratory. Exhaustive purification of reagents
and glassware may be required to eliminate background phthalate
contamination. (2,3)
4.5 Interfering contamination may occur when a sample containing low
concentrations of analytes is analyzed immediately following a
sample containing relatively high concentrations of analytes.
Between-sample rinsing of the sample syringe and associated equip-
ment with methyl-tert-butyl-ether (MTBE) can minimize sample cross-
contamination. After analysis of a sample containing high concen-
trations of analytes, one or more injections of MTBE should be made
to ensure that accurate values are obtained for the next sample.
4 6 Matrix interferences may be caused by contaminants that are coex-
tracted from the sample. Also, note that all analytes listed in the
Scope and Application Section are not resolved from each other on
any one column, i.e., one analyte of interest may interfere with
another analyte of interest. The extent of matrix interferences
will vary considerably from source to source, depending upon the
water sampled. The procedures in Sect. 11 can be used to overcome
many of these interferences. Analyte identifications should be
confirmed (Sect. 11.7).
4 7 Gas chromatographic background is significantly increased when TMSD
is used as the derivatizing reagent instead of the generated diazo-
methane. Although no method analyte is affected by this increased
background, the recommended surrogate, 2,4-dichloro-phenylacetic
acid, is masked by an interfering peak. This renders the surrogate
useless at 1 [ig/L or lower. Any compound found suitable when TMSD
is used is acceptable as a surrogate.
4.8 It is important that samples and working standards be contained in
the same solvent'. The solvent for working standards must be the
same as the final solvent used in sample preparation. If this is
515.2-6
-------
not the case, chromatographic comparability of standards'to sample
extracts may be affected.
5. SAFETY
5.1 The toxicity or carcinogenicity of each reagent used in this method
has not been precisely defined; however, each chemical compound must
be treated as a potential health hazard. Accordingly, exposure to
these chemicals must be reduced to the lowest possible level. The
laboratory is responsible for maintaining a current awareness file
of OSHA regulations regarding the safe handling of the chemicals
specified in this method. A reference file of material safety data
sheets should also be made available to all personnel involved in
the chemical analysis. Additional references to laboratory safety
are available and have been identified (5-7) for the information of
the analyst.
5.2 DIAZOMETHANE — A toxic carcinogen which can explode under certain
conditions. The following precautions must be followed:
5.2.1 Use the diazomethane generator behind a safety shield in a
well ventilated fume hood. Under no circumstances can the
generator be heated above 90°C, and all 'grinding surfaces
such as ground glass joints, sleeve bearings, and glass
stirrers must be avoided. Diazomethane solutions must not be
stored. Only generate enough for the immediate needs. The
diazomethane generator apparatus used in the esterification
procedure (Sect. 11.4) produces micromolar amounts of diazo-
methane in solution to minimize safety hazards. If the
procedure is followed exactly, no possibility for explosion
exists.
5.3 METHYL-TERT-BUTYL ETHER - Nanograde, redistilled in glass, if
necessary. Must be free of peroxides as indicated by EM Quant test
strips (available from Scientific Products Co., Cat. No. PI 126-8,
and other suppliers).
5.4 WARNING: When a solvent is purified, stabilizers added by the
manufacturer are removed, thus potentially making the solvent
hazardous.
6. EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.)
6.1 KONTES FILTER FUNNELS — Fisher Cat. No. 953755-0000 or equivalent.
6.2 VACUUM FLASKS — 1000 mL with glass side arm
6.3 VACUUM MANIFOLD — The manifold should be capable of holding 6-8
filter flasks in series with house vacuum. Commercial manifolds are
available from a number of suppliers, e.g., Baker, Fisher, and
Vari an.
515.2-7
-------
6.4 CULTURE TUBES (25 x 200 mm) WITH TEFLON-LINED SCREW CAPS — Fisher
Cat. No. 14-933-1C, or equivalent.
6.5 PASTEUR PIPETS — Glass disposable (5 mL)
6.6 LARGE VOLUME PIPETS — Disposable, Fisher Cat. No. 13-678-8 or
equivalent.
6.7 BALANCE — Analytical, capable of weighing to .0001 g.
6.8 pH METER — Wide range capable of accurate measurements in the pH =
1-12 range.
6.9 DIAZOMETHANE GENERATOR — See Figure 1 for a diagram of an all glass
system custom made for these validation studies. A micromolar
generator is also available from Aldrich Chemical.
6.10 ANALYTICAL CONCENTRATOR — Six or twelve positions, Organomation N-
EVAP Model No. 111-6917 or equivalent.
6.11 GAS CHROMATOGRAPHY — Analytical system complete with gas chromato-
graph equipped with ECD, split/splitless capillary injector, temper-
ature programming, differential flow control and all required acces-
sories. A data system is recommended for measuring peak areas. An
autoinjector is recommended to improve precision of analysis.
6.12 GC COLUMNS AND RECOMMENDED OPERATING CONDITIONS
6.12.1 Primary — DB-5 or equivalent, 30 m x .32 mm ID, 0.25 /im film
thickness. Injector Temp. = 200°C, Detector Temp. - 280°C,
Helium linear Velocity is 30 cm/sec at 200°C and 10 psi, 2 /*L
splitless injection with purge on 3 min. Program: Hold at
60°C 1 min.;, increase to 260°C at 5°C/min. and hold 5 min.
6.12.2 Confirmation — DB-1701 or equivalent, 30 m x .32 mm ID, 0.25
im film thickness. Injector Temp. = 200 °C, Detector Temp. =
280°C, Helium linear velocity is 30 cm/sec at 200°C and 10
psi, 2 ML splitless injection with purge on 3 min. Program:
Hold at 60°C 1 min., increase to 260°C at 5°C/min. and hold 5
min. '•
6.13 GLASS WOOL — Acid washed with IN Htl and heated at 450°C for 4 hr.
6.14 SHORT RANGE pH PAPER (pH=0-3).
6.15 VOLUMETRIC FLASKS -- 50 mL, 100 mL, and 250 mL
6.16 MICROSYRINGES — 25 fil, 50 p.L, 100 /tL, 250 ML, 500 /d- '
6.17 AMBER BOTTLES — 15 mL, with Teflonplined screw caps
6.18 GRADUATED CYLINDER — 250 mL
515.2-8
-------
6.19 SEPARATORY FUNNEL — 500 ml
6.20 GRADUATED CENTRIFUGE TUBES - 15 mL or 10 mL Kuderna Danish Concen-
trator tubes
7. REAGENTS AND STANDARDS
7.1 EXTRACTION DISKS, 47 mm — Resin based polystyrenedivinylbenzene
7.2 REAGENT WATER — Reagent water is defined as a water in which an
interference is not observed at the MDL of each analyte of interest.
7.2.1 A Mi 11ipore Super-Q water system or its equivalent may be
used to generate deionized reagent water. Distilled water
that has been passed through granular charcoal may also be
suitable.
7.2.2 Test reagent water each day it is used by analyzing according
to Sect. 11.
7.3 METHANOL — Pesticide quality or equivalent.
7.4 METHYL-TERT-BUTYL ETHER (MTBE) - Nanograde, redistilled in glass if
necessary. Ether must be demonstrated to be free of peroxides One
test kit (EM Quant Test Strips), is available from EM Science/
Gibbstown, NJ. Procedures for removing peroxides from the ether are
provided with the test strips. Ethers must be periodically tested
(at least monthly) for peroxide formation during use. Any reliable
test kit may be used.
7.5 SODIUM SULFATE - (ACS) GRANULAR, ANHYDROUS - Heat in a shallow
tray at 400 C for a minimum of 4 hr to remove phthalates and other
interfering organic substances. Alternatively, extract with methy-
lene chloride in a Soxhlet apparatus for 48 hr. After cleaning
store in a glass (not plastic) bottle.
7.5.1 Sodium sulfate drying tubes — Plug the bottom of a large
volume disposable pipet with a minimum amount of acidified
glass wool (Supelco Cat. No. 20383 or equivalent). Fill the
pipet halfway (3 g) with acidified sodium sulfate (See Sect.
7.6 SULFURIC ACID — Reagent grade.
7.6.1 Sulfuric acid, 12 N -- Slowly add 335 mL concentrated sulfu-
ric acid to 665 mL of reagent water.
7.7 SODIUM HYDROXIDE —.ACS reagent grade or equivalent.
7.7.1 Sodium hydroxide IN — Dissolve 4.0 g reagent grade sodium
hydroxide in reagent water and dilute to 100 mL in volumetric
flasks.
515.2-9
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7.7.2 Sodium hydroxide 6N
i '
7.8 ETHYL ETHER, UNPRESERVED — Nanograde, redistilled in glass if
necessary. Must be free of peroxides as indicated by EM Quant test
strips (available from Scientific Products Co., Cat. No. PI126-8,
and other suppliers). Procedures recommended for removal of per-
oxides are provided with the test strips.
7.9 ACIDIFIED SODIUM SULFATE — Cover 500 g sodium sulfate (Sect. 7.5)
with ethyl ether (Sect. 7.8). While agitating vigorously, add
dropwise approximately 0.7 ml concentrated sulfuric acid. Remove
the ethyl ether overnight under vacuum and store the sodium sulfate
in a 100°C oven. ]
7.10 CARBITOL, ACS GRADE — Available from Aldrich Chemical.
7.11 DIAZALD, ACS GRADE -- Available from Aldrich Chemical.
7.12 DIAZALD SOLUTION — Prepare a solution containing 10 g Diazald in
100 mL of a 50:50 by volume mixture of ethyl ether and carbitol.
This solution is stable for 1-month or longer when stored at 4°C in
an amber bottle with a Teflon-lined screw cap.
7.13 TRIMETHYLSILYLDIAZOMETHANE (TMSD) — Available from Aldrich Chemical
Co. as a 2 molar solution in hexane. TMSD is stable during storage
in this solution. t
7.14 4,4'-DIBROMOOCTAFLUOROBIPHENYL (DBOB) — 99% purity, for use as
internal standard.
7.15 2,4-DICHLOROPHENYLACETIC ACID (DCAA) — 99% purity, for use as
surrogate standard.
7.16 POTASSIUM HYDROXIDE — ACS reagent grade or equivalent.
7.16.1 Potassium hydroxide solution, 37% — Using extreme caution,
dissolve 37 g reagent grade potassium hydroxide in reagent
water and dilute to 100 mL.
7.17 STOCK STANDARD SOLUTIONS (1.00-2.00 /ig///L) — Stock standard solu-
tions may be purchased as certified solutions or prepared from pure
standard materials using the following procedure:
7.17.1 Prepare stock standard solutions by accurately weighing
approximately 0.0100-0.0200[g of pure material. Dissolve the
material in methanol and dilu-te to volume in a 10-mL volu-
metric flask. Larger volumes may be used at the convenience
of the analyst. If compound purity is certified at 96% or
greater, the weight may be Used without correction to calcu-
late the concentration of the stock standard. Commercially
prepared stock standards may be used at any concentration if
515.2-10
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they are certified by the manufacturer or by an independent
source.
7.17.2 Transfer the stock standard solutions into 15-mL TFE-fluoro-
carbon-sealed screw cap amber vials. Store at 4°C or less
when not in use.
7.17.3 Stock standard solutions should be replaced after 2 months or
sooner if comparison with laboratory fortified blanks, or QC
samples indicate a problem.
7.17.4 Primary Dilution Standards — Prepare two sets of standards
according to the sets labeled A and B in Table 1. For each
set, add approximately 25 ml of methanol to a 50 ml volumet-
ric flask. Add aliquots of each stock standard in the range
of approximately 20 to 400 pi and dilute to volume with
methanol. Individual analyte concentrations will then be in
the range of 0.4 to 8 jug/mL (for a 1.0 mg/mL stock). The
minimum concentration would be appropriate for an analyte
with strong electron capture detector (ECD) response, e.g.
pentachlorophenol. The maximum concentration is for an
analyte with weak response, e.g., 2,4-DB. The concentrations
given in Table 2 reflect the relative volumes of stock stan-
dards used for the primary dilution standards used in gener-
ating the method validation data. Use these relative values
to determine the aliquot volumes of individual stock stan-
dards above.
i
7.18 INTERNAL STANDARD SOLUTION — Prepare a stock internal standard
solution by accurately weighing approximately 0.050 g of pure DBOB.
Dissolve the DBOB in methanol and dilute to volume in a 10-mL
volumetric flask. Transfer the DBOB solution to a TFE-fluorocarbon-
sealed screw cap bottle and store at room temperature. Prepare a
primary dilution standard at approximately 1.00 jug/mL by the addi-
tion of 20 Hi of the stock standard to 100 mL of methanol. Addition
of 100 nl of the primary dilution standard solution to the final 5
mL of sample extract (Sect. 11) results in a final internal standard
concentration of 0.020, Mg/mL. Solution should be replaced when
ongoing QC (Sect. 9) indicates a problem. Note that DBOB has' been
shown to be an effective internal standard for the method analytes,
but other compounds may be used if the QC requirements in Sect. 9
are met.
7.19 SURROGATE ANALYTE SOLUTION — Prepare a surrogate analyte stock
standard solution by accurately weighing approximately 0.050 g of
pure DCAA. Dissolve the DCAA in methanol and dilute to volume in a
10-mL volumetric flask. Transfer the surrogate analyte solution to
a TFE-fluorocarbon-sealed screw cap bottle and store at room temper-
ature. Prepare a primary dilution standard at approximately 2.0
Mg/mL by addition of 40 /*L at the stock standard to 100 mL of
methanol.. Addition of 250 fil of the surrogate analyte solution to a
250-mL sample prior to extraction results in a surrogate concentra-
515.2-11
-------
tion in the sample of 2 fig/I and, assuming quantitative recovery of
DCAA, a surrogate analyte concentration in the final 5 ml extract of
0 1 ug/mL. The surrogate standard solution should be replaced when
ongoing QC (Sect. 9) indicates a problem. DCAA has been shown to be
an effective surrogate standard for the method analytes, but other
compounds may be used if the QC requirements in Sect. 9 are met.
7 20 INSTRUMENT PERFORMANCE CHECK SOLUTION — Prepare a diluted dinoseb
solution by adding 10 nl of the 1.0 [ig/nl dinoseb stock solution to
the MTBE and diluting to volume in a 10-mL volumetric flask. To
prepare the check solution, add 40 ML of the diluted dinoseb solu-
tion 16 U.L of the 4-nitrophenol stock solution, 6 /zL of the 3,5-
'dichiorobenzoic acid stock solution, 50 /iL of the surrogate standard
solution 25 pi of the internal standard solution, and 250 ML of
methanol to a 5-mL volumetric flask and dilute to volume with MTBE.
Methyl ate sample as described in Sect. 11.4. Dilute the sample to
10 ml in MTBE. Transfer to a TFE-fluorocarbon-sealed screw cap
bottle and store at room temperature. Solution should be replaced
when ongoing QC (Sect. 9) indicates a problem.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8 1 Grab samples should be collected in 1-L amber glass containers.
Conventional sampling practices (7) should be followed; however, the
bottle must not be prerinsed with sample before collection.
8.2 SAMPLE PRESERVATION AND STORAGE ,
821 If residual chlorine is present, add 80 mg of sodium thiosul-
fate (or 50 mg of sodium sulfite) per liter of sample to the
sample bottle prior to collecting the sample. Demonstration
data in Section 17 of this method was obtained using sodium
thiosulfate.
822 After the sample is collected in the bottle containing the
dechlorinating agent, seal the bottle and mix to dissolve the
thiosulfate.
8.2.3 Add hydrochloric acid (diluted 1:1 in reagent water) to the
sample at the sampling site in amounts to produce a sample pH
< 2. Short range (0-3) pH paper (Sect. 6.14) may be used to
monitor the pH. Note: Do not attempt to mix sodium thiosul-
fate and HC1 in the sample bottle prior to sample collection.
824 The samples must be iced or refrigerated at 4°C away from
light from the time of collection until extraction. Preser-
vation study results indicate that the sample analytes (mea-
sured as total acid), except 5-hydroxy-dicamba, are stable in
water for 14 days when stored under these conditions (Tables
8 and 9). The concentration of 5-hydroxydicamba is seriously
degraded over 14 days in a biologically active matrix. How-
ever, analyte stability will very likely be affected by the
515.2-12
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matrix; therefore, the analyst should verify that the preser-
vation technique is applicable to the samples under study.
8.3 EXTRACT STORAGE
8.3.1 Extracts should be stored at 4°C or less away from light.
Preservation study results indicate that most analytes are
stable for 14 days (Tables 8 and 9); however, the analyst
should verify appropriate extract holding times applicable to
the samples under study.
9. QUALITY CONTROL
9.1 Minimum QC requirements are initial demonstration of laboratory
capability, determination of surrogate compound recoveries in each
sample and blank, monitoring internal standard peak area or height
in each sample and blank, analysis of laboratory reagent blanks,
laboratory fortified matrices, laboratory fortified blanks, and QC
samples. A MDL for each analyte must also be determined. .
9,2 LABORATORY REAGENT'BLANKS (LRB) ~ Before processing any samples,
the analyst must demonstrate that all glassware and reagent inter-
ferences are under control. Each time a set of samples is extracted
or reagents are changed, a LRB must be analyzed. If within the
retention, time window of any analyte the LRB produces a.peak that
would prevent the determination of that analyte, determine the
source of contamination and eliminate the interference before
processing samples.
9.3 INITIAL DEMONSTRATION OF CAPABILITY
9.3.1 Select a representative fortified concentration (about 10 to
20 times MDL, or a mid-point in the calibration range - see
Table 4) for each analyte. Prepare a primary dilution
standard containing each analyte at 1000 times selected
concentration. With a syringe, add 250 /iL of the concen-
trate to each of four to seven.250 mL aliquots of reagent
water, and analyze each aliquot according to procedures
beginning in Sect. 11.
9.3.2 For each analyte the recovery value for all of these samples
must fall in the range of ± 40% of the fortified concentra-
tion. The RSD of the measurements must be 30% or less. For
compounds failing this criteria, this procedure must be
repeated using fresh samples until satisfactory performance
has been demonstrated for all analytes.
9.3.3 For each analyte, determine the MDL. Prepare a minimum of 7
LFBs at a low concentration. Fortification concentration in
Table 2 may be used as a guide, or use calibration data
obtained in Section 10 to estimate a concentration for each
analyte that will produce a peak with a 3-5 times signal to
515.2-13
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noise response. Extract and analyze each replicate accord-
ing to Sections 11 and 12. It is recommended that these
LFBs be prepared and analyzed over a period of several days,
so that day to day variations are reflected in the precision
measurement. Calculate mean recovery and standard deviation
for each analyte. Use the equation given in Section 13 to
calculate the MDL.
9.3.4 The initial demonstration bf capability is used primarily to
preclude a laboratory from analyzing unknown samples via a
new, unfamiliar method prior to obtaining some experience
with it. As laboratory personnel gain experience with this
method the quality of data should improve beyond those
required here.
9.4 The analyst is permitted to modify GC columns, GC conditions,
concentration techniques (i.e., evaporation techniques), internal
standard or surrogate compounds. Each time such method modifica-
tions are made, the analyst must repeat the procedures in Sect. 9.3.
9.5 ASSESSING SURROGATE RECOVERY
9.5.1 When surrogate recovery from a sample or a blank is <60% or
> 140%, check calculations to locate possible errors, forti-
fying solutions for degradation, contamination, and instru-
ment performance. If those steps do not reveal the cause of
the problem, reanalyze theiextract.
9.5.2 If a blank extract reanalysis fails the 60-140% recovery
criteria, the problem must be identified and corrected
before continuing.
9.5.3 If sample extract reanalysis meets the surrogate recovery
'criteria, report only data for the reanalyzed extract. If
sample extract continues to fail the recovery criteria,
report all data for that sample as suspect.
9.6 ASSESSING THE INTERNAL STANDARD
9.6.1 When using the internal standard (IS) calibration procedure,
the analyst must monitor the IS response (peak area or peak
height) of all samples during each analysis day. The IS
response for any sample chromatogram should not deviate from
the daily calibration check standard IS response by more
than 30%.
9.6.2 If >30% deviation occurs with an individual extract, opti-
mize instrument performance and inject a second aliquot of
that extract.
515.2-14
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9.6.2.1 If the reinjected aliquot produces an acceptable
internal standard response, report results for
that aliquot.
9.6.2.2 If a deviation of greater than 30% is obtained for
the reinjected extract, analysis of the samples
should be repeated beginning with Sect. 11, pro-
vided the sample is still available. Otherwise,
report results obtained from the reinjected ex-
tract, but annotate as suspect.
9.6.3 If consecutive samples fail the IS response acceptance
criteria, immediately analyze a medium calibration standard.
9.6.3.1 If the standard provides a response within 20% of
the .predicted value, then follow procedures item-
ized in Sect. 9.6.2 for each sample failing the IS
response criterion.
9.6.3.2 If the check standard provides a response which
deviates more than 20% of the predicted value,
then the analyst must recalibrate as specified in
/Sect. 10.
9.7 ASSESSING LABORATORY PERFORMANCE — LABORATORY FORTIFIED BLANK
9.7.1 The laboratory must analyze at least one laboratory forti-
fied blank (LFB) sample with every 20 samples or one per
sample set (all samples extracted within a 24-hr period)
whichever is greater. The concentration of each analyte in
the LFB should be approximately the same as in Sect. 9.3.1.
Calculate percent recovery (X,-). If the recovery of any
analyte falls outside the control limits (See Sect. 9.7.2),
..• that analyte is judged out of control, and the source of the
problem should be identified and resolved before continuing
analyses.
9.7.2 Until sufficient data become available, usually a minimum of
results from 20 to 30 analyses, each laboratory should
assess laboratory performance against the control limits in
Sect. 9.3.2 that are derived from the data in Table 2. When
sufficient internal performance data become available, ,
develop control limits from the mean percent recovery (X)
and standard deviation (S) of the percent recovery. These
data are used to establish upper and lower control limits as
follows:
UPPER CONTROL LIMIT = X + 3S
LOWER CONTROL LIMIT = X - 3S
After each five to ten new recovery measurements, new con-
trol limits should be calculated using only the most recent
515.2-15
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20-30 data points. These calculated control limits should
not exceed those established in Sect. 9.3.2.
9.7.3 At least quarterly, analyze a QCS (Sect. 3.13) from an
outside source.
9.8 ASSESSING ANALYTE RECOVERY - LABORATORY FORTIFIED SAMPLE MATRIX
9.8.1 Each laboratory must analyze a LFM for 10% of the samples or
one sample concentration per set, whichever is greater. The
concentration should not be less then the background concen-
tration of the sample selected for fortification. Ideally,
the concentration should be the same as that used for the
laboratory fortified blank (Sect. 9.7). Over time, samples
from all routine sample sources should be fortified.
9.8.2 Calculate the percent recovery, P, of the concentration for
each analyte, after correcting the measured concentration,
X, from the fortified sample for the background concentra-
tion, b, measured in the unfortified sample.
P = 100 (X - b) / fortified concentration,
and compare these values to. control limits appropriate for
reagent water data collected in the same fashion. Accep-
tance criteria are the same as those in Section 9.7 for
LFBs.
9.8.3 If the recovery of any such analyte falls outside the desig-
nated range, and the laboratory performance for that analyte
is shown to be in control (Sect. 9.7), the recovery problem
encountered with the fortified sample is judged to be matrix
related, not system related. The result for that analyte in
the unfortified sample is labeled suspect/matrix to inform
the data user that the results are suspect due to matrix
effects.
9.9 ASSESSING INSTRUMENT SYSTEM/INSTRUMENT PERFORMANCE CHECK (IPC)
SAMPLE — Instrument performance should be monitored on a daily
basis by analysis of the IPC sample. The IPC sample contains
compounds designed to monitor instrument sensitivity, column
performance (primary column) and ehromatographic performance. IPC
sample components and performance criteria are listed in Table 11.
The sensitivity requirements are set based on the MDLs published in
this method. If the laboratory MDLs differ from those demonstrated
here, the amount of dinoseb in the IPC sample should be adjusted
accordingly.
9.10 The laboratory may adopt additional QC practices for use with this
method. The specific practices that are most productive depend
upon the needs of the laboratory and the nature of the samples.
For example, field or laboratory duplicates may be analyzed to
assess the precision of the envirbnmental measurements or field
515.2-16
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reagent blanks may be used to assess contamination of samples under
site conditions, transportation, and storage.
10. CALIBRATION AND STANDARDIZATION
10.1 Establish GC operating parameters equivalent to those indicated in
Sect. 6.12. 'This calibration procedure employs procedural calibra-
tion standards, i.e., fortified aqueous standards which are pro-
cessed through the method (Sect. 11). The GC system is calibrated
by means of the internal standard technique (Sect. 10.2). NOTE:
Calibration standard solutions must be prepared such that no unre-
solved analytes are mixed together (See Table 1).
10.2 INTERNAL STANDARD CALIBRATION PROCEDURE — To use this approach, the
analyst must select one or more internal standards compatible in
analytical behavior to the compounds of interest. The analyst must
further demonstrate that the measurement of the internal standard is
not affected by method or matrix interferences. DBOB (Sect. 7.14)
has been identified as a suitable internal standard.
10.2.1 Prepare aqueous calibration standards at a minimum of three
(five are recommended) concentration levels for each method
analyte as follows: for each concentration, fill a 250-mL
volumetric flask with 240 mL of reagent water at pH 1 and
containing 50 g of dissolved sodium sulfate. Add an appro-
priate aliquot of the primary dilution standard (Sect. 7.17-
.4) and dilute to 250 mL with the same reagent water. Guid-
ance on the number of standards is as follows: A minimum of
three calibration standards are required to calibrate a range
of a factor of 20 in concentration. For a factor of 50 use
at least four standards, and for a factor of 100 at least .-
five standards. The lowest standard should represent analyte
concentrations near, but above, their respective MDLs. The
remaining standards should bracket the analyte concentrations
expected in the sample extracts, or should define the working
range of the detector. Process each aqueous calibration
sample through the analytical procedure beginning with Sect.
11.1.2. The internal standard is added to the final 5 mL
extract as specified in Sect. 11.4.3 or 11.5.9.
10.2.2 Analyze each calibration standard according to the procedure
beginning in Sect. 11.1.2. Tabulate response (peak height or
area) against concentration for each compound and internal
standard. Calculate the response factor (RF) for each anal-
.yte and surrogate using Equation 1.
RF =
(As) (C,.)
(Ai.) (C.)
Equation 1
515.2-17
-------
where:
As = Response for the analyte to be measured.
Ais = Response for the internal standard.
Cis = Concentration of the internal standard (/zg/L).
Cs = Concentration of the analyte to be measured (/jg/L).
10.2.3 If the RF value over the working range is constant (30% RSD
or less) the average RF can be used for calculations. Alter-
natively, the results can be used to plot a calibration curve
of response ratios (A /Ais) vs. Cs. A data station may be
used to collect the cnromatographic data, calculate response
factors and generate linear or second order regression
curves.
10.2.4 The working calibration curve or RF must be verified on each
working shift (not to exceed 12 hours) by the measurement of
one or more calibration standards. It is highly recommended
that a calibration verification be performed at the beginning
and at the end of every extended period of instrument opera-
tion so that field sample extracts are bracketed by calibra-
tion standards. It is also recommended that more that one
standard concentration be analyzed.so that the calibration is
verified at more than one point. New calibration standards
need not be derivatized each day. The same standard extract
can be used up to 14 days. If the response for any analyte
varies from the predicted response by more than +30%, the
test must be repeated using a fresh calibration standard. If
the repetition also fails; a new calibration curve must be
generated for that analyte using freshly prepared standards.
For those analytes that failed the calibration verification,
results from field samples analyzed since the last passing
calibration should be considered suspect. Reanalyze sample
extracts for these analytes after acceptable calibration is
restored.
10.2.5 Verify calibration standards periodically, at least quarterly
is recommended, by analyzing a standard prepared from refer-
ence material obtained from an independent source. Results
from these analyses must be within the limits used to rou-
tinely check calibration.
11. PROCEDURE
11.1 MANUAL HYDROLYSIS AND SEPARATION OF INTERFERENCES
11.1.1 Remove the sample bottles from cold storage and allow them to
equilibrate to room temperature. Acidify and add sodium
thiosulfate to LFBs, LRBs and QCSs as specified in Sect. 8.
11.1.2 Measure a 250-mL aliquot of each sample with a 250-tnL gradu-
ated cylinder and pour into a 500-mL separatory funnel. Add
250 /iL of the surrogate primary dilution standard (Sect.
515.2-18
-------
7.19) to each 250-mL sample. The surrogate will be at a
concentration of 2 /ig/L. Dissolve 50 g sodium sulfate in the
sample.
11.1.3 Add 4 ml of 6 N NaOH to each sample, seal, and shake. Check
the pH of the sample with pH paper or a pH meter; if the
sample does not have a pH greater than or equal to 12, adjust
the pH by adding more 6 N NaOH. Let the sample sit at room
temperature for 1 hr, shaking the separatory funnel and
contents periodically. Note: Since many of the herbicides
contained in this method are applied as a variety of esters
and salts, it is vital to hydrolyze them to the parent acid
prior to extraction. This step must be included in the
analysis of all extracted field samples, LRBs, LFBs, LFMs,
and QCS.
11.1.4 Add 15 ml methylene chloride to the graduated cylinder to
rinse the walls, transfer the methylene chloride to the
separatory funnel and extract the sample by vigorously shak-
ing the funnel for 2 min with periodic venting to release
excess pressure. Allow the organic layer to separate from
the water phase for a minimum of 10 min. If the emulsion
interface between layers is more than one-third the volume of
the solvent layer, the analyst must employ mechanical tech-
niques to complete the phase separation. The optimum tech-
nique depends upon the sample, but may include stirring,
filtration through glass wool, centrifugation, or other
physical methods. Discard the methylene chloride phase
(Sect.14,15).
11.1.5 Add a second 15-mL volume of methylene chloride to the separ-
atory funnel and repeat the extraction procedure a second
time, discarding the methylene chloride layer. Perform a
third extraction in the same manner.
11.1.6 Drain the contents of the separatory funnel into a 500-mL
beaker. Adjust the pH to 1.0 ± 0.1 by the dropwise addition
of concentrated sulfuric acid with constant stirring. Monitor
the pH with a pH meter (Sect. 6.8) or short range (0-3) pH
paper (Sect. 6.14).
11.2 SAMPLE EXTRACTION
11.2.1 Vacuum Manifold — Assemble a manifold (Sect. 6.3) consisting
of 6-8 vacuum flasks with filter funnels (Sect. 6.1,6.2).
Individual vacuum control, on-off and vacuum release valves
and vacuum gauges are desirable. Place the 47 mm extraction
disks (Sect. 7.1) on the filter frits.
11.2.2 Add 20 mL of 10% by volume of methanol in MTBE to the top of
each disk without vacuum and allow the solvent to remain for
2 min. Turn on full vacuum and draw the solvent through the
disks, followed by room air for 5 min.
515.2-19
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11.2.3 Adjust the vacuum to approximately 5 in. (mercury) and add
the following in series to the filter funnel (a) 20 ml
methanol (b) 20 mL reagent wa;ter (c) sample. Do not allow
the disk to dry between steps and maintain the vacuum at 5
in.
11.2.4 After all the sample has passed through the disk, apply
maximum vacuum and draw room air through the disks for 20
min.
11.2.5 Place the culture tubes (Sect. 6.4) in the vacuum tubes to
collect the eluates. Elute t\\e disks with two each 2-mL
aliquots of 10% methanol in MTBE. Allow each aliquot to
remain on the disk for one mih before applying vacuum.
11.2.6 Rinse each 500-mL beaker (Sect.ll;1.6) with 4 mL of pure MTBE
and elute the disk with this solvent as in Sect. 11.2.5.
11.2.7 Remove the culture tubes and cap.
j'
11.3 EXTRACT PREPARATION ;
11.3.1 Pre-rinse the drying tubes (Sect. 7.5.1) with 2 mL of MTBE.
11.3.2 Remove the entire extract with a 5-mL pipet and drain the
lower aqueous layer back into the culture tube. Add the
organic layer to the sodium sulfate drying tube (Sect.
7.5.1). Maintain liquid in the drying tube between this and
subsequent steps. Collect the dried extract in a 15-mL
graduated centrifuge tube or a 10-mL Kuderna-Danish tube.
11.3.3 Rinse the culture tube with an additional 1 mL of MTBE and
repeat Sect. 11.3.2. :
11.3.4 Repeat step Sect. 11.3.3 and finally add a 1-mL aliquot of
MTBE to the drying tube before it empties. The final volume
should be 6-9 mL. In this form the extract is esterified as
described below.
11.4 EXTRACT ESTERIFICATION WITH DIAZOMETjHANE — See Section 11.5 for
alternative procedure. j
11.4.1 Assemble the diazomethane generator (Figure 1) in a hood.
11.4.2 Add 5 mL of ethyl ether to Tube 1. Add 4 mL of Diazald
solution (Sect. 7.12) and 3 mL of 37% KOH solution (Sect.
7.16.1) to the reaction tube 2. Immediately place the exit
tube into the collection tube containing the sample extract.
Apply nitrogen flow (10 mL/min) to bubble diazo-methane
through the extract. Each charge of the generator should be
sufficient to esterify four samples. The appearance of a
persistent yellow color is an indication that esterification
is complete. The first sample should require 30 sec to 1 min
515.2-20
-------
and each subsequent sample somewhat longer. The final sample
may require 2-3 mi IT.
11.4.3 Cap each collection tube and allow to remain stored at room
temperature in a hood for 30 min. No significant fading of
the yellow color should occur during this period. Fortify
each sample with 100 juL of the internal standard primary
dilution solution (Sect. 7.18) and reduce the volume to 5.0
ml with the analytical concentrator (Sect. 6.10), a stream of
dry nitrogen, or an equivalent concentration technique.
NOTE: The excess diazomethane is volatilized from the
extract during the concentration procedure.
11.4.4 Cap the tubes and store in a refrigerator if further process-
ing will not be performed immediately. Analyze by GC-ECD.
11.5 EXTRACT ESTERIFICATION WITH TRIMETHYLSILYLDIAZOMETHANE (TMSD) --
•'Alternative .procedure. It should be noted that the gas
chromatographic background is significantly increased when TMSD is'
used as the derivatizing reagent instead of the generated
diazomethane. Although no method analyte is affected by this
increased background, the recommended surrogate, 2,4-dichloro-
phenylacetic acid, is masked by an interfering peak. This renders
the surrogate useless at 1 jiig/L or lower. Any compound found
suitable when TMSD is used is acceptable as a surrogate.
11.5.1 Carry out the hydrolysis, clean-up, and extraction of the
method analytes as described up to Sect. 11.2.4.
11.5.2 Elute the herbicides from the disk by passing two 2 ml
aliquots of methyl tertiary butyl ether (MTBE) through the
disk into the collection tube. Rinse the sample container
with 4 ml of MTBE and pass it through the disk into the tube.
11.5.3 Transfer the MTBE extract from the collection tube into an
anhydrous sodium sulfate drying tube which has been pre-
wetted with 1 ml MTBE. Be sure to discard any water layer.
11.5.4 Before the extract passes completely through the sodium
sulfate, add an additional 2 ml of MTBE as a rinse.
11.5.5 Concentrate the dried extract to approximately 4 ml. Add
methanol (approx. 1 ml) to the extract to yield a 20% (v/v)
methanol in MTBE solution. Adjust the volume to 5 ml with
MTBE. (TMSD produces the most efficient methylation of the
herbicides in a 20% methanol, 80% MTBE solution.)
11.5.6 Add 50 fil of the 2 M TMSD solution to each 5 mL sample
extract.
11.5.7 Place the tube containing the extract into a heating block at
50°C and heat the extract for 1 hour.
515.2-21
-------
11.5.8 Allow the extract to cool to room temperature, then add 100
IJ.L of 2 M acetic acid in mei;hanol to react with any excess
TMSD.
11.5.9 Fortify the extract with 100 ill of the internal standard
solution (See Sect. 7.18) to yield a concentration of 0.020
tig/ml.
11.2.10 Proceed with the identification and measurement of the
analytes using GC/ECD according to the procedures described
in Sect 11.6.
11.6 GAS CHROMATOGRAPHY
11.6.1 Sect. 6.12 summarizes the recommended GC operating
conditions. Included in Table 1 are retention times observed
using this method. Figures 2A and 2B illustrate the
chromatographic performance of the primary column (Sect.
6.12.1) for groups A and B pf the method analytes. Other GC
columns or chromatographic Conditions, may be used if the
requirements of Sect. 9.3 are met.
11.6.2 Calibrate or verify the existing calibration daily as
described in Sect. 10.
11.6.3 Inject 2 /*L of the sample extract.
size in area units.
Record the resulting peak
11.6.4 If the response for any sample peak exceeds the working range
of the detector, dilute the extract and reanalyze. Add
additional IS, so that the ;IS amount in the extract will be
the same as in the calibration standards.
11.7 IDENTIFICATION OF ANALYTES
11.7.1 Identify a sample component by comparison of its retention
time to the retention time of a reference chromatogram. If
the retention time of an unknown compound corresponds, within
limits, to the retention time of a standard compound, then an
analyte is considered to be identified.
11.7.2 The width of the retention time window used to make identi-
fications should be based upon measurements of actual
retention time variations of standards over the course of a
day. Three times the standard deviation of a retention time
can be used to calculate a suggested window size for a
compound. However, the experience of the analyst should
weigh heavily in interpretation of chromatograms.
11.7.3 Identification requires expert judgment when sample compo-
nents are not resolved chromatographically. When GC peaks
obviously represent more than one sample component (i.e.,
broadened peak with shoulder(s) or valley between two or more
515.2-22
-------
; •-'•-. maxima, ,or any time doubt exists over the identification of a
peak in a chromatogram, appropriate alternative techniques to
help confirm peak identification need to be employed. For
example, more positive identification may be made by the use
>•:• of an alternative detector which operates on a
,, . ...-.V; chemical/physical principle different from that originally
used, e.g., mass spectrometry, or the use of a second
chromatography column. A suggested alternative column is
-,;.•• .- , described in Sect, 6.12.2. .-.-.-.
12. DATA ANALYSIS AND CALCULATIONS
12.1 Calculate analyte concentrations in the sample from the response for
the analyte using the calibration procedure described in Sect. 10.
Use.,the multi-point calibration for each analyte to make all
calculations. Do not use the daily calibration verification data to
quantitate analytes in samples.
12.2 Calculate the concentration (C) in the sample using the response
factor (RF) determined in Sect. 10.2.2 and Equation 2, or determine
sample concentration from the calibration curve-(Sect. 10.2.3).
' ' , ..-.; ' ;• CAS)(IS) . ..*
c (M9/L) = . .. Equation 2.
(Ais)(RF)(V0)
where:
As .== Response, for the analyte.to be measured.
Ajs = Response for the internal standard. • ' '.
I.s .= Amount of internal standard added to each
, extract (/jg),.- • , ,
V0 = Volume of water extracted (L).
13. METHOD PERFORMANCE
13.L All data .shown in Section 17 of this method were obtained with the
diazomethane-esterification option.
13.2 In a single laboratory, analyte recoveries from reagent water were
determined at three concentration levels, Tables 2-4. Results were
used to determine,thfi analyte MDLs (8) listed in Table 2. The
calculation, fordetermining MDL is:
where^,'?S t(n"1/1"alpha = °-99).
'^(n-i.i-aipha = o.99) = Student's t value for the 99%
confidence level with n-1 degrees of freedom
n - number of replicates
S = standard deviation,of replicate analyses.
515.2-23
-------
13.3 In a single laboratory, analyte recoveries from dechlorinated tap
water were determined at two concentrations, Tables 5 and 6. In
addition, analyte recoveries were determined at two concentrations
from an ozonated surface (river) water, Tables 7 and 8, and at one
level from a high humectant surface (reservoir) water, Table 10.
Finally, a holding study was conducted on the preserved, ozonated
surface water and recovery data are presented for day 1 and day 14
of this study, Tables 8 and 9. The ozonated surface water was
chosen as the matrix in which to study analyte stability during a
14-day holding time because it was very biologically active.
This
14. POLLUTION PREVENTION
14.1 This method utilizes liquid-solid extraction technology which
requires the use of very small quantities of organic solvents.
feature eliminates the hazards involved with the use of large
volumes of potentially harmful organic solvents needed for
conventional liquid-liquid extractions. Also, mercuric chloride, a
highly toxic and environmentally hazardous chemical, has been
replaced with hydrochloric acid as the sample preservative. These
features make this method much safer and a great deal less harmful
to the environment.
14.2 For information about pollution prevention that may be applicable to
laboratory operations, consult "Less is Better: Laboratory Chemical
Management for Waste Reduction" available from the American Chemical
Society's Department of Government Relations and Science Policy,
1155 16th Street N.W., Washington, D.C. 20036.
15. WASTE MANAGEMENT
15.1 Due to the nature of this method, there is little need for waste
management. No large volumes of solvents or hazardous chemicals are
used. The matrices of concern are finished drinking water or source
water. However, the Agency requires that laboratory waste manage-
ment practices be conducted consistent with all applicable rules and
regulations, and that laboratories protect the air, water, and land
by minimizing and controlling all releases from fume hoods and bench
operations. Also, compliance is required with any sewage discharge
permits and regulations, particularly the hazardous waste identifi-
cation rules and land disposal restrictions. For further informa-
tion on waste management, consult "The Waste Management Manual for
Laboratory Personnel," also available from the American Chemical
Society at the address in Sect. 14.2.
16. REFERENCES
1. ASTM Annual Book of Standards, Part 11, Volume 11.02, D3694-82,
"Standard Practice for Preparatioji of Sample Containers and for
Preservation," American Society for Testing and Materials,
Philadelphia, PA, p. 86, 1986.
515.2-24
-------
2' •Sln?; Committee on Chemical Safety, 3rd Edition,
7. ASTM Annual Book of Standards, Part 11, Volume 11.01, D3370-82
Standard Practice for Sampling Water," American Society for Testing
and Materials, Philadelphia, PA, p. 130, 1986. '"iing
, J.A., Foerst, D.L., McKee, G.D., Quave, S.A., and Budde,
ii!" 1426-1435 yS6S Wastewaters," Environ. Sen. Techno! . 1981,
9. 40 CFR, Part 136, Appendix B.
515.2-25
-------
17. TABLES. DIAGRAMS. FLOWCHARTS AND VALIDATION DATA
TABLE 1. RETENTION DATA
Retention Time,
Analvte Groirn3 Primarv
3,5-Dichlorobenzoic acid
2,4-Dichlorophenylacetic acid (SA)
Dicamba
Dichlorprop
2,4-D
4,4'-Dibromooctafluorobiphenyl (IS)
Pentachlorophenol
Si 1 vex
5-Hydroxydicamba
2,4,5-T
2,4-DB
Dinoseb
Bentazon
Picloram
Dacthal diacid metabolite
Acifluorfen
A ' ;
A,B
B
A
B
A,B
A
B
B ,
A '
B
A
B
B
A
B
16.72
19.78
20.18
22.53
23.13
24.26
25.03
25.82
26.28
26.57
27.95
28.03
28.70
29.93
31.02
35.62
min.D
Confirmation
18.98
22.83
23.42
25.90
27.01
26.57
27.23
29.08
30.18
30.33
31.47
33.02
33.58
35.90
34.32
40.58
a Analytes were divided into two groups during method development to
avoid chromatographic overlap.
b Columns and chromatographic conditions are described in Sect. 6.12.
515.2-26
-------
TABLE 2. SINGLE LABORATORY RECOVERY, PRECISION DATA
AND METHOD DETECTION LIMIT WITH FORTIFIED
REAGENT WATER - LEVEL 1
Analvte
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal diacid metabolite
Dicafnba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicamba
Pentachlorophenol
Picloram
2,4,5-T
2,4,5-TP
Fortified
Cone.
UQ/L
0.50
2.50
0.25
2.50
0.25
1 0.75
1.25
0.25
0.50
0.75
0.25
0.75
0.25
0.25
Mean3
Recovery
%
78
70
96
79
96
109
126
106
87
90
103
95
116
98
Relative
Std. Dev.
%
21
11
38
12
16
11
24
15
22
12
18
15
18
9
MDL
ua/L
0.25
0.63
0.28
0.72
0.13 .
0.28
1.23
0.13
0.28
0.25
0.16
0.35
0.16
0.06
a Based on the analyses of seven replicates.
515.2-27
-------
TABLE 3. SINGLE LABORATORY RECOVERY AND PRECISION DATA
FOR FORTIFIED REAGENT WATER - LEVEL 2
Anal vte .
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal diacid metabolite
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicamba
Pentachlorophenol
Picloram
2,4,5-T
2,4,5-TP
Fortified
Cone.
ua/l
0.80
4.0
0.40
4.0
0.40
I
1.20
2.00
0.40
0.80
1.20
0.40
1.20
0.40
0.40
Mean3
Recovery
%
61
81
96
90
96
109
126
76
87
90
66
68
116
105
Relative
Std. Dev.
%
27
8
38
13
16
11
24
21
22
12
26
21
18
7
a Based on the analyses of six-seven replicates.
515.2-28
-------
TABLE 4. SINGLE LABORATORY RECOVERY AND PRECISION DATA
FOR FORTIFIED REAGENT WATER - LEVEL 3
Analvte
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal diacid metabolite
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicamba
Pentachlorophenol
Picloram
2,4,5-T
2,4,5-TP
Fortified
Cone.
ua/L
2.0
10.0
1.0
10.0
1.0
3.0
5.0
1.0
2.0
3.0
1.0
3.0
1.0
1.0
Mean3
Recovery
%
59
68
90
74
60
75
62
97
63
77
69
66
64
68
Relative
-Std. Dev.
01
13
8
20
,6
10
9
18
17
10
8
11
9
15
8
a Based on the analyses of six-seven replicates.
515.2-29
-------
TABLE 5. SINGLE LABORATORY RECOVERY AND PRECISION DATA
FOR FORTIFIED, DECHLORINATED TAP WATER - LEVEL 1
Analvte
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal diacid metabolite
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicamba
Pentachl orophenol
Picloram
2,4,5-T
2,4,5-TP
Fortified
Cone.
' aa/L
0.50
2.50
0.25
2.50
0.25
0.75
1.25
0.25
0.50
0.75
0.25
i
0.75
0.25
0.25
Mean3
Recovery
%
117
96
59b
112
101
91
103
218C
134
90
91
76
118
99
Relative
Std. Dev.
%
21
12
55
15
10
14
15
37
'10
14
8
28
16
10
a Based on the analyses of six-seven replicates.
b 2,4-D background value was 0.29 /ig/L.
c Probable interference.
515.2-30
-------
TABLE 6. SINGLE LABORATORY RECOVERY AND PRECISION DATA'
FOR FORTIFIED, DECHLORINATED TAP WATER - LEVEL 2
Analvte
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal diacid metabolite
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicamba
Pentachlorophenol
Picloram
2,4,5-T
2,4,5-TP
2,4-Dichlorophenylacetic acid6
Fortified
Cone.
ua/L
2.0
10.0
1.0
10.0
1.0
3.0
5.0
1.0
2.0
3.0
1.0
3.0
1.0
1.0
1.0
Mean3
Recovery
%
150
112
90
111
118
86
111
88
121
96
96
132
108
115
120
Relative
Std. Dev.
"/
7
9
16
10
8
10
5
30
6
6
6
12
10
7
19
a Based on the analyses of six-seven replicates.
b Surrogate analyte.
515.2-31
-------
TABLE 7. SINGLE LABORATORY RECOVERY AND PRECISION DATA
FOR FORTIFIED, OZONATED SURFACE WATER - LEVEL 1
Analvte
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal diacid metabolite
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicamba
Pentachl orophenol
Picloram
2,4,5-T
2,4,5-TP
2,4-Dichlorophenylacetic acidb
Fortified
Cone.
uq/L
0.50
2.50
0.25
2.50
0.25
0.75
1.25 '
0.25
\
0.50
0.75
0.25
0.75
0.25
0.25
0.25
Mean3
Recovery
%
172
92
127
154
113
107
100
115
134
89
110
109
102
127
72
Relative
Std. Dev.
%
14
22
13
19
17
13
17
20
28
13
22
27
19
8
31
a Based on the analyses of six-seven replicates.
b Surrogate analyte.
515.2-32
-------
TABLE 8. SINGLE LABORATORY RECOVERY AND PRECISION DATA FOR FORTIFIED
OZONATED SURFACE WATER - LEVEL 2, STABILITY STUDY DAY lb '
Analvte
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal diacid metabolite
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicatnba
Pentachlorophenol
Picloram
2,4,5-T
2,4,5-TP
2,4-DichTorophenylacetic acidc
Fortified
Cone.
UQ/l
2.0
10.0
1.0
10.0
1.0
3.0
5.0
1.0
2.0
3.0
1.0
3.0
1.0
1.0
1.0
Mean3
Recovery
%
173
122
126
130
116
109
115
116
116
121
118
182
112
122
110
Relative
Std. Dev.
°/
11
7
10
7
11
9
. 11
11
9
9
10
14
9
10
26
a Based on the analyses -of six-seven replicates.
b Samples preserved at pH = 2.0.
c Surrogate analyte.
515.2-33
-------
TABLE 9. SINGLE LABORATORY RECOVERY AND PRECISION DATA FOR FORTIFIED,
OZONATED SURFACE WATER - LEVEL 2, STABILITY STUDY DAY 14b
Analvte
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal diacid metabolite
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicamba
Pentachlorophenol
Picloram
2,4,5-T
2,4,5-TP
2,4-Dichlorophenylacetic acidc
Fortified
Cone.
ULQ/l
2.0
10.0"
1.0
10.0
1.0
3.0
5.0
i
1.0
2.0
3.0
1.0 -
3.0 :
1.0
1.0
1.0 '.
Mean3
Recovery
% •
151
97
84
128
116 •
103
81
107
118
20
94
110
113
113
87
Relative
Std. Dev. ,
• %
18
9
11
10
7
9
'• ' ••'•'•. T2 '" ' :;"
11 '
7 .
;' '14 '
' -1' 7
32
8
11
... 6
a Based on the analyses of six-seven replicates.
b Samples preserved at pH = 2.0.
c Surrogate analyte.
515.2-34
-------
TABLE 10. SINGLE LABORATORY RECOVERY AND PRECISION DATA FOR
FORTIFIED, HIGH HUMIC CONTENT SURFACE WATER
Analvte
Acifluorfen
Bentazon
2,4-D
2,4-DB
Dacthal diacid metabolite
Dicamba
3,5-Dichlorobenzoic acid
Dichlorprop
Dinoseb
5-Hydroxydicamba
Pentachlorophenol
Picloram
2,4,5-T
2,4,5-TP
Fortified
Cone.
//a/I
2.0
10.0
1.0
10.0
1.0
3.0
5.0
1.0
2.0
3.0
1.0
3.0
1.0
1.0
Mean3
Recovery
%
120
87
59
80
100
76
87
110
97
82
70
124
101
80
Relative
Std. Dev.
"/
13
11
7
14
6
9
4
22
6
9
5
9
4
6
a Based on the analyses of six-seven replicates.
515.2-35
-------
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515.2^36
-------
HOW
4- f\AT JOINT WJTH 0 WHO AND CUM*
OIETHYL ETHERIEVU
f LAT XXNT WTH 0 JUNG AND CUM*
OlAZALOUVfL
KOH
FIGURE 1. DIAZOMETHANE GENERATOR
515.2-37
-------
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THIS PAGE LEFT BLANK INTENTIONALLY
515.2-40
-------
METHOD 524.2. MEASUREMENT OF PUR6EABLE ORGANIC COMPOUNDS IN WATER BY
CAPILLARY COLUMN GAS CHROMATOGRAPHY/MASS SPECTROMETRY
Revision 4.1
Edited by J.W. Munch (1995)
A. AT ford-Stevens, J.W. Eichelberger, W.L. Budde - Method 524, Rev. 1.0 (1983)
R.W. Slater, Jr. - Revision 2.0 (1986)
J.W. Eichelberger, and W.L. Budde - Revision 3.0 (1989)
J.W. Eichelberger, J.W. Munch, and T.A. Bellar - Revision 4.0 (1992)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
524.2-1
-------
METHOD 524.2
MEASUREMENT OF PURGEABLE ORGANIC COMPOUNDS IN WATER BY
CAPILLARY COLUMN GAS CHROMATOGRAPHY/MASS SPECTROMETRY
1. SCOPE AND APPLICATION
1.1 This is a general purpose method for the identification and simulta-
neous measurement of purgeable volatile organic compounds in surface
water, ground water, and drinking water in any stage of treatment
(1,2). The method is applicable to a wide range of organic com-
pounds, including the four trihalomethane disinfection by-products,
that have sufficiently high volatility and low water solubility to
be removed from water samples with purge and trap procedures. The
following compounds can be determined by this'method.
Chemical Abstract Service
Analvte Registry Number
Acetone* 67-64-1
Acrylonitrile* 107-13-1
Ally! chloride* 107-05-1
Benzene 71-43-2
Bromobenzene 108-86-1
Bromochlorom'ethane 74-97-5
Bromodichloromethane 75-27-4
Bromoform . 75-25-2
Bromomethane 74-83-9
2-Butanone* 78-93-3
n-Butylbenzene 104-5J-8
sec-Butyl benzene 135-98-8
tert-Butylbenzene 98-06-6
Carbon disulfide* 75-15-0
Carbon tetrachloride 56-23-5
Chloroacetonitrile* 107-14-2
Chlorobenzene 108-90-7
1-Chlorobutane* 109-69-3
Chlorpethane 75-00-3
Chloroform 67-66-3
Chloromethane 74-87-3
2-Chlorotoluene 95-49-8
4-Chlorotoluene 106-43-4
Dibromochloromethane 124-48-1
l,2-Dibromo-3-chloropropane 96-12-8
1,2-Dibromoethane 106-93-4
Dibromomethane ' 74-95-3
1,2-Dichlorobenzene 95-50-1
1,3-Dichlorobenzene 541-73-1
1,4-Dichlorobenzene 106-46-7
trans-l,4-Dichloro-2-butene* 110-57-6
Dichlorodifluoromethane 75-71-8
524.2-2
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1,1-Dichloroethane . 75-34-3
1,2-Dichloroethane 107-06-2
1,1-Dichloroethene 75-35-4
cis-l,2-Dichloroethene 156-59-2
trans-l,2-Dichloroethene 156-60-5
1,2-Dichloropropane 78-87-5
1,3-Dichloropropane , 142-28-9
2,2-Dichloropropane 590-20-7
1,1-Dichloropropene 563-58-6
1,1-Dichloropropanone* 513-88-2
cis-l,3-Dichloropropene 10061-01-5
trans-l,3-Dichloropropene 10061-02-6
Diethyl ether* 60-29-7
Ethyl benzene 100-41-4
Ethyl methacrylate* 97-63-2
Hexachlorobutadiene 87-68-3
Hexachloroethane* 67 72 1
2-Hexanone* 591-78-6
Isopropylbenzene 98-82-8
4-Isopropyltoluene 99-87-6
Methacrylonitrile* 126-98-7
Methylacrylate* 96-33-3
. Methylene chloride 75.09-?
Methyl iodide* 74-88-4
Methylmethacrylate* 80-62-6
4-Methyl.-2-pentanone* 108-10-1
Methyl-t-butyr ether* 1634-04-4
Naphthalene 91-20-3
Nitrobenzene* '. 98-95-3
2-Nitropropane* 7g_46_g
Pentachloroethane* 76-01-7
Propionitrile* . 107-12-0
n-Propylbenzene 103-65 1
Styrene 100-42-5
1,1,1,2-Tetrachloroethane 630-20-6
1,1,2,2-Tetrachloroethane 79-34-5
Tetrachloroethene 127-18-4
Tetrahydrofuran* 109-99-9
Toluene • inn ao ••» •
1 o i -r • i i ' • lUO-OO-J
1,2,3-Trichlorobenzene 87-61-6
1,2,4-Trichlorobenzene 120-82-1
1,1,1-Trichloroethane 71-55-6
1,1,2-Trichloroethane 79-00-5
Trichloroethene 79-01-6
Trichlorofluoromethane 75-69-4
1,2,3-Trichloropropane 96-18-4
1,2,4-Trimethylbenzene 95-63-6
1,3,5-Trimethylbenzene 108-67-8
Vinyl chloride 75_01 4
o-Xylene 95-47-6
m-Xy ene 108-38-3
P-Xylene 106-42-3
New Compound in Revision 4.0
524.2-3
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1.2 Method detection limits (MDLs) (3) are compound, instrument and
especially matrix dependent and vary from approximately 0.02 to 1.6
/zg/L. The applicable concentration range of this method is primari-
ly column and matrix dependent, and is approximately 0.02 to 200
/zg/L when a wide-bore thick-film capillary column is used. Narrow--
bore thin-film columns may have a capacity which limits the range to
about 0.02 to 20 /zg/L. Volatile water soluble, polar compounds
which have relatively low purging efficiencies can be determined
using this method. Such compounds may be more susceptible to matrix
effects, and the quality of the data may be adversely influenced.
1.3 Analytes that are not separated chromatographically, but which have
different mass spectra and noninterfering quantitation ions (Table
1), can be identified and measured in the same calibration mixture
or water sample as long as their concentrations are somewhat similar
(Sect. 11.6.2). Analytes that have very similar mass spectra cannot
be individually identified and measured in the same calibration
mixture or water sample unless they have different retention times
(Sect. 11.6.3). Coeluting compounds with very similar mass spectra,
typically many structural isomers, must be reported as an isomeric
group or pair. Two of the three isomeric xylenes and two of the
three dichlorobenzenes are examples of structural isomers that may
not be resolved on the capillary column, and if not, must be
reported as isomeric pairs. The fnore water soluble compounds (> 2%
solubility) and compounds with boiling points above 200°C are purged
from the water matrix with lower efficiencies. These analytes may
be more susceptible to matrix effects.
2. SUMMARY OF METHOD
2.1 Volatile organic compounds and surrogates with low water solubility
are extracted (purged) from the sample matrix by bubbling an inert
gas through the aqueous sample. Purged sample components are
trapped in a tube containing suitable sorbent materials. When
purging is complete, the sorbent tube is heated and backflushed with
helium to desorb the trapped sample components into a capillary gas
chromatography (GC) column interfaced to a mass spectrometer (MS).
The column is temperature programmed to facilitate the separation of
the method analytes which are then detected with the MS. Compounds
eluting from the GC column are identified by comparing their
measured mass spectra and retention times to reference spectra and
retention times in a data base. Reference spectra and retention
times for analytes are obtained by the measurement of calibration
standards under the same conditions used for samples. Analytes are
quantitated using procedural standard calibration (Sect. 3.14). The
concentration of each identified component is measured by relating
the MS response of the quantitation ion produced by that compound to
the MS response of the quantitation ion produced by a compound that
is used as an internal standard. I Surrogate analytes, whose
concentrations are known in every sample, are measured with the same
internal standard calibration procedure.
524.2-41
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3. DEFINITIONS
3.1 INTERNAL STANDARD (IS) — A pure analyte(s) added to a sample,
extract, or standard solution in known amount(s) and used to measure
the relative responses of other method analytes and surrogates that
are components of the same sample or solution. The internal
standard must be an analyte that is not a sample component.
3.2 SURROGATE ANALYTE (SA) — A pure analyte(s), which ,is extremely
unlikely to be found in any sample, and which is added to a sample
aliquot in known amount(s) before extraction or other processing and
is measured with the same procedures used to measure other sample
components. The purpose of the SA is to monitor method performance
with each sample.
3.3 LABORATORY DUPLICATES (LD1 and LD2) — Two aliquots of the same
sample taken in the laboratory and analyzed separately with
identical procedures. Analyses of LD1 and LD2 indicates precision
associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures.
3.4 FIELD DUPLICATES (FD1 and FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures. Analy-
ses of FD1 and FD2 give a measure of the precision associated with
sample collection, preservation and storage, as well as with labora-
tory procedures.
3.5 LABORATORY REAGENT BLANK ,(LRB) — An aliquot of reagent water or
other blank matrix that is treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents,- internal
standards, ana surrogates that are used with other samples. The LRB
is used to determine if method analytes or other interferences are
present in the laboratory environment, the reagents, or the appara-
tus. •
3.6 FIELD REAGENT BLANK (FRB) -- An aliquot of reagent water or other
blank matrix that is placed in a sample.container in the laboratory
and treated as a sample in all respects, including shipment to the •
sampling site, exposure to sampling site conditions, storage,
preservation, and all analytical procedures. The purpose of the FRB
is to determine if method analytes or other interferences are
present in the field environment.
3.7 LABORATORY PERFORMANCE CHECK SOLUTION (LPC) — A solution of one or
more compounds (analytes, surrogates, internal standard, or other
test compounds) used to evaluate the performance of the instrument
system with respect to a defined set of method criteria.
3.8 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water or
other blank matrix to which known quantities of the method analytes
are added in the laboratory. The LFB is analyzed exactly like a
sample, and its purpose is to determine whether the methodology is
524.2-5
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in control, and whether the laboratory is capable of making accurate
and precise measurements.
3.9 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
3.10 STOCK STANDARD SOLUTION (SSS) —jA concentrated solution containing
one or more method analytes prepared in the laboratory using assayed
reference materials or purchased from a reputable commercial source.
3.11 PRIMARY DILUTION STANDARD SOLUTION (PDS) — A solution of several
analytes prepared in the laboratory from stock standard solutions
and diluted as needed to prepare calibration solutions and other
needed analyte solutions.
3.12 CALIBRATION STANDARD (CAL) -- A solution prepared from the primary
dilution standard solution or stock standard solutions and the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration. !
[
3.13 QUALITY CONTROL SAMPLE (QCS) — A solution of method analytes of
known concentrations which is used to fortify an aliquot of LRB or
sample matrix.' The QCS is obtained from a source external to the
laboratory and different from the source of calibration standards.
It is used to check laboratory performance with externally prepared
test materials. ;
3.14 PROCEDURAL STANDARD CALIBRATION — A calibration method where
aqueous calibration standards are prepared and processed (e.g.
purged,extracted, and/or derivatized) in exactly the same manner as
a sample. All steps in the process from addition of sampling
preservatives through .instrumental analyses are included in the
calibration. Using procedural standard calibration compensates for
any inefficiencies in the processing procedure.
4. INTERFERENCES
4.1 During analysis, major contaminant sources are volatile materials in
the laboratory and impurities in the inert purging gas and in the
sorbent trap. The use of Teflon tubing, Teflon thread sealants, or
flow controllers with rubber components in the purging device should
be avoided since such materials out-gas organic compounds which will
be concentrated in the trap'during the purge operation. Analyses of
• laboratory reagent blanks provide information about the presence of
contaminants. When potential interfering peaks are noted in labora-
tory reagent blanks, the analyst should change the purge gas source
524.2-6
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and regenerate the molecular sieve purge gas filter. Subtracting
blank values from sample results is not permitted.
4.2 Interfering contamination may occur when a sample containing low
concentrations of volatile organic compounds is analyzed immediately
after a sample containing relatively high concentrations of volatile
organic compounds. A preventive technique is between-sample rinsing
of the purging apparatus and sample syringes with two portions of
reagent water. After analysis of a sample containing high
concentrations of volatile organic compounds, one 017 more laboratory
reagent blanks should be analyzed to check for cross-contamination.
4.3 Special precautions must be taken to determine methylene chloride.
The analytical and sample storage area should be isolated from all
atmospheric sources of methylene chloride, otherwise random back-
ground levels will result. Since methylene chloride will permeate
Teflon tubing, all GC carrier gas lines and purge gas plumbing
should be constructed of stainless steel or copper tubing. .
Laboratory worker's clothing should be cleaned frequently since
clothing previously exposed to methylene chloride fumes during
common liquid/liquid extraction procedures can contribute to sample.
contamination. .
4.4 Traces of ketones, methylene chloride, and some other organic sol-
vents can be present even in the highest purity methanol. This is
another potential source of contamination, and should be assessed
before standards are prepared in the methanol.
5. SAFETY
5.1 The toxicity or carcinogenicity of chemicals used in this method has
not been precisely defined; each chemical should be treated as a
potential health hazard, and exposure to these chemicals should be
minimized. Each laboratory is responsible for maintaining awareness
of OSHA regulations regarding safe handling of chemicals used in
this method. Additional references to laboratory safety are
available (4-6) for the information of the analyst.
5.2 The following method analytes have been tentatively classified as
known or suspected human or mammalian carcinogens: benzene, carbon
tetrachloride, 1,4-dichlorobenzene, 1,2-dichlorethane, hexachloro-
butadiene, 1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane, chloro-
form, l,2-dibromoethane,tetrachloroethene, trichloroethene, and
vinyl chloride. Pure standard materials and stock standard
solutions of these compounds should be handled in a hood. A
NIOSH/MESA approved toxic gas respirator should be worn when the
analyst handles high concentrations of these toxic compounds.
6. EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.) '
6.,1 SAMPLE CONTAINERS— 40-mL to 120-mL screw cap vials each equipped
with a Teflon faced silicone .septum. Prior to use, wash vials and
septa with detergent and rinse with tap and distilled water. Allow
524.2-7
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the vials and septa to air dry at r^oom temperature, place in a 105°C
oven for 1 hr, then remove and allow to cool in an area known to be
free of organics.
6.2 PURGE AND TRAP SYSTEM — The purge and trap system consists of three
separate pieces of equipment: purging device, trap, and desorber.
Systems are commercially available from several sources that meet
all of the following specifications.
6.2.1 The all glass purging device (Figure 1) should be designed to
accept 25-mL samples with a water column at least 5 cm deep.
A smaller (5-mL) purging device is recommended if the GC/MS
system has adequate sensitivity to obtain the method detec-
tion limits required. Gaseous volumes above the sample must
be kept to a minimum (< 15 ml) to eliminate dead volume
effects. A glass frit should be installed at the base of the
sample chamber so the purge gas passes through the water
column as finely divided bubbles with a diameter of < 3 mm at
the origin. Needle spargers may be used, however, the purge
gas must be introduced at a point about 5 mm from the base of
the water column. The use of a moisture control device is
recommended to prohibit much of the trapped water vapor from
entering the GC/MS and event'ually causing instrumental prob-
1 ems.
6.2.2 The trap (Figure 2) must be at least 25 cm long and have an
inside diameter of at least 0.105 in. Starting from the
inlet, the trap should contain 1.0 cm of methyl silicone
coated packing and the following amounts of adsorbents: 1/3
of 2,6-diphenylene oxide polymer, 1/3 of silica gel, and 1/3
of coconut charcoal. If it is not necessary to determine
dichlorodifluoromethane, the charcoal can be eliminated and
the polymer increased to fill 2/3 of the trap. Before ini-
tial use, the trap should be conditioned overnight at 180°C
by backflushing with an inert gas flow of at least 20 mL/min.
Vent the trap effluent to the room, not to the analytical
column. Prior to daily use, the trap should be conditioned
for 10 min at 180°C with backflushing. The trap may be
vented to the analytical column during daily conditioning;
however, the column must be run through the temperature
program prior to analysis of samples. The use of alternative
sorbents is acceptable provided the data acquired meets all
quality control criteria described in Section 9, and provided
the purge and desorption procedures specified in Section 11
of the method are not changed. Specifically, the purging
time, the purge gas flow rate, and the desorption time may
not be changed. Since many of the potential alternate
sorbents may be thermally stable above 180°C, alternate traps
may be desorbed and baked out at higher temperatures than
those described in Section 11. If higher temperatures are
used, the analyst should monitor the data for possible
analyte and/or trap decomposition.
524.2-8
-------
6.2.3 The use of the methyl silicone coated packing is recommended,
but not mandatory. The packing serves a dual purpose of
protecting the Tenax adsorbant from aerosols, and also of
insuring that the Tenax is fully enclosed within the heated
zone of the trap thus eliminating potential cold spots.
Alternatively, silanized glass wool may be used as a spacer
at the trap inlet.
6.2.4, The desorber (Figure 2) must be capable of rapidly heating
the trap to 180°C either prior to or at the beginning of the
flow of desorption gas. The polymer section of the trap
should not be heated higher than 200°C or the life expectancy
of the trap will decrease. Trap failure is characterized by
a pressure drop in excess of 3 lb/in2 across the trap during
purging or by poor bromoform sensitivities. The desorber
design illustrated in Fig. 2 meets these criteria.
6.3 GAS CHROMATOGRAPHY/MASS SPECTROMETER/DATA SYSTEM (GC/MS/DS)
6.3.1 The GC must be capable of temperature programming and should
be equipped with variable-constant differential flow control-
lers so that the column flow rate will remain constant
throughout desorption and temperature program operation. If
the column oven is to be cooled to 10°C or lower, a subam-
bient oven controller will likely be required. If syringe
injections of 4-bromofluorobenzene (BFB) will be used, a
split/splitless injection port is required.
6.3.2 Capillary GC Columns. Any gas chromatography column that
meets the performance specifications of this method may be
used (Sect. 10.2.4.1). Separations of the calibration mix-
ture must be equivalent or better than those described in
this method. Four useful columns have been evaluated, and
observed compound retention times for these columns are
listed in Table 2.
6.3.2.1 Column 1 — 60 m x 0.75 mm ID VOCOL (Supelco, Inc.)
glass wide-bore capillary with a 1.5 /^m film thick-
ness.
Column 2 — 30 m x 0'.53 mm ID DB-624 (J&W Scien-
tific, Inc.) fused silica capillary with a 3 p,m film
thickness.
Column 3 — 30 m x 0.32 mm ID DB-5 (J&W Scientific,
Inc.) fused silica capillary with a 1 /zm film thick-
ness.
Column 4 — 75 m x 0.53 mm id DB-624 (J&W Scien-
tific, Inc.) fused, silica capillary with a 3 IM film
thickness.
6.3.3 Interfaces between the GC and MS. The interface used depends
on the column selected and the gas flow rate.
524.2-9
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6.3.3.1 The wide-bore columns 1, 2, and 4 have the capacity
to accept the standard gas flows from the trap
during thermal desorption, and chromatography can
begin with the onset of thermal desorption. Depend-
ing on the pumping capacity of the MS, an additional
interface between the end of the column and the MS
may be required. An open split interface (7) or an
all-glass jet separator is an acceptable interface.
Any interface can be used if the performance speci-
fications described in this method (Sect. 9 and 10)
can be achieved. The end of the transfer line after
the interface, or the end of the analytical column
if no interface is usedj should be placed within a
few mm of the MS ion source.
6.3.3.2 When narrow bore column ;3 is used, a cryogenic
interface placed just in front of the column inlet
is suggested. This interface condenses the desorbed
sample components in a narrow band on an uncoated
fused silica precolumn using liquid nitrogen cool-
ing. When all analytes have been desorbed from the
trap, the interface is rapidly heated to transfer
them to the analytical column. The end of the ana-
lytical column should be placed within a few mm of
the MS ion source. A potential problem with this
interface is blockage of the interface by frozen
water from the trap. This condition will result in
a major loss in sensitivity and chromatographic
resolution.
6.3.4 The mass spectrometer must be capable of electron ionization
at a nominal electron energy of 70 eV. The spectrometer must
be capable of scanning from 35 to 260 amu with a complete
scan cycle time (including scan overhead) of 2 sec or less.
(Scan cycle time = Total MS data acquisition time in seconds
divided by number of scans in the chromatogram.) The spec-
trometer must produce a mass spectrum that meets all criteria
in Table 3 when 25 ng or less of 4-bromofluorobenzene (BFB)
is introduced into the GC. An average spectrum across the
BFB GC peak may be used to test instrument performance.
6.3.5 An interfaced data system is required to acquire, store,
reduce, and output mass spectral data. The computer software
should have the capability of processing stored GC/MS data by
recognizing a GC peak within any given retention time window,
comparing the mass spectra from the GC peak with spectral
data in a user-created data base, and generating a list of
tentatively identified compounds with their retention times
and scan numbers. The software must allow integration of the
ion abundance of any specific ion between specified time or
scan number limits. The software should also allow calcula-
tion of response factors as defined in Sect. 10.2.6 (or
construction of a linear or second order regression calibra-
tion curve), calculation of response factor statistics (mean
and standard deviation), and calculation of concentrations of
524.2-10
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analytes using either the calibration curve or the equation
in Sect. 12.
6.4 SYRINGE AND SYRINGE VALVES
6.4.1 Two 5-mL or 25-mL glass hypodermic syringes with Luer-Lok tip
(depending on sample volume used).
6.4.2 Three 2-way syringe valves with Luer ends.
6.4.3 Micro syringes - 10, 100 ill.
6.4.4 Syringes - 0.5, 1.0, and 5-mL, gas tight with shut-off valve.
6.5 MISCELLANEOUS
6.5.1 Standard solution storage containers — 15-mL bottles with
Teflon lined screw caps.
7. REAGENTS AND STANDARDS
7.1 TRAP PACKING MATERIALS
7.1.1 2,6-Diphenylene oxide polymer, 60/80 mesh, chromatographic
grade (Tenax GC or equivalent).
7.1.2 Methyl silicone packing (optional) — OV-1 (3%) on Chromosorb
W, 60/80 mesh, or equivalent.
7.1.3 Silica gel — 35/60 mesh, Davison, grade 15 or equivalent.
7.1.4 Coconut charcoal — Prepare from Barnebey Cheney, CA-580-26
lot #M-2649 (or equivalent) by crushing through 26 mesh
screen.
7.2 REAGENTS-
7.2.1 Methanol — Demonstrated to be free of analytes.
7.2.2 Reagent water — Prepare reagent water by passing tap water
through a filter bed containing about 0.5 kg of activated
carbon, by using a water purification system, or by boiling
distilled water for 15 min followed by a 1-h purge with inert
gas while the water temperature is held at 90 C. Store in
clean, narrow-mouth bottles with Teflon lined septa and screw
caps.
7.2.3 Hydrochloric acid (1+1) — Carefully add measured volume of
cone. HC1 to equal volume of reagent water.
7.2.4 Vinyl chloride — Certified mixtures of vinyl chloride in
nitrogen and pure vinyl chloride are available from several
sources (for example, Matheson, Ideal Gas Products, and Scott
Gases).
7.2.5 Ascorbic acid — ACS reagent grade, granular.
524.2-11
-------
7.2.6 Sodium thiosulfate — ACS reagent grade, granular.
7.3 STOCK STANDARD SOLUTIONS — These solutions may be purchased as
certified solutions or prepared from pure standard materials using
the following procedures. One of these solutions is required for
every analyte of concern, every surrogate, and the internal stan-
dard. A useful working concentration is about 1-5 mg/mL.
7.3.1 Place about 9.8 ml of methanol into a 10-mL ground-glass
stoppered volumetric flask. Allow the flask to stand,
unstoppered, for about 10 miii or until all alcohol-wetted
surfaces have dried and weigh to the nearest 0.1 mg.
7.3.2 If the analyte is a liquid at room temperature, use a 100-/iL
syringe and immediately add two or more drops of reference
standard to the flask. Be sure that the reference standard
falls directly into the alcohol without contacting the neck
of the flask. If the analyte is a gas at room temperature,
fill a 5-mL valved gas-tight syringe with the standard to the
5.0-mL mark, lower the needle to 5 mm above the methanol
meniscus, and slowly inject the standard into the neck area .
of the flask. The gas will rapidly dissolve in the methanol.
7.3.3 Reweigh, dilute to volume, stopper, then mix by inverting the
flask several times. Calculate the concentration in /KJ//ZL
from the net gain in weight. When compound purity is certi-
fied at 96% or greater, the weight can be used without cor-
rection to calculate the concentration of the stock standard.
7.3..4 Store stock standard solutions in 15-mL bottles equipped with
Teflon lined screw caps. Methanol solutions of acryloni-
trile, methyl iodiae, and methyl acrylate are stable for only
one week at 4°C. Methanol solutions prepared from other
liquid analytes are stable for at least 4 weeks when stored
at 4°C. Methanol .solutions prepared from gaseous analytes
are not stable for more than 1 week when stored at < 0°C; at
room temperature, they must be discarded after 1 day.
7.4 PRIMARY DILUTION STANDARDS -- Use stock standard solutions to
prepare primary dilution standard solutions that contain all the
analytes of concern in methanol or other suitable solvent. The
primary dilution standards should be prepared at concentrations that
can be easily diluted to prepare aqueous calibration solutions that
will bracket the working concentration range. Store the primary
dilution standard solutions with minimal headspace and check fre-
quently for signs of deterioration or evaporation, especially just
before preparing calibration solutions. Storage times described for
stock standard solutions in Sect. 7.3.4 also apply to primary
dilution standard solutions.
7.5 FORTIFICATION SOLUTIONS FOR INTERNAL STANDARD AND SURROGATES
7.5.1 A solution containing the internal standard and the surrogate
compounds is required to prepare laboratory reagent blanks
524.2-12
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(also used as a laboratory performance check solution), and
to fortify each sample. Prepare a fortification solution
containing fluorobenzene (internal standard), 1,2- dichloro-
benzene-d4 (surrogate), and BFB (surrogate) in methanol at
concentrations of 5 /tg/mL of each (any appropriate concentra
tion is acceptable). A 5-fil aliquot of this solution added
to a 25-mL water sample volume gives concentrations of 1 jug/L
of each. A 5-#L aliquot of this solution added to a 5-mL
water sample volume gives a concentration of 5 /jg/L of each.
Additional internal standards and surrogate analytes are
optional. Additional surrogate compounds should be similar
in physical and chemical characteristics to the analytes of
concern.
7.6 PREPARATION OF LABORATORY REAGENT BLANK (LRB) — Fill a 25-mL (or
5-mL) syringe with reagent water and adjust to the mark (no air
bubbles). Inject an appropriate volume of the fortification solu-
tion containing the internal standard and surrogates through the
Luer Lok valve into the reagent water. Transfer the LRB to the
purging device. See Sect. 11.1.2.
7.7 PREPARATION OF LABORATORY FORTIFIED BLANK - Prepare this exactly
like a calibration standard (Sect. 7.8). This is a calibration
standard that is treated as a sample.
7.8 PREPARATION OF CALIBRATION STANDARDS
7,8.1 The number of calibration solutions (CALs) needed depends on
the calibration range desired. A minimum of three CAL solu-
tions is required to calibrate a range of a factor of 20 in
concentration. For a factor of 50, use at least four stan-
dards, and for a factor of 100 at least five standards. One
calibration standard should contain each analyte of concern
at a concentration of 2-10 times the method detection limit
(Tables 4, 5, and 7) for that compound. The other CAL stan-
dards should contain each analyte of concern at concentra-
tions that define the range of the method. Every CAL solu-
tion contains the internal standard and the surrogate com-
pounds at the same concentration (5 /ig/L suggested for a 5-mL
sample; 1 /zg/L for a 25-mL sample).
7.8.2 To prepare a .calibration standard, add an appropriate volume
of a primary dilution standard containing all analytes of
concern to an aliquot of acidified (pH 2) reagent water in a
volumetric flask. Also add an appropriate volume of internal
standard and surrogate compound solution from Sect. 7.5.1.
Use a microsyringe and rapidly inject the methanol solutions
into the expanded area of the filled volumetric flask.
Remove the needle as quickly as possible after injection.
Mix by inverting the flask three times only. Discard the
contents contained in the neck of the flask. Aqueous stan-
dards are not stable in a volumetric flask and should be
discarded after 1 hr unless transferred to a sample bottle
and sealed immediately. Alternately, aqueous calibration
524.2-13
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standards may be prepared in a gas tight, 5 mL or 25 mL sy-
ringe. NOTE: If'unacidified samples are being analyzed for
THMs only, calibration standards should be prepared without
acid.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 SAMPLE COLLECTION AND DECHLORINATION
8.1.1 Collect all samples in duplicate. If samples, such as fin-
ished drinking water, are suspected to contain residual chlo-
rine, add about 25 mg of ascorbic acid per 40 mL of sample to
the sample bottle before filling. If analytes that are gases
at room temperature (such as vinyl chloride), or analytes in
Table 7 are not to be determined, sodium thiosulfate is
recommended to reduce the residual chlorine. Three milli-
grams of sodium thiosulfate should be added for each 40 mL of
water sample.
NOTE: If the residual chlorine is likely to be present > 5
mg/L, a determination of the amount of the chlorine may be
necessary. Diethyl-p-phenylenediamine (DPD) test kits are
commercially available to determine residual chlorine in the
field. Add an additional 25 mg of ascorbic acid or 3 mg of
sodium thiosulfate per each 5 mg/L of residual chlorine.
8.1.2 When sampling from a water tap, open the tap and allow the
system to flush until the water temperature has stabilized
(usually about 10 min). Adjust the flow to about 500 mL/min
and collect duplicate samples containing the desired dechlo-
rinating agent from the flowing stream.
8.1.3 When sampling from an open body of water, partially fill a
1-quart wide-mouth bottle or 1-L beaker with sample from a
representative area. Fill duplicate sample bottles contain-
ing the desired dechlorihating agent with sample from the
larger container.
8.1.4 Fill sample bottles to overflowing, but take care not to
flush out the rapidly dissolving dechlorinating agent. No
air bubbles should pass through the sample as the bottle is
filled, or be trapped in the sample when the bottle is
sealed.
8,2 SAMPLE PRESERVATION
8.2.1 Adjust the pH of all samples to < 2 at the time of collect-
ion, but after dechlorination, by carefully adding two drops
of 1:1 HC1 for each 40 mL of sample. Seal the sample bot-
tles, Teflon face down, anci mix for 1 min. Exceptions to the
acidification requirement are detailed in Sections 8.2.2 and
8.2.3. NOTE: Do not mix the ascorbic acid or sodium thiosul-
fate with the HC1 in the sample bottle prior to sampling.
524.2-14
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8.2.2 When sampling for THM analysis only, acidification may be
omitted if sodium thiosulfate is used to dechlorinate the
sample. This exception to acidification does not apply if
ascorbic acid is used for dechlorination.
8.2.3
8.2.4
If a sample foams vigorously when HC1 is added, discard that
sample. Collect a set of duplicate samples but do not acidi-
fy them. These samples must be flagged as "not acidified"
and must be stored at 4°C or below. These samples must be
analyzed within 24 hr of collection time if they are to be
analyzed for any compounds other than THMs.
The samples must be chilled to about 4°C when collected and
maintained at that temperature until analysis. Field samples
that will not be received at the laboratory on the day of
collection must be packaged for shipment with sufficient ice
to ensure that they will arrive at the laboratory with a
substantial amount of ice remaining in the cooler.
8.2 SAMPLE'STORAGE • '
8.2.1 Store samples at < 4°C until analysis. The sample storage
area must be free of organic solvent vapors and direct or
. ". intense light.
8.2.2 Analyze all samples within 14 days of collection. Samples
not analyzed within this period must be discarded and re-
placed. '
8.3 FIELD REAGENT BLANKS (FRB)
8.3.1 Duplicate FRBs must be handled along with each sample set,
which is composed of the samples collected from the same
general sample site at approximately the same time. At the
laboratory, fill field blank sample bottles with reagent
water and sample preservatives, seal, and ship to the sam-
pling site along with empty sample bottles and back to the
laboratory with.filled sample bottles. Wherever a set of
samples is shipped and stored,, it is.accompanied by appropri-
ate blanks. FRBs must remain hermetically sealed until
analysis.
8.3.2 Use the same procedures used for samples to add ascorbic acid
and HC1 to blanks (Sect. 8.1.1). The same batch of ascorbic
acid and HC1 should be used for the field reagent blanks as
for the field samples.
9. QUALITY CONTROL .
9.1 Quality control (QC) requirements are the initial demonstration of
laboratory capability followed by regular analyses of laboratory
reagent blanks, field reagent blanks, and laboratory fortified
blanks. A MDL for each analyte must also be determined. Each
524.2-15
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laboratory must maintain records to document the quality of the data
generated. Additional quality control practices are recommended.
9.2 Initial demonstration of low system background. Before any samples
are analyzed, it must be demonstrated that a laboratory reagent
blank (LRB) is reasonably free of contamination that would prevent
the determination of any analyte of concern. Sources of background
contamination are glassware, purge gas, sorbents, reagent water, and
equipment. Background contamination must be reduced to an accept-
able level before proceeding with the next section. In general,
background from method analytes should be below the method detection
limit.
9.3 Initial demonstration of laboratory accuracy and precision. Analyze
four to seven replicates of a laboratory fortified blank containing
each analyte of concern at a concentration in the range of 2-5 fig/L
depending upon the calibration range of the instrumentation.
9.3.1 Prepare each replicate by adding an appropriate aliquot of a
quality control sample to reagent water. It is recommended
that a QCS from a source different than the calibration
standards be used for this set of LFBs, since it will serve
as a check to verify the accuracy of the standards used to
generate the calibration curve. This is particularly useful
if the laboratory is using the method for the first time, and
has no historical data base for standards. Prepare each
replicate by adding an appropriate aliquot of a quality
control sample to reagent water. Also add the appropriate
amounts of internal standard and surrogates. If it is ex-
pected that field samples will contain a dechlorinating agent
and HC1, then add these to the LFBs in the same amounts pro-
scribed in Sect. 8.1.1. If only THMs are to be determined
and field samples do not contain HC1, then do not acidify
LFBs. Analyze each replicate according to the procedures de-
scribed in Section 11.
9.3.2 Calculate the measured concentration of each analyte in each
replicate, the mean concentration of each analyte in all
replicates, and mean accuracy (as mean percentage of true
value) for each analyte, and the precision (as relative
standard deviation, RSD) of the measurements for each
analyte.
i
I
9.3.3 Some analytes, particularly early eluting gases and late
eluting higher molecular weight compounds, will be measured
with less accuracy and precision than other analytes. Howev-
er, the accuracy and precision for all analytes must fall
within the limits expressed below. If these criteria are not
met for an analyte of interest, take remedial action and
repeat the measurements for that analyte until satisfactory
performance is achieved. For each analyte, the mean accuracy
must be 80-120% (i-e- an accuracy of ± 20%). The precision
524.2-16
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of the recovery (accuracy) for each analyte must be less than
twenty percent (<20%). These criteria are different than the
± 30/0 response factor criteria specified in Sect. 10.3.5
The criteria differ, because the measurements in Sect.'gis.S
as part of the initial demonstration of capability are meant
to be more stringent than the continuing calibration measure-
ments in Sect. 10.3.5.
9.3.4 To determine the MDL, analyze a minimum of 7 LFBs prepared at
a low concentration. MDLs in Table 5 were calculated from
samples fortified from 0.1-0.5 /jg/L, which can be used as a
guide, or use calibration data to estimate a concentration
for .each analyte that will yield a peak with a 3-5 signal to
noise response. Analyze the 7 replicates as described in
Sect.11, and on a schedule that results in the analyses being
conducted over several days. Calculate the mean accuracy and
standard deviation for each analyte. Calculate the MDL usinq
the equation in Sect. 13.
9.3.5 Develop and maintain 'a system of control, charts to plot the
• precision and accuracy of analyte and surrogate measurements
as a function of time. Charting surrogate recoveries is an
especially valuable activity because surrogates are present
in every sample and the analytical results will form a sig-
nificant record of data quality.
9.4 Monitor the integrated areas of the quantitation ions of the inter-
nal standards and surrogates (Table 1) in all samples, continuing
calibration checks, and blanks. These should remain reasonably
constant over time. An abrupt change may indicate a matrix effect
or an instrument problem. If a cryogenic interface is utilized it
may indicate an inefficient transfer from the trap to the column.
These samples must be reanalyzed or a laboratory fortified duplicate
sample analyzed to test for matrix effect. A more gradual drift of
more than 50% in any area is indicative of a loss in sensitivity
and the problem must be found and corrected. '
9.5 LABORATORY REAGENT BLANKS (LRB) - With each batch of samples pro-
cessed as a group within a work shift, analyze a LRB to determine
the background system contamination.
9.6 Assessing Laboratory Performance. Use the procedures and criteria
in Sects. 10.3.4 and 10.3.5 to evaluate the accuracy of the measure-
ment of the laboratory fortified blank (LFB), which must be analyzed
with each batch of samples that is processed as a group within a
work shift. If more than 20 samples are in a work shift batch
analyze one LFB per 20 samples. Prepare the LFB with the concentra-
tion of each analyte that was used in the Sect. 9.3.3 analysis. If
the acceptable accuracy for this measurement (±30%) is not achieved
the problem must be solved before additional samples may be reliably
analyzed. Acceptance criteria for the IS and surrogate given in
Sect.10.3.4 also applies to this LFB.
524.2-17
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Since the calibration check sample in Sect. 10.3.5 and the LFB are
made the same way and since procedural standards are used, the
sample analyzed here may also be used as a calibration check in
Sect. 10.3.5. Add the results of the LFB analysis to the control
charts to document data quality. ,
9.7 If a water sample is contaminated with an analyte, verify that it is
not a sampling error by analyzing a field reagent blank. The
results of these analyses will help define contamination resulting
from field sampling, storage and transportation activities. If the
field reagent blank shows unacceptable contamination, the analyst
should identify and eliminate the contamination.
9.8 At least quarterly, replicate LFB data should be evaluated to
determine the precision of the laboratory measurements. Add these
results to the ongoing control charts to document data quality.
9.9 At least quarterly, analyze a quality control sample (QCS) from an
external source. If measured analyte concentrations are not of
acceptable accuracy, check the entire analytical procedure to locate
and correct the problem source.
9.10 Sample matrix effects have not been observed when this method is
used with distilled water, reagent water, drinking water, or ground
water. Therefore, analysis of a laboratory fortified sample matrix
(LFM) is not required unless the criteria in Section 9.4 are not
met. If matrix effects are observed or suspected to be causing low
recoveries, analyze a laboratory fortified matrix sample for that
matrix. The sample results' should be flagged and the LFM results
should be reported with them.
9.11 Numerous other quality control measures are incorporated into other
parts of this procedure, and serve to alert the analyst to potential
problems.
10. CALIBRATION AND STANDARDIZATION
10.1 Demonstration and documentation of acceptable initial calibration is
required before any samples are analyzed. In addition, acceptable
performance must be confirmed intermittently throughout analysis of
samples by performing continuing calibration checks. These checks
are required at the beginning of each work shift, but no less than
every 12 hours. Additional periodic calibration checks are good
laboratory practice. , It is highly recommended that an additional
calibration check be performed at the end of any cycle of continuous
instrument operation, so that each set of field samples is bracketed
by calibration check standards. NOTE: Since this method uses
procedural standards, the analysis of the laboratory fortified
blank, which is required in Sect, 9.6, may be used here as a cali-
bration check sample.
10.2 INITIAL CALIBRATION
524.2-18
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10.2.1 Calibrate the mass and abundance scales of the MS with cali-
bration compounds and procedures prescribed by the manufac-
turer with any modifications necessary to meet the require-
ments in Sect. 10.2.2.
10.2.2 Introduce into the GC (either by purging a laboratory reagent
blank or making a syringe injection) 25 ng or less of BFB and
acquire mass spectra for m/z 35-260 at 70 eV (nominal). Use
the purging procedure and/or GC conditions given in Sect. 11.
If the spectrum does not meet all criteria in Table 3, the MS
. must be returned and adjusted to meet all criteria before
proceeding with calibration. An average spectrum across the
.GC peak may be used to evaluate the performance of the sys-
tem.
10.2.3 Purge a medium CAL solution, (e.g., 10-20 /ig/L) using the
procedure given in Sect. 11.
10.2.4 Performance criteria for calibration standards. Examine the
stored GC/MS data with the data system software. Figures 3
and 4 shown acceptable total ion chromatograms.
10.2.4.1 GC performance. Good column performance will pro-
duce symmetrical peaks with minimum tailing for most
compounds. If peaks are unusually broad, or if
there is poor resolution between peaks, the wrong
column has .been selected or remedial action is
probably necessary (Sect. 10.3.6) .
10.2.4.2 MS sensitivity. The GC/MS/DS peak identification
software should be able to recognize a GC peak in
the appropriate retention time window for each of
the compounds in calibration solution, and make
correct tentative identifications. If fewer than
99% of the compounds are recognized, system mainte-
nance is required. See Sect. 10.3.6.
10.2.5 If all performance criteria are met, purge an aliquot of each
of the other CAL solutions using the same GC/MS conditions.
10.2.6 Calculate a response factor (RF) for each analyte and isqmer
pair for each CAL solution using the internal standard fluor-
obenzene. Table 1 contains suggested quantitation ions for
all compounds. This calculation is supported in acceptable
GC/MS data system software (Sect. 6.3.5), and many other
software programs. RF is a unitless number, but units used
to express quantities of analyte and internal standard must
be equivalent.
RF = (AxHQ.Js)
524.2-19
-------
where: Ax = integrated abundance of the quantitation ion
of the analyte.
Afs = integrated abundance of the quantitation ion
of the internal standard.
Qx = quantity of analyte purged in nanograms or
concentration units.
Qjs = quantity of internal standard purged in ng or
concentration units.
10.2.6.1 For each analyte and surrogate, calculate the mean
RF from analyses of CAL solutions. Calculate the
standard deviation (SD) and the relative standard
deviation (RSD) from each mean: RSD = 100 (SD/M).
If the RSD of any analyte or surrogate mean RF
exceeds 20%, either analyze additional aliquots of
appropriate CAL solutions to obtain an acceptable
RSD of RFs over the entire concentration range, or
take action to improve GC/MS performance Sect.
10.3.6). Surrogate compounds are present at the
same concentration on every sample, calibration
standard, and all types of blanks.
10.2.7 As an alternative to calculating mean response factors and
applying the RSD test, use the GC/MS data system software or
other available software to generate a linear or second order
regression calibration curve, by plotting A/Ais vs. Qx.
10.3 CONTINUING CALIBRATION CHECK — Verify the MS tune and initial
calibration at the beginning of each 12-hr work shift during which
analyses are performed using the following procedure. Additional
periodic calibration checks are good laboratory practice. It is
highly recommended that an additional calibration check be performed
at the end of any cycle of continuous instrument operation, so that
each set of field samples is bracketed by calibration check stan-
dards.
10.3.1 Introduce into the GC (either by purging a laboratory reagent
blank or making a syringe injection) 25 ng or less of BFB and
acquire a mass spectrum that includes data for m/z 35-260.
If the spectrum does not meet all criteria (Table 3), the MS
must be returned and adjusted to meet all criteria before
proceeding with the continuing calibration check.
10.3.2 Purge a CAL solution and analyze with the same conditions
used during the initial calibration. Selection of the con-
centration level of the calibration check standard should be
varied so that the calibration is verified at more than one
point over the course of several days.
10.3.3 Demonstrate acceptable performance for the criteria shown in
Sect. 10.2.4.
524.2-20
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10.3.4 Determine that the absolute areas of the quantitation ions of
the internal standard and surrogates have not decreased by
more than 30% from the areas measured in the most recent
continuing calibration check, or by more than 50% from the
areas measured during initial calibration. If these are.as
have decreased by more than these amounts, adjustments must
be made to restore system sensitivity. These adjustments may
require cleaning of the MS ion source, or other maintenance
as indicated in Sect. 10.3.6, and recalibration. Control
charts are useful aids in documenting system sensitivity
changes.
10.3.5 Calculate the RF for each analyte of concern and surrogate ,
compound from the data measured in the continuing calibration
check. The RF for each analyte and surrogate must .be within
30% of the mean value measured in the initial calibration.
Alternatively, if a linear or second order regression is
used, the concentration measured using the calibration curve
must be within 30% of the true value of the concentration in'
the calibration solution. If these conditions do not exist,
remedial action must be taken which may require recalibrati-
on. All data from field samples obtained after the last
successful calibration check standard, should be considered
suspect. After remedial action has been taken, duplicate
samples should be analyzed if they are available.
10.3.6 Some possible remedial actions. Major maintenance such as
cleaning an ion source, cleaning quadrupole rods, etc. re-
quire returning to the initial calibration step.
10.3.6.1 Check and adjust GC and/or f'S operating conditions;
check the MS resolution, and calibrate the mass
scale.
10.3.6.2 Clean or replace the splitless injection liner;
silanize a new injection liner. This applies only
if the injection liner is an integral part of the
system.
10.3.6.3 Flush the GC column with solvent according to manu-
facturer's instructions.
10.3.6.4 Break off a short portion (about 1 meter) of the
column from the end near the injector; or replace GC
column. This action will cause a slight change in
retention times. Analyst may need to redefine
retention windows.
10.3.6.5 Prepare fresh CAL solutions, and repeat the initial
calibration step. .
10.3.6.6 Clean the MS ion source and rods (if a quadrupole).
524.2-21
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10.3.6.7 Replace any components that allow analytes to come
into contact with hot metal surfaces.
10.3.6.8 Replace the MS electron multiplier, or any other
faulty components.;
10.3.6.9 Replace the trap, especially when only a few com-
pounds fail the criteria in Sect. 10.3.5 while the
majority are determined successfully. Also check
for gas leaks in the purge and trap unit as well as
the rest of the analytical system.
I
10.4 Optional calibration for vinyl chloride using a certified gaseous
mixture of vinyl chloride in nitrogen can be accomplished by the
following steps.
10.4.1 Fill the purging device with 25.0 ml (or 5-mL) of reagent
water or aqueous calibration standard.
10.4.2 Start to purge the aqueous mixture. Inject a known volume ,
(between 100 and 2000 /zL) of the calibration gas (at room
temperature) directly into the purging device with a gas
tight syringe. Slowly inject the gaseous sample through a
septum seal at the top of the purging device at 2000 /uL/min.
If the injection of the standard is made through the aqueous
sample inlet port, flush the dead volume with several mL of
room air or carrier gas. Inject the gaseous standard before
5 min of the 11-min purge time have elapsed.
10.4.3 Determine the aqueous equival
chloride standard, in
where
S = 0.102 (C)(V)
ent concentration of vinyl
injected with the equation:
S = Aqueous equivalent concentration
of vinyl chloride standard in
C - Concentration of gaseous standard in mg/L (v/v);
V = Volume of standard injected in mL.
11. PROCEDURE
11.1 SAMPLE INTRODUCTION AND PURGING
I
11.1.1 This method is designed for a 25-mL or 5-mL sample volume,
but a smaller (5 mL) sample volume is recommended if the
GC/MS system has adequate sensitivity to achieve the required
method detection limits. Adjust the helium purge gas flow
rate to 40 mL/min. Attach the trap inlet to the purging
device and open the syringe valve on the purging device.
11.1.2 Remove the plungers from two 25-mL (or 5-mL depending on
sample size) syringes and attach a closed syringe valve to
each. Warm the sample to room temperature, open the sample
524.2-22
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. botMe, and carefully pour the sample into one of the syringe
barrels to just short of overflowing. Replace the syringe
plunger, invert the syringe, and compress the sample Open
the syringe valve and vent any residual air while adjusting
the sample volume to 25.0-mL (or 5-mL). To all samples,
blanks, and calibration standards, add 5-//L (or an appropri-
ate volume) of the fortification solution containing the
internal standard and the surrogates to the sample through
the syringe valve. Close the valve. Fill the second syringe
in an identical manner from the same sample bottle. Reserve
this second syringe for a reanalysis if necessary.
11.1.3 Attach the sample syringe valve to the syringe valve on the
purging device. Be sure that the trap is cooler than 25°C,
then open the sample syringe valve and inject the sample into
the purging chamber. Close both valves and initiate purging
Purge the sample for 11.0 min at ambient temperature.
11.1.4 Standards and samples must be analyzed in exactly the same
manner. Room temperature must be reasonably constant, and
changes in excess of 10°F will adversely affect the accuracy
and precision of the method.
11.2 SAMPLE DESORPTION
11.2.1 Non-cryogenic interface — After the 11-min purge, place the
purge and trap system in the desorb mode and preheat the trap
to 180 C without a flow of desorption gas. Then simultan-
eously start the flow of desorption gas at a flow rate suit-
able for the column being used (optimum desorb flow rate is
15 mL/min) for about 4 min, begin the GC temperature program
and start data acquisition.
11.2.2 Cryogenic interface — After the 11-min purge, place the
purge and trap system in the desorb mode, make sure the
cryogenic interface is a -150°C or lower, and rapidly heat
the trap to 180°C while backflushing with an inert gas at
4 mL/min for about 5 min. At the end of the 5 min desorption
cycle, rapidly heat the cryogenic trap to 250°C, and simulta-
neously begin the temperature program of the gas chromato-
graph, and start data acquisition.
11.2.3 While the trapped components are being introduced into the
gas chromatograph (or cryogenic interface), empty the purging
device using the sample syringe and wash the chamber with two
25-mL flushes of reagent water1. After the purging device has
been emptied, leave syringe valve open to allow the purge gas
to vent through the sample introduction needle.
11.3 GAS CHROMATOGRAPHY/MASS SPECTROMETRY — Acquire and store data over
the nominal mass range 35-260 with a total .cycle time (including
scan overhead time) of 2 sec or less. If water, methanol, or carbon
dioxide cause a background problem, start at 47 or 48 m/z. If
524.2-23
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ketones are to be determined, data must be acquired starting at m/z
43. Cycle time must be adjusted to measure five or more spectra
during the elution of each GC peak, Suggested temperature programs
are provided below. Alternative temperature programs can be used.
11.3.1 Single ramp linear temperature program for wide bore column 1
and 2 with a jet separator. Adjust the helium carrier gas
flow rate to within the capacity of the separator, or about
15 mL/min. The column temperature is reduced 10°C and held
for 5 min from the beginning of desorption, then programmed
to 160°C at 6°C/min, and held until all components have
eluted.
11.3.2 Multi-ramp temperature program for wide bore column 2 with,,.
the open split interface. Adjust the helium carrier :gas flow
rate to about 4.6 mL/min. Jhe column temperature is reduced
to 10°C and held for 6 min from the beginning of desorption,
then heated to 70°C at 10°/m,in, heated to 120°C at 5°/min,
heated to 180° at 8°/min, and held at 180° until all com-
pounds have eluted.
11.3.3 Single ramp linear temperature program for narrow bore column
3 with a cryogenic interface. Adjust the helium carrier gas
flow rate to about 4 mL/min. The column temperature is
reduced to 10°C and held for 5 min from the beginning of
vaporization from the cryogenic trap, programmed at 6°/min
for 10 min, then 15°/min for 5 min to 145°C, and held until
all components have eluted.
11 3 4*Multi-ramp temperature program for wide bore column 4 with
the open split interface. Adjust the helium carrier gas flow
rate to about 7.0 mL/min. The column temperature is - 10°C
and held for 6 min. from beginning of desorption, then heated
to 100°C at 10°C/min, heated to 200°C at 5°C/min and held at
200°C for 8 min or until all compounds of interest had elut-
ed. . !
11.4 TRAP RECONDITIONING — After describing the sample for 4 min, recon-
dition the trap by returning the purge and trap system to the
purge mode. Wait 15 sec, then close the syringe valve on the
purging device to begin gas flow through the trap. Maintain the
trap temperature at 180°C. Maintain the moisture control module, if
utilized, at 90°C to remove residual water. After approximately 7
min, turn off the trap heater and open the syringe valve to stop the
gas flow through the trap. When the trap is cool, the next sample
can be analyzed.
11 5 TERMINATION OF DATA ACQUISITION — When all the sample components
have eluted from the GC, terminate MS data acquisition. Use appro-
priate data output software to display full range mass spectra and
appropriate plots of ion abundance as a function of time. If any
ion abundance exceeds the system working range, dilute the sample
524.2-24
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aliquot in the second syringe with reagent water and analyze the
diluted aliquot.
11.6 IDENTIFICATION OF ANALYTES — Identify a sample component by
comparison of its mass,spectrum (after background subtraction) to a
reference spectrum in the user-created data base. The GC retention
• time of the sample component should be within three standard
deviations of the mean retention time of the compound in the
calibration mixture.
11.6.1 In general, all ions that are present above 10% relative
abundance in the mass spectrum of the standard should be
present in the mass spectrum of the sample component and
should agree within absolute 20%. For example, if an ion has
a relative abundance of 30% in the standard spectrum, its
abundance in the sample spectrum should be in the range of 10
to 50%. Some ions, particularly the molecular ion, are of
special importance, and should be evaluated even if they are
below 10% relative abundance.
11.6.2 Identification requires expert judgment when sample compo-
nerits are not resolved chromatographically and produce mass
spectra containing ions contributed by more than one analyte.
When GC peaks obviously represent more than one sample compo-
nent (i.e., broadened peak with shoulder(s) or valley between
two or more maxima), appropriate analyte spectra and back-
ground spectra can be selected by examining plots of charac-
teristic ions for tentatively identified components. When
analytes coelute (i.e., only one GC peak is apparent), the
identification criteria can be met but each analyte spectrum
will contain extraneous ions contributed by the coeluting
compound. Because purgeable organic compounds are relatively
small molecules and produce comparatively simple mass spec-
tra, this is not a significant problem for most method
analytes.
11.6.3 Structural isomers that produce very similar mass spectra can
be explicitly identified only if they have sufficiently
different GC retention times. Acceptable resolution is
achieved if the height of the valley between two peaks is
less than 25% of the average height of the two peaks. Other-
wise, structural isomers are identified as isomeric pairs.
Two of the three isomeric xylenes and two of the three di-
chlorobenzenes are examples of structural isomers that may
not be resolved on the capillary columns. If unresolved,
these groups of isomers must be reported as isomeric pairs.
11.6.4 Methylene chloride, acetone, carbon disulfide, and other
background components appear in variable quantities in labo-
ratory and field reagent blanks, and generally cannot be
accurately measured. Subtraction of the concentration in the
blank from the concentration in the sample is not acceptable
524.2-25
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because the concentration of the background in the blank is
highly variable.
12. DATA ANALYSIS AND CALCULATIONS
12.1 Complete chromatographic resolution is not necessary for accurate
and precise measurements of analyte concentrations if unique ions
with adequate intensities are available for quantitation. Lf the
response for any analyte exceeds the linear range of the .calibration
established in Section 10, obtain and dilute a duplicate a duplicate
sample. Do not extrapolate beyond the calibration range.
12.1.1 Calculate analyte and surrogate concentrations, using the
multi-point calibration established in Section 10. Do not
use the daily calibration verification data to quantitate
analytes in samples.
C. =
(Ax)(Qis) 1000
X
(Ais) RF V
where:' Cx = concentration of analyte or surrogate in /ig/L
in the water sample.
Ax = integrated abundance of the quantitation ion
of the analyte in the sample.
Ais = integrated abundance of the quantitation ion
of the internal standard in the sample.
Qis = total quantity (in micrograms), of internal
standard added to the water sample.
V = original water sample volume in mL.
RF = mean response factor of analyte from the
initial calibration.
12.1.2 Alternatively, use the GC/MS system software or other
available proven software to compute the concentrations of
the analytes and surrogates from the linear or second order
regression curve established in Section 10. Do not use the
daily calibration verification data to quantitate analytes in
samples. . . '
12.1.3 Calculations should utilize all available digits of precis-
ion, but final reported concentrations should be rounded to
an appropriate number of significant figures (one digit of
uncertainty). Experience indicates that three significant
figures may be used for concentrations above 99 /ig/L, two
significant figures for concentrations between 1- 99 /ig/L,
and one significant figure for lower concentrations.
12.1.4 Calculate the total trihalomethane concentration by summing
the four individual trihalomethane concentrations.
13. METHOD PERFORMANCE
13.1 Single laboratory accuracy and precision data were obtained for the
method analytes using laboratory fortified blanks with analytes at
524.2-26
-------
concentrations between 0.1 and 5 pg/L. Results were obtained using
the four columns specified (Sect. 6.3.2.1) and the open split or jet
separator (Sect. 6.3.3.1), or the cryogenic interface (Sect.
6.3.3.2). These data are shown in Tables 4-8.
13.2 With these data, method detection limits were calculated using the
formula (3):
MDL = S t(n.1f1_alpha = Oi?9)
where:
V-i.i-aipha • o.99) * studen.V.s t value for the 99% confidence
level with n-1 degrees of freedom,
n = number of replicates
S = the standard deviation of the
replicate analyses.
14. POLLUTION PREVENTION
14.1 No solvents are utilized in this method except the extremely small
volumes of methanol needed to make calibration standards. The only
other chemicals used in this method are the neat materials in
preparing standards and sample preservatives. All are used in •
extremely small amounts and pose no threat to the environment.
15. WASTE MANAGEMENT
15.1 There are no waste management issues involved with this method. Due
to the nature of this method, the discarded samples are chemically
less contaminated than when they were collected.
16. REFERENCES
1. J.W. Munch, J.W. Eichelberger, "Evaluation of 48 Compounds for
Possible Inclusion in USEPA Method 524.2, Revision 3.0: Expansion of
the Method Analyte List to a Total of 83 Compounds", J. Chro. Scl
,30, 471,1992. '-
2. C. Madding, "Volatile Organic Compounds in Water by Purge and Trap
Capillary Column GC/MS," Proceedings of the Water Quality Technology
Conference, American Water Works Association, Denver, CO, December
1984.
3. J.A. Glaser, D.L. Foerst, G.D. McKee, S.A. Quave, and W.L. Budde,
"Trace Analyses for Wastewaters", Environ. Scl. Technol.. 15, 1426,
1981.
4. "Carcinogens-Working with Carcinogens," Department of Health
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77-206, August 1977.
524.2-27
-------
5. "OSHA Safety and Health Standards, General Industry," (29CFR1910),
Occupational Safety and Health Administration, OSHA 2206, (Revised,
January 1976).
6. "Safety in Academic Chemistry Laboratories," American Chemical
Society Publication, Committee on Chemical Safety, 3rd Edition,
1979.
i
7. R.F. Arrendale, R.F. Severson, and O.T. Chortyk, "Open Split Inter-
face for Capillary Gas Chromatography/Mass Spectrometry," Anal.
Chem. 1984, 56, 1533.
8. J.J. Flesch, P.S. Fair, "The Analysis of Cyanogen Chloride in Drink-
ing Water," Proceedings of Water Quality Technology Conference,
American Water Works Association, St. Louis, MO., November 14-16,
1988.
524.2-28
-------
17. TABLES. DIAGRAMS. FLOWCHARTS. AND VALIDATION DATA
TABLE 1. MOLECULAR WEIGHTS AND QUANTITATION IONS FOR METHOD ANALYTES
Primary Secondary
Quantitation Quantitation
Compound jnf Ion ions
Internal standard
Fluorobenzene 96 96 77
Surrogates
4-Bromofluorobenzene 174 95 174,176
l,2-Dichlo.robenzene-d4 150 152 115,'l50
Target Analytes
Acetone 58 43 58
Acrylonitrile 53 52 53
Ally! chloride 76 . 76 49
Benzene 78 78 77
Bromobenzene 156 156 77 153
Bromochloromethane 128 128 49'130
Bromodichloromethane 162 83 85'l27
Bromoform 250 173 17s'252
Bromomethane 94 94 ' gg
2-Butanone 72 43 57 72
n-Butylbenzene 134 91 134
sec-Butyl benzene 134 105 134
tert-Butylbenzene 134 119 91
Carbon disulfide 76 76
Carbon tetrachloride . 152 117 119
Chloroacetonitrile 75 48 75
Chlorobenzene 112 112 77 114
1-Chlorobutane . 92 56 ' 49
Chloroethane 64 64 66
Chloroform 118 83 85
Chloromethane 50 50 52
2-Chlorotoluene 126 91 126
4-Chlorotoluene 126 91 126
Dibromochloromethane 206 129 127
l,2-Dibromo-3-Chloropropane 234 75 155,157
1,2-Dibromoethane 186 107 109'l88
Dibromomethane 172 93 95^174
1,2-Dichlorobenzene 146 146 Ill'l48
1,3-Dichlorobenzene 146 146 111^148
1,4-Dichlorobenzene 146 . 146 111^148
524.2-29
-------
TABLE 1. (continued)
Compound
MW
Primary
Quantitation
Ion
Secondary
Quantitation
Ions
trans-l,4-Dich1oro-2-butene
Di chl orodi f 1 uoromethane
1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethene
ci s-1 , 2-Di chl oroethene
trans-1 , 2-Di chl oroethene
1 , 2-Di chl oropropane
1,3-Dichloropropane
2, 2-Dichl oropropane
1 , 1-Di chl oropropene
1,1-Dichloropropanone
ci s-1 ,3-di chl oropropene
trans-1 , 3-di chl oropropene
Di ethyl ether
Ethyl benzene
Ethyl methacryl ate
Hexachl orobutadi ene
Hexachloroethane
2-Hexanone
Isopropyl benzene
4-Isopropyl to! uene
Methacryl onitrile
Methyl acrylate
Methyl ene chloride
Methyl iodide
Methylmethacryl ate
4-Methyl -2-pentanone
Methyl -t-butyl ether
Naphthalene
Nitrobenzene
2-Nitropropane
Pentachloroethane
Propionitrile
n-Propyl benzene
Styrene
1,1,1, 2-Tetrachl oroethane
1,1,2, 2-Tetrachl oroethane
Tetrachl oroethene
Tetrahydrofuran
Toluene
1,2,3-Trichlorobenzene
1,2, 4-Tri chl orobenzene
1,1, 1-Tri chl oroethane
1,1,2-Tri chl oroethane
124
120
98
98
96
96
96
112
112
112
110
126
110
110
74
106
114
258
234
100
120
134
67
86
84
142
100
100
88
128
123
89
200
55
120
104
166
166
164
72
92
180
180
132
132
53
85
63
62
96
96
96
63
76
77
75
43
75
75
59
91
69
225
;117
' 43
;105
119
67
55
. 84
• 142
69
43
73
128
51
46
117
54
91
104
131
83
166
71
92
180
180
97
: 83
88,75
87
65,83
98
61,63
61,98
61,98
112
78
97
110,77
83
110
110
45,73
106
99
260
119,201
58
120
134,91
52
85
86,49
127
99
58,85
57
—
77
—
119,167
—
120
78
133,119
131,85
168,129
72,42
91
182
182
99,61
97,85
524.2-30
-------
TABLE 1. (continued)
Compound
MWa
Primary
Quantitation
Ion
Secondary
Quantitation
Ions
Trichloroethene
Tri chl orof 1 uoromethane
1,2,3-Trichloropropane
1, 2, 4-Trimethyl benzene
1, 3, 5-Trimethyl benzene
Vinyl Chloride
o-Xylene
m-Xylene
p-Xylene
130
136
146
120
120
62
106
106
106
95
101
75
105
105
62
106
106
106:
130,132
.103
77
120
' 120
64
91
91 ,
91
aMonoisotopic molecular weight calculated from the atomic masses of the
isotopes with the smallest masses.
524.2-31
-------
TABLE 2. CHROMATOGRAPHIC RETENTION TIMES FOR METHOD ANALYTES
ON THREE COLUMNS WITH FOUR SETS OF CONDITIONS3
Compound
Retention
Col. lb Col. 2b
Time
Col. 2C
(min:sec)
Col. 3d
Col. 4e
Internal standard
Fluorobenzene 8:49 6:|27
Surrogates
4-Bromof1uorobenzene
1,2-Di chlorobenzene-d4
Target Analvtes
18:38 15:43
22:16 19:,08
8:14
18:57
6:44
10:35
17:56
2:01
22:13
20:47
20:17
5:40
15:'52
4:23
8:29
14:53
0:58
I
19:29
18:05
17:34
Acetone
Acrylonitrile
Ally! chloride
Benzene
Bromobenzene
Bromochloromethane
Bromodi chloromethane
Bromoform
Bromomethane
2-Butanone
n-Butylbenzene
sec-Butyl benzene
tert-Butylbenzene
Carbon Disulfide :
Carbon Tetrachloride 7:37 5:16
Chloroacetonitrile
Chlorobenzene 15:46 13:01
1-Chlorobutane
Chloroethane 2:05 1:01
Chloroform 6:24 4:48
Chloromethane 1:38 0:44
2-Chlorotoluene 19:20 16:25
4-Chlorotoluene 19:30 16:43
Cyanogen chloride (8)
Dibromochloromethane 14:23 11:51
l,2-Dibromo-3-Chloropropane 24:32 21:05
1,2-Dibromoethane 14:44 11:50
Dibromomethane 10:39 • 7:56
1,2-Dichlorobenzene 22:31 19:10
1,3-Dichlorobenzene 21:13 18:08
1,4-Dichlorobenzene 21:33 18:23
t-1,4-Dichloro-2-butene
Dichlorodifluoromethane 1:33 0:42
1,1-Dichloroethane 4:51 2:56
14:06
23:38
27:25
8:03
22:00
31:21
35:51
13:30
24:00
12:22
15:48
22:46
4:48
27:32
26:08
25:36
13:10 .
20:40
12:36
3:24
24:32
24:46
19:12
19:24
15:26
27:26
26:22
26:36
3:08
10:48
7:25
16:25
5:38
9:20
15:42
1:17
17:57
17:28
17:19
7:25
14:20
1:27
5:33
0:58
16:44
16:49
1:03
12:48
18:02
13:36
9:05
17:47
17:28
17r38
0:53
4:02
16:14
17:49
16t58
21:32
31:52
20:20
, 23:36
30:32
12:26
19:41
35:41
34:04
33:26
16:30
21:11
23:51
28:26
21:00
20:27
9:11
32:21
32:38
26:57
38:20
27:19
23:22
35:55
34:31
34:45
31:44
7:16
18:46
524.2-32
-------
TABLE 2. (continued)
Compound
1,2-Dichloroethane
1,1-Dichloroethene
cis-l,2-Dichlproethene
trans- 1 , 2-Di chl oroethene
1 , 2-Di chl oropropane
1,3-Di chl oropropane
2 , 2-Di chl oropropane
1 , 1-Di chl oropropanone
1,1-Dichloropropene
cis-l,3-dichloroprbpene
trans-1 , 3-di chl oropropene
Diethyl ether
Ethyl benzene
Ethyl Methacrylate
Hexachlorobutadiene
Hexachloroethane
Hexanone
Isopropyl benzene
4-Isopropyltol uene
Methacrylonitrile
Methyl acryl ate
Methylene Chloride
Methyl Iodide
Methyl methacryl ate
4-Methyl-2-pentanone
Methyl -t-butyl ether
Naphthalene
Nitrobenzene
2-Nitropropane
Pentachl oroethane
Propionitrile
n-Propyl benzene
Styrene
1,1,1, 2-Tetrachl oroethane
1 , 1 , 2 , 2-Tetrachl oroethane
Tetrachl oroethene
Tetrahydrofuran
Toluene
1,2, 3-Tri chl orobenzene
1,2, 4-Tri chl orobenzene
1,1, 1-Tri chl oroethane
1,1, 2-Tri chl oroethane
Trichloroethene
Tri chl orof 1 uoromethane
1,2, 3-Tri chl oropropane
1,2, 4-Tri methyl benzene
Retention
Col. lb Col. 2b
8:24
2:53
6:11
3:59
10:05
14:02
6:01
7:49
11.58
13.46
15:59
26:59
18:04
21:12
3:36
27:10
19:04
17:19
15:56
18:43
13:44
12:26
27:47
26:33
7:16
13:25
9:35
2:16
19:01
20:20
5:50
1:34
3:54
2:22
7:40
11:19
3:48
5:17
13:23
23:41
15:28
18:31
2:04
23:31
16:25
14:36
13:20
16:21
11:09
10:00
24:11
23:05
4:50
11:03
7:16
1:11
16:14
17:42
Time
Col . 2°
13:38
7:50
11:56
9:54
15:12
18:42
11:52
13:06
16:42
17:54
21:00
32:04
23:18 .
26:30
9:16
32:12
24:20
22:24
20:52
24:04
18:36
17:24
32:58
31:30
12:50
18:18
14:48
6:12
24:08
31:30
(min:sec}
Col. 3a
7:00
2:20
5:04
3:32
8:56
12:29
5:19
7:10
14:44
19:14
16:25
17:38
2:40
19:04
16:49
15:47
14:44
15:47
13:12
11:31
19:14
18:50
6:46
11:59
9:01
1:46
16:16
17:19
Col. 4e
21:31
16:01
19:53
17:54
23:08
26:23
19:54
24:52
21:08
24:24
25:33
15:31
28:37
25:35
42:03
36:45
26:23
30:52
34:27
20:15
20:02
17:18
16:21
23:08
24:38
17:56
42:29
39:02
23:58
33:33
19:58
32:00
29:57
28:35
31:35
26:27
20:26
25:13
43:31
41:26
20:51
25:59
22:42
14:18
31:47
33:33
524-.2-33
-------
TABLE 2. (continued)
Compound
Retention
Col. lb Col. 2b
Time (minisec)
Col. 2C Col. 3d
Col. 4e
1,3, 5-Tri methyl benzene
Vinyl chloride
o-Xyl ene
m-Xyl ene
p-Xyl ene
19:28
1:43
17:07
16:10
16:07
•16:54 .
0:47
14:31
13:41
•13:41
24:50
3:56
22:16
21:22
21:18
16:59
1:02
15:47
15:18
15:18
32:26
10:22
29:56
28:53
28:53
"Columns 1-4 are those given in Sect. 6.3.2.1; retention times were measured
from the beginning of thermal desorption from the trap (columns 1-2, and 4) or
from the beginning of thermal release from the cryogenic interface (column 3).
bGC conditions given in Sect. 11.3.1.
CGC conditions given in Sect. 11.3.2.
dGC conditions given in Sect. 11.3.3.
CGC conditions given in Sect. 11.3.4.
524.2-34
-------
I
TABLE 3. ION ABUNDANCE CRITERIA FOR 4-BROMOFLUOROBENZENE (BFB)
Mass
Relative Abundance Criteria
50
75
95
96
173
174
175
176
177
15 to 40% of mass 95
30 to 80% of mass 95
Base Peak, 100% Relative Abundance
5 to 9% of mass 95
< 2% of mass 174
> 50% of mass 95
5 to 9% of mass 174
> 95% but < 101% of mass 174
5 to 9% of mass 176
524.2-35
-------
TABLE 4. ACCURACY AND PRECISION DATA FROM 16-31 DETERMINATIONS OF THE METHOD
ANALYTES IN REAGENT WATER USING WIDE BORE CAPILLARY COLUMN la
Compound
Benzene
Bromobenzene
Bromochl oromethane
Bromodi chl oromethane
Bromoform
Brqmomethane
n-Butyl benzene
sec-Butyl benzene
tert-Butyl benzene
Carbon tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chl oromethane
2-Chlorotoluene
4-Chlorotoluene
Dibromochl oromethane
1 , 2-Dibromo-3-chl oropropane
1,2-Dibromoethane
Dibromomethane
1 , 2-Di chl orobenzene
1,3-Di chlorobenzene
1 , 4-Di chl orobenzene
Di chl orodi f 1 uoromethane
1,1-Dichloroethane
1, 2-Di chloroethane
1,1-Dichloroethene
cis-1,2 Dichloroethene
trans-1 , 2-Di chl oroethene
1 , 2-Di chl oropropane
1 , 3-Di chl oropropane
2 , 2-Di chl oropropane
1,1-Dichloropropene
ci s-1 , 2-Di chl oropropene
trans-1 , 2-Di chl oropropene
Ethyl benzene
Hexachlorobutadiene
Isopropyl benzene
4-Isopropyl tol uene
Methyl ene chloride
Naphthalene
n-Propyl benzene
Styrene
True
Cone. A
Range (%
jjja/n
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.1-10
.1-10
.5-10
.1-10
.5-10
.5-10
.5-10
.5-10
.5-10
.5-10
.1-10
.5-10
.5-10
.5-10
.1-10
.1-10
.1-10
.5-10
.5-10
.5-10
.1-10
.5-10
.2-20
.5-10
.5-10
.1-10
.1-10
.5-10
.1-10
.1-10
.1-10
.5-10
.5-10
.1-10
.5-10
.5-10
.1-10
.1-10
.1-100
.1-10
.1-100
Mean
ccuracy
of True
Value)
97
100
90
95
101
95
100
100
102
84
98
89
90
93
90
99
92
83
102
100
93
99
103
. 90
96
95
94
101
93
97
96
86
98
99
100
101
99
95
104
100
102
Rel.
Std.
Dev.
m
5.
5.
6.
6.
6.
8.
7.
7.
7.
8.
5.
9.
6.
8.
6.
8.
7.
19.
3.
5.
6.
, 6.
6.
7.
5.
5.
6.
6.
5.
6.
6.
16.
8.
8.
6.
7.
6.
5.
8.
5.
7.
7
5
4
1
3
2
6
6
3
8
9
0
1
9
2
3
0
9
9
6
2
9,
4
7
3
4
7
7
6
1
0
9
9
6
8
6
7
3
2
8
2
Method
Det.
Limitb
(ua/L)
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
04
03
04
08
12
11
11
13
14
21
04
10
03
13
04
06
05
26
06
24
03
12
03
10
04
06
12
12
06
04
04
35
10
06
11
15
12
03
04
04
04
524.2-36
-------
TABLE 4. (Continued)
Compound
1,1,1, 2-Tetrachl oroethane
1 , 1 , 2, 2-Tetrachl oroethane
Tetrachl oroethene
Tol uene
1,, 2 ,3-Tri chl orobenzene
1,2,4-Trichlorobenzene
1 , 1 , 1-Tri chl oroethane
1,1, 2-Tri chl oroethane
Trichloroethene
Tri chl orof 1 uoromethane
1,2,3-Trichloropropane
1, 2, 4-Tri methyl benzene
1, 3, 5-Tri methyl benzene
Vinyl chloride
o-Xylene
m-Xylene
p-Xylene
True
Cone.
Range
(UQ/L)
0.5-10
0.1-10
0.5-10
0.5-10
0.5-10
0.5-10
0.5-10
0.5-10
0.5-10
0.5-10
0.5-10
0.5-10
0.5-10
0.5-10
0.1-31
0.1-10
0.5-10
Mean
Accuracy
(% of True
Value)
90
91
89
102
109
108
98
104
. 90
89
108
99
92
98
103
97
104
. Rel.
Std.
Dev.
m
6.8
6.3
6.8
8.0
8.6
8.3
8.1
7.3
7.3
8.1
14.4
8.1
7.4
6.7
7.2
6.5
7.7
Method
Det.
Limit",
(•im/L)
0.05
0.04
0.14
0.11 '
0.03
0.04
0.08 '
0.10
0.19
0.08
0.32
0.13
0.05
0.17
0.1 1/.
0.05 '
0.13
aData obtained by using column 1 with a jet separator interface and',a
quadrupole mass spectrometer (Sect. 11.3.1) with analytes divided among
three solutions.
bReplicate samples at the lowest concentration listed in column 2 of this
table were analyzed. These results were used to calculate MDLs.
524.2-37
-------
TABLE 6. ACCURACY AND PRECISION DA^A FROM SEVEN DETERMINATIONS
OF THE METHOD ANALYTES IN REAGENT WATER USING WIDE BORE
CAPILLARY COLUMN 2a
Compound
Mean Accuracy ,
(% of True
Value, RSD
No.b 2 LLQ/L Cone.) (%)
Mean Accuracy
(% of True
Value,
0.2 itq/L Cone.)
RSD
Internal Standard
Fluorobenzene
Surrogates
4-Bromof1uorobenzene
1,2-Di chlorobenzene-d4
Target Analvtes
Benzene
Bromobenzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
n-Butylbenzene
sec-Butyl benzene
tert-Butylbenzene
Carbon tetrachloride
Chlorobenzene
Chloroethane0
Chloroform
Chloromethane
2-Chlorotoluene
4-Chlorotoluene
Di bromochloromethane
1,2-Di bromo-3-chloropropanec
l,2-Dibromoethanec
Dibromomethane
1,2-Di chlorobenzene
1,3-Di chlorobenzene
1,4-Dichlorobenzene
Di chlorodi f1uoromethane
1,1-Di chloroethane
1,2-Di chloroethane
1,1-Dichloroethene
cis-1,2-Dichloroethene
trans-1,2-Di chloroethene
2
3
98
97
37
38
4
5
6
7
39
40
41
8
42
9
10
43
44
11
97
102
99
96
89
55
89
102
101
84
104
97
110
91
89
95
1.8
3.2
4.4
3.0
5.2
1.8
2.4
27.
4.8
3.5
4.5
3.2
3.1
2.0
5.0
2.4
2.0
2.7
13
45
46
47
14
15
16
17
18
19
99 2.1
93 2.7
100
4.0
98 4.1
38
25.
97 2.3
102 ! 3.8
90
100
2.2
3.4
92 2.1
96
95
113
101
102
100
90
52
87
100
100
92
103
95
d
108
108
100
95
94
87
94
d
85
100
87
89
85
1.3
1.7
1.8
1..?
2.9
1.8
2.2
6.7
2.3
2.8
2.9
2.6
1.6
2.1
3.1
4.4
3.0
2.2
5.1
2.3
2.8
3.6
2.1
3.8
2.9
2.3
524.2-40
-------
TABLE 6. (Continued)
Compound
1,2-Dichloropropane
1,3-Dichloropropane
2,2-Dichloropropanec
l,l-Dichloropropenec
cis-l,3-Dichloropropenec
trans-l,3-Dichloropropene
Ethyl benzene
Hexachl orobutadi ene
Isopropyl benzene
4-Isopropyltoluene
Methylene chloride
Naphthalene
n-Propyl benzene
Styrene
1,1,1, 2-Tetrachl oroethane
1,1,2, 2-Tetrachl oroethane
Tetrachl oroethene
Toluene
1,2,3-Trichlorobenzene
1,2,4-Trichlorobenzene
1 , 1 , 1-Tri chl oroethane
1,1,2-Trichl oroethane
Trichloroethene
Tri chl orof 1 uoromethane
1,2,3-Trichloropropane
1, 2, 4-Tri methyl benzene
1,3, 5-Tri methyl benzene
Vinyl chloride
o-Xylene
m-Xylene
p-Xylene
Mean Accuracy
(% of True
Value, RSD
No.b 2 UQ/l Cone.) (%)
20
21
25
48
26
49
50
27
51
52
53
28
29
30
54
55
56
31
32
33
34
35
57
58
36
59
60
61
102
92
96
96
91
103
95
e
93
102
95
99
101
97
105
90
92
94'
107
99
81
97
93
88
104
97
f
98
2.2
3.7
1.7
9.1
5.3
3.2
3.6
7.6
4.9
4.4
2.7
4.6
4.5
2.8
5.7
5.2
3.9
3.4
2.9
4.6
3.9
3.1
2.4
3.5
1.8
2.3
Mean Accuracy
(% of True
Value, RSD
0.2 uq/L Cone.) (%)
103
93
99
100
88
101
95
e
78
97
104
95
84
92
126
78
83
94
109
106
48
91
106
97
115
98
f
103
2.9
3.2
2.1
4.0
2.4
2.1
3.1
8.3
2.1
3.1
3.8
3.6
3.3
1.7
2.9
5.9
2.5
2.8
2.5
13.
2.8
2.2
"3.2
14.
1.7
1.4
aData obtained using column 2 with the open split interface and an ion
trap mass spectrometer (Sect. 11.3.2) with all method analytes in the same
reagent water solution.
Designation in Figures 1 and 2.
cNot measured; authentic standards were not available.
dNot found at 0.2 /jg/L.
eNot measured; methylene chloride was in the laboratory reagent blank.
fm-xylene coelutes with and cannot be distinguished from its isomer p-xylene,
No 61.
524.2-41
-------
TABLE 7. ACCURACY AND PRECISION DATA FROM SEVEN DETERMINATIONS
OF METHOD ANALYTES IN REAGENT WATER USING WIDE BORE
CAPILLARY COLUMN NUMBER 4a
Compound
Acetone
Acrylonitrile
Ally! chloride
2-Butanone
Carbon disulfide
Chloroacetonitrile
1-Chlorobutane
t-Dichloro-2-butene
1, 1-Dichloropropanone
c-l,3-Dichloropropene
t-l,3-Dichloropropene
Di ethyl ether
Ethyl methacrylate
Hexachloroethane
2-Hexanone
Methacrylonitrile
Methyl acryl ate
Methyl iodide
Methyl methacryl ate
4-Methyl -2-pentanone
Methyl -tert-butyl ether
Nitrobenzene
2-Nitropropane
Pentachl oroethane
Propionitrile
Tetrahydrofuran
True
Cone.
(fig/L)
1.0
1.0
1.0
2.0
0.20
1.0
1.0
1.0
5.0
0.20
0.10
1.0
0.20
0.20
1.0
1.0
1.0
0.20
1.0
0.40
0.40
2.0
1.0
0.20
1.0
5.0
Mean
Cone.
Detected
(ug/L)
1.6
0.81
0.90
2.7
. 0.19
0.83
:0.87
1.3
4.2
0.20
0.11
0.92
;0.23
0.18
1.1
0.92
1.2
0.19
1.0
0.56
b.52
2.1
0.83
0.23
0.87
3.9
Rel.
Std.
Dev.
5.7
8.7
4.7
5.6
15
4.7
6.6
8.7
7.7
3.1
14
9.5
3.9
10
12
4.2
12
3.1
13
9.7
5.6
18
6.2
20
5.3
13
Method
Detect.
Limit
(M9/L)
0.28
0.22
0.13
0.48
0.093
0.12
0.18
0.36
1.0
0.020
0.048
0.28
0.028
0.057
0.39
0.12
0.45
0.019
0.43
0.17
0.090
1.2
0.16
0.14
0.14
1.6
Data obtained using column 4 with the open split interface and an ion trap
mass spectrometer.
524.2-42
-------
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-------
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524.2-45
-------
PACKING PftOCffiUJE
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FIGURE 2. TRAP PACKINGS AND CONSTRUCTION TO INCLUDE
OESORB CAPABILITY
524.2-46
-------
't
1
3
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-------
i
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524.2-48
-------
METHOD 525.2
DETERMINATION OF ORGANIC COMPOUNDS IN DRINKING WATER
BY LIQUID-SOLID EXTRACTION AND CAPILLARY COLUMN GAS
CHROMATOGRAPHY/MASS SPECTROMETRY
Revision 1.1
J.W. Eichelberger, T.D. Behymer, W.L. Budde - Method 525,
Revision 1.0, 2.0, 2.1 (1988)
J.W. Eichelberger, T.D. Behymer, and W.L. Budde - Method 525.1
Revision 2.2 (July 1991)
J.W. Eichelberger, J.W. Munch, and J.A. Shoemaker
Method 525.2 Revision 1.0 (February, 1994)
J.W. Munch - Method 525.2, Revision 2.0 (1995)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
525.2-1
-------
METHOD 525.2
DETERMINATION OF ORGANIC COMPOUNDS IN DRINKING WATER
BY LIQUID-SOLID EXTRACTION AND CAPILLARY COLUMN
GAS CHROMATOGRAPHY/MASS SPECTROMETRY
1. SCOPE AND APPLICATION
1.1 This is a general purpose method that provides procedures for
determination of organic compounds in finished drinking water,
source water, or drinking water in any treatment stage. The method
is applicable to a wide range of organic compounds that are
efficiently partitioned from the water sample onto a C18 organic
phase chemically bonded to a solid matrix in a disk or cartridge,
and sufficiently volatile and thermally stable for gas chromatog-
raphy. Single-laboratory accuracy and precision data have been
determined with two instrument systems using both disks and car-
tridges for most of the following compounds:
Analvte
Acenaphthylene
Alachlor
Aldrin
Ametryn
Anthracene
Atraton
Atrazine
Benz[a]anthracene
Benzo[b]fluoranthene
Benzo[k]fluoranthene
Benzo[a]pyrene
Benzo[g,h,i]perylene
Bromacil
Butachlor
Butyl ate
Butyl benzylphthalate
Carboxin2
Chlordane components
Alpha-chlorda.ne
Gamma-chlordane
Trans nonachlor
Chlorneb
Chlorobenzilate
Chlorpropham
Chlorothalonil
Chlorpyrifos
2-Chlorobiphenyl
MW
152
269
362
227
178
211
215
228
252
252
252
276
260
$11
217
312
235
406
406
440
206
324
213
264
349
188
Chemical Abstracts Service
Registry Number
208
15972
309
834
120
1610
1912
56
205
207
50
191-
314-
23184-
2008-
85-
5234-
5103-
5103-
39765-
2675-
510-
101-
1897-
2921-
2051-
•96-8
-60-8 '
-00-2
-12-8
-12-7
-17-9
-24-9
-55-3
-82-3
-08-9
-32-8
-24-2
-40-9
-66-9
-41-5
-68-7
-68-4
71-9
74-2
80-5
77-6
15-6
21-3
45-6
88-2
60-7
525.2-2
-------
Chrysene 228
Cyanazine 240
Cycloate 215
Dacthal(DCPA) 330
ODD, 4,4'-. 318
DDE, 4,4'- 316
DDT, 4,4'- 352
Diazinon 304
Dibenz[a,h]anthracene 278
Di-n-butylphthalate 278
2,3-Dichlorobiphenyl 222
Dichlorvos 220
Dieldrin 378
Diethylphthalate 222
Di(2-ethylhexyl)adipate 370
Di(2-ethylhexyl,)phthalate 390
DimethylIphthalate 194
2,4-Dinitrotoluene 182
2,6-Dinitrotoluene 182
Diphenamid 239
Disulfoton2 274
Disulfoton sulfoxide2 • 290
Disulfoton sulfone 306
Endosulfan I 404
Endosulfan II 404
Endosulfan sulfate 420
Endrin 373
Endrin aldehyde 378
EPIC 189
Ethoprop 242
Etridiazole 246
Fenamiphos2 303
Fenarimol . 330
Fluorene 166
Fl undone 328
Heptachlor 370
Heptachlor epoxide 386
2,2',3,3',4,4',6-Heptachloro-
biphenyl 392
Hexachlorobenzene 282
2,2',4,4',5,6'-Hexachloro-
biphenyl 353
Hexachlorocyclohexane, alpha 288
Hexachlorocyclohexane, beta 288
Hexachlorocyclohexane, delta 288
Hexachlorocyclopentadiene 270
Hexazinone 252
Indeno[l,2,3,c,d]pyrene 276
Isophorone 133
Lindane 288
Merphos 298
Methoxychlor 344
218
21725
1134
1861
72
72
50
333
53
84-
16605-
62-
60-
84-
103-
117-
131-
121-
606-
957-
298-
2497-
2497-
959-
33213-
1031-
72-
7421-
759-
13194-
2593-
22224-
6016,8-
86
59756
76
1024
01-9
-46-2
-23-2
-32-1
-54-8
-55-9
-29-3
-41-5
-70-3
-74-2
-91-7
-73-7
-57-1
-66-2
-23-1
-81-7
-11-3
-14-2
-20-2
-51-7
-04-4
-07-6
-06-5
-98-8
-65-9
-07-8
-20-8
-93-4
•94-4
•48-4
15-9
92-6
88-9
73-7
60-4
44-8
57-3
52663-71-5
118-74-1
60145-
319-
319-
319-
77-
51235-
193-
78-
58-
150-
72-
-22-4
•84-6
•85-7
•86-8
•47-4
04-2
39-5
59-1
89-9
50-5
43-5
525.2-3
-------
Methyl paraoxon
Metolachlor
Metribuzin
Mevinphos
MGK 264
Molinate
Napropamide
Norflurazon
2,2',3,3',4,5',6,6'-Octa-
chlorobiphenyl
Pebulate
2,2',3',4,6-Pentachloro-
biphenyl
Pentachlorophenol
Phenanthrene
Permethrin, cis-
Permethrin, trans
Prometon
Prometryn
Pronamide
Propachlor
Propazine
Pyrene
Simazine
Simetryn
Stirofos
Tebuthiuron
Terbacil
Terbufos2
Terbutryn
2,2' ,4,4'-Tetrach1orobiphenyl
Toxaphene
Triademefon
2,4,5-Trichlorobiphenyl
Tricyclazole
Trifluralin
Vernolate
Aroclor 1016
Aroclor 1221
Aroclor 1232
Aroclor 1242
Aroclor 1248
Aroclor 1254
Aroclor 1260
247
283
214
224
275
187
271
303
426
203
324
264
178
390
390
225
241
255
211
229
202
201
213
364
228
216
288
241
290
293
256
189
335
203
;
950-35-6
51218-45-2
21087-64-9
7786-34-7
113-48-4
2212-67-1
15299-99-7
27314-13-2
40186-71-8
1114-71-2
60233-25-2
87-86-5
85-01-8
54774-45-7
51877-74-8
1610-18-0
7287-19-6
23950-58-5
1918-16-7
139-40-2
129-00-0
122-34-9
1014-70-6
22248-79-9
34014-18-1
5902-51-2
13071-79-9
886-50-0
2437-79-8
8001-35-2
43121-43-3
15862-07-4
41814-78-2
1582-09-8
1929-77-7
12674-11-2
11104-28-2
11141-16-5
53469-21-9
12672-29-6
11097-69-1
11096-82-5
^onoisotopic molecular weight calculated from the atomic masses of
the isotopes with the smallest masses.
525.2-4
-------
Only qualitative identification of these analytes is possible
because of their instability in aqueous matrices. Merphos, car-
boxin, disulfoton, and disulfoton sulfoxide showed instability
within 1 h of fortification. Diazinon, fenamiphos, and terbufos
showed significant losses within 7 days under the sample storage
conditions specified in this method;
Attempting to determine all of the above analytes in all samples is
not practical and not necessary in most cases. If all the analytes
must be determined, multiple calibration mixtures will be required.
1.2 Method detection limit (MDL) is defined as the statistically calcu-
lated minimum amount that can be measured with 99% confidence that
the reported value is greater than zero (1). The MDL is compound
dependent and is particularly dependent on extraction efficiency and
sample matrix. MDLs for all method analytes are listed in Tables 3
through 6. The concentration calibration range demonstrated in this
method is 0.1 //g/L to 10 ng/L for most analytes.
2. SUMMARY OF METHOD
Organic compound analytes, internal standards, and surrogates are
extracted from a water sample by passing 1 L of sample water through a
cartridge or disk containing a solid matrix with a chemically bonded C18
organic phase (liquid-solid extraction, LSE). The organic compounds are
eluted from the LSE cartridge or disk with small quantities of ethyl
acetate followed by methylene chloride, and this extract is concentrated
further by evaporation of some of the solvent. The sample components are
separated, identified, and measured by injecting an aliquot of the
concentrated extract into a high resolution fused silica capillary column
of a gas chromatography/mass spectrometry (GC/MS) system. Compounds
eluting from the GC column are identified by comparing their measured
mass spectra and retention times to reference spectra and retention times
in a data base. Reference spectra and retention times for analytes are
obtained by the measurement of calibration standards under the same
conditions used for samples. The concentration of each identified
component is measured by relating the MS response of the quantitation ion
produced by that compound to the MS response of the quantitation ion
produced by a compound that is used as an internal standard. Surrogate
analytes, whose concentrations are known in every sample, are measured
with the same internal standard calibration procedure.
3. DEFINITIONS
3.1 INTERNAL STANDARD (IS) — A pure analyte(s) added to a sample,
extract, or standard solution in known amount(s) and used to measure
the relative responses of other method analytes and surrogates that
are components of the same solution. The internal standard must be
an analyte that is not a sample component.
3.2 SURROGATE ANALYTE (SA) - A pure analyte(s), which is extremely
unlikely to be found in any sample, and which is added to a sample
525.2-5
-------
aliquot in known amount(s) before extraction or other processing,
and is measured with the same procedures used to measure other
sample components. The purpose of the SA is to monitor method
performance with each sample.
3.3 LABORATORY DUPLICATES (LD1 and LD2) — Two aliquots of the same
sample taken in the laboratory and analyzed separately with iden-
tical procedures. Analyses of LD1 and LD2 indicate precision
associated with laboratory procedures, but not with sample collec-
tion, preservation, or storage procedures.
3.4 FIELD DUPLICATES (FD1 and FD2) — TWO separate samples collected at
the same time and place under identical circumstances, and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation, and storage, as well as with
laboratory procedures.
i I,
3.5 LABORATORY REAGENT BLANK (LRB) — An aliquot of reagent water or
other blank matrix that is treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents, internal
standards, and surrogates that are used with other samples. The LRB
is used to determine if method analytes or other interferences are
present in the laboratory environment, the reagents, or the
apparatus.
3.6 FIELD REAGENT BLANK (FRB) — An aliquot of reagent water or other
blank matrix that is placed in a sample container in the laboratory
and treated as a sample in all respects, including shipment to the
sampling site, exposure to sampling site conditions, storage,
preservation, and all analytical procedures. The purpose of the FRB
is to determine if method analytes or other interferences are
present in the freld environment.
3.7 INSTRUMENT PERFORMANCE CHECK SOLUTION (IPC) — A solution of one or
more method analytes, surrogates, internal standards, or other test
substances used to evaluate the performance of the instrument system
with respect to a defined set of method criteria.
3.8 LABORATORY FORTIFIED BLANK (LFB) --- An aliquot of reagent water or
other blank matrix to which known quantities of the method analytes
are added in the laboratory. The LFB is analyzed exactly like a
sample, and its purpose is to determine whether the methodology is
in control, and whether the laboratory is capable of making accurate
and precise measurements.
3.9 LABORATORY FORTIFIED SAMPLE MATRIX (LFM> — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
525.2-6
-------
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
3.10 STOCK STANDARD SOLUTION (SSS) - A concentrated solution containing
one or more method analytes prepared in the laboratory using assayed
reference materials or purchased from a reputable commercial source.
3.11 PRIMARY DILUTION STANDARD SOLUTION (PDS) — A solution of several
analytes prepared in the laboratory from stock standard solutions
and diluted as needed to prepare calibration solutions and other
needed analyte solutions.
3.12 CALIBRATION STANDARD (CAL) -- A solution prepared from the primary
dilution standard solution or stock standard solutions and the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration.
3.13 QUALITY CONTROL SAMPLE (QCS) - A solution of method analytes of
known concentrations which is used to fortify an aliquot of LRB or
sample matrix. The QCS is obtained from a source external to the
laboratory and different from the source of calibration standards.
It is used to check laboratory performance with externally prepared
test materials.
4. INTERFERENCES
4.1 During analysis, major contaminant sources are reagents and liquid-
solid extraction devices. Analyses of field and laboratory reagent
blanks provide information about the presence of contaminants.
4.2 Interfering contamination may occur when a sample containing low
concentrations of compounds is analyzed immediately after a sample
containing relatively high concentrations of compounds. Syringes
and splitless injection port liners must be cleaned carefully or
replaced as needed. After analysis of a sample containing high
concentrations of compounds, a laboratory reagent blank should be
analyzed to ensure that accurate values are obtained for the next
sample.
5. SAFETY
5.1 The toxicity or carcinogenicity of chemicals used in this method has
not been precisely defined; each chemical should be treated as a
potential health hazard, and exposure to these chemicals should be
mlnoo,!«ed- Fach 1ab°ratory is responsible for maintaining awareness
of OSHA regulations regarding safe handling of chemicals used in
.this method. Additional references to laboratory safety are cited
5.2 Some method analytes have been tentatively classified as known or
suspected human or mammalian carcinogens. Pure standard materials
and stock standard solutions of these compounds should be handled
with suitable protection to skin, eye's, etc.
525.2-7
-------
6. EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.)
6.1
6.2
All glassware must be meticulously cleaned. This may be
accomplished by washing with detergent and water, rinsing with
water, distilled water, or solvents, air-drying, and heating (where
appropriate) in a muffle furnace. Volumetric glassware should never
be heated to the temperatures obtained in a muffle furnace.
Sample containers. 1-L or 1-qt amber glass bottles fitted with
Teflon-lined screw caps. Amber bottles are highly recommended since
some of the method analytes are very sensitive to light and are
oxidized or decomposed upon exposure.
6.3 Volumetric flasks, various sizes.
s
6.4 Laboratory or aspirator vacuum system. Sufficient capacity to
maintain a minimum vacuum of approximately 13 cm (5 in.) of mercury
for cartridges. A greater vacuum (66 cm [26 in.] of mercury) may be
used with disks.
6.5 Micro syringes, various sizes.
6.6 Vials. Various sizes of amber vials with Teflon-lined screw caps.
6.7 Drying column. The drying tube should contain about 5 to 7 grams of
anhydrous sodium sulfate to prohibit residual water from
contaminating the extract. Any small tube may be used, such as a
syringe barrel, a glass dropper, etc. as long as no sodium sulfate
passes through the column into the extract.
6.8 Analytical balance. Capable of weighing 0.0001 g accurately.
6 9 Fused silica capillary gas chromatography column. Any capillary
column that provides adequate resolution,' capacity, accuracy, and
precision (Sect. 10) can be used. Medium polar, low bleed columns
are recommended for use with this method to provide adequate
chromatography and minimize column bleed. A 30 m X 0.25 mm id fused
silica capillary column coated with a 0.25 /zm bonded film of
polyphenylmethylsilicone (J&W DB-5.MS) was used to develop this
method. Any column which provides analyte separations equivalent to
or better than this column may be used.
6.10 Gas chromatograph/mass spectrometer/data system (GC/MS/DS).
6 10.1 The GC must be capable of temperature programming and be
equipped for splitless/split injection. On-column capillary
injection is acceptable if all the quality control
specifications in Sect. 9 and Sect. 10 are met. The
injection tube liner should be quartz and about 3 mm in
diameter. The injection system must not allow the analytes
525.2-8
-------
to contact hot stainless steel or other metal surfaces that
promote decomposition.
6.10.2 The GC/MS interface should allow the capillary column or
transfer line exit to be placed w.ithin a few mm of the ion
source. Other interfaces, for example the open split inter-
face, are acceptable as long as the system has adequate
sensitivity (see Sect. 10 for calibration requirements).
6.10.3 The mass spectrometer must be capable of electron
ionization at a nominal electron energy of 70 eV to produce
positive ions. The spectrometer must be capable of scanning
at a minimum from 45 to 450 amu with a complete scan cycle
time (including scan overhead) of 1.0 sec or less. (Scan
cycle time = total MS data acquisition time in sec divided by
number of scans in the chromatogram). The spectrometer must
produce a mass spectrum that meets all criteria in Table 1
when an injection of approximately 5 ng of DFTPP is
introduced into the GC. An average spectrum across the DFTPP
GC peak may be used to test instrument performance. The scan
time should be set so that all analytes have a minimum of 5
scans across the chromatographic peak.
6.10.4 An interfaced data system is required to acquire, store,
reduce, and output mass spectral data. The computer software
must have the capability of processing stored GC/MS data by
recognizing a GC peak within any given retention time window,
comparing the mass spectrum from the GC peak with spectral
data in a user-created data base, and generating a list of
tentatively identified compounds with their retention times
and scan numbers. The software must also allow integration
of the ion abundance of any specific ion between specified
time or scan number limits, calculation of response factors
as defined in Sect. 10.2.6 (or construction of a linear
regression calibration curve), calculation of response factor
statistics (mean and standard deviation), and calculation of
concentrations of analytes using either the calibration curve
or the equation in Sect. 12.
6.11 Standard Filter Apparatus, ALL GLASS OR TEFLON LINED. These should
be used to carry out disk extractions when no automatic system or
manifold is utilized.
6.12 A manifold system or an automatic or robotic commercially available
sample preparation system designed for either cartridges or disks
may be utilized in this method if all quality control requirements
discussed in Sect. 9 are met.
7. REAGENTS AND STANDARDS
7.1 Helium carrier gas, as contaminant free as possible.
525,2-9
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7.2 Liquid-solid extraction (LSE) cartridges. Cartridges are inert
non-leaching plastic, for example polypropylene, or glass, and must
not contain plasticizers, such as phthalate esters or adipates, that
leach into the ethyl acetate and methylene chloride eluant. The
cartridges are packed with about 1 gram of silica, or other inert
inorganic support, whose surface is modified by chemically bonded
octadecyl (C18) groups. The packing must have a narrow size
distribution and must not leach organic compounds into the eluting
solvent. One liter of water should pass through the cartridge in
about 2 h with the assistance of a slight vacuum of about 13 cm (5
in.) of mercury. Sect. 9 provides criteria for acceptable LSE
cartridges which are available from several commercial suppliers.
The extraction disks contain octadecyl bonded silica uniformly
enmeshed in an inert matrix. The disks used to generate the data in
this method were 47 mm in diameter and 0.5 mm in thickness. Other
disk sizes are acceptable and larger disks may be used for special
problems or when sample compositing "is carried out. As with
cartridges, the disks should not contain any organic compounds,
either from the matrix or the bonded silica, which will leach into .
the ethyl acetate and methylene chloride eluant. One liter of
reagent water should pass through thja disks in 5-20 min using a
vacuum of about 66 cm (26 in.) of mercury. Sect. 9 provides
criteria for acceptable LSE disks wh[ich are available commercially.
7.3 Solvents
7.3.1 Methylene chloride, ethyl acetate, acetone, toluene and
methanol. High purity pesticjide quality or equivalent.
7.3.2 Reagent water. Water in which an interference is not
observed at the method detection5 limit of the compound of
interest. Prepare reagent water by passing tap water through
a filter bed containing about 0.5 kg of activated carbon or
by using a water purification system. Store in clean,
narrow-mouth bottles with TefTon-lined septa and screw caps.
7.4 Hydrochloric acid. 6N.
7.5 Sodium sulfate, anhydrous. (Soxhlet extracted with methylene
chloride for a minimum of 4 h or heated to 400°C for 2 h in a muffle
furnace.) .
7.6 Stock standard solutions. Individual solutions of surrogates,
internal standards, and analytes, or mixtures of analytes, may-be
purchased from commercial suppliers or prepared from pure materials.
To prepare, add 10 mg (weighed on an analytical balance to 0.1 mg)
of the pure material to 1.9 mL of methanol, ethyl acetate, or
acetone in a 2-mL volumetric flask, dilute to the mark, and transfer
the solution to an amber glass vial. If the analytical standard is
availab-le only in quantities smaller than 10 mg, reduce the volume
of solvent accordingly. Some polycyclic aromatic hydrocarbons are
525.2-10 :
-------
I
not soluble in methanol, ethyl acetate, or acetone, and their stock
standard solutions are prepared in toluene. Methylene chloride
should be avoided as a solvent for standards because its high vapor
pressure leads to rapid evaporation and concentration changes
Methanol, ethyl acetate, and acetone are not as volatile as
methylene chloride, but their solutions must also be handled with
care to avoid evaporation. If compound purity is confirmed by the
supplier at >96%, the weighed amount can be used without correction
to calculate the concentration of the solution (5 iiq/u,n store the
amber vials at 4° C or less.
7.7 Primary dilution standard solution. The stock standard solutions
are used to prepare a primary dilution standard solution that
contains multiple analytes. Mixtures of these analytes to be used
as primary dilution standards may be purchased from commercial
suppliers. Do not put every method analyte in a single primary
dilution standard because chromatographic separation will be
extremely difficult, if not impossible. Two or three primary
dilution standards would be more appropriate. The recommended
solvent for these standards is acetone or ethyl acetate. Aliquots
of each of the stock standard solutions are combined to produce the
primary dilution in which the concentration of the analytes is at
least equal to the concentration of the most concentrated
calibration solution, that is, 10 ng//il_. Store the primary dilution
standard solution in an amber vial at 4° C or less, and check
frequently for signs of degradation or evaporation, especially just
before preparing calibration solutions.
7.8 Fortification solution of internal standards and surrogates
Prepare an internal standard solution of acenaphthene-D1fl
phenanthrene-D10, and chrysene-D12, in methanol, ethyl acetate, or
acetone at a concentration of 500 ng/ml of each. This solution is
used in the preparation of the calibration solutions. Dilute a
portion of this solution by 10 to a concentration of 50 /ig/mL and
use this solution to fortify the actual water samples (see Sect
.11.1.3 and Sect. 11.2.3). Similarly, prepare both surrogate
compound solutions (500/yg/mL for calibration, 50//g/mL for
fortification). Surrogate compounds used in developing this method
are l,3-dimethyl-2-nitrobenzene, perylene-D12, and
triphenylphosphate. Other surrogates, for example pyrene-D1n may be
used in this solution as needed (a 100-/iL aliquot of this 50 /ig/mL
solution added to 1 L of water gives a concentration of 5 /zg/L of
each internal standard or surrogate). Store these solutions in an
amber vial at 4° C or less. These two solutions may be combined or
made as a single solution.
7.9 GC/MS performance check solution. Prepare a solution in methylene
chloride of the following compounds at 5 ng//zL of each: DFTPP and
endrin, and 4,4'-DDT. Store this solution in an amber vial at 4° C
or less. DFTPP is less stable in acetone or ethyl acetate than it
is in methylene chloride. '
525.2-1!
-------
7 10 Calibration solutions (CAL1 through CAL6). Prepare a series of six
concentration calibration solutions in ethyl acetate which contain
analytes of interest (except pentachlorophenol, toxaphene, and the
Aroclor compounds) at suggested concentrations of 10, 5, 2, 1, 0.5,
and 0.1 ng//iL, with a constant concentration of 5 ng//iL of each
internal standard and surrogate in each CAL solution. It should be
noted that CAL1 through CAL6 are prepared by combining appropriate
aliquots of a primary dilution standard solution (Sect. 7.7) and the
fortification solution (500 /ig/mL) of internal standards and
surrogates (Sect. 7.8). All calibration solutions should contain at
least 80% ethyl acetate to avoid gas chromatographic problems. IF
ALL METHOD ANALYTES ARE TO BE DETERMINED, TWO OR THREE SETS OF
CALIBRATION SOLUTIONS WILL LIKELY BE REQUIRED. Pentachlorophenol is
included in this solution at a concentration four times the other
analytes. Toxaphene CAL solutions should be prepared as separate
solutions at concentrations of 250, 200, 100, 50, 25, and 10 ng//iL.
Aroclor CAL solutions should be prepared individually at
concentrations of 25, 10, 5, 2.5, 1., 0.5 and 0.2 ng/pl. Store
these solutions in amber vials in a dark cool place. Check these
solutions regularly for signs of degradation, for example, the
appearance of anthraquinone from the oxidation of anthracene.
7.11 Reducing agent. Sodium sulfite, anhydrous. Sodium thiosulfate is
not recommended as it may produce a residue of elemental sulfur that
can interfere with some analytes.
7 12 Fortification solution for recovery standard. Prepare a solution of
terphenyl-Du at a concentration of 500 /ig/mL in methylene chloride
or ethyl acetate. These solutions are also commercially available.
An aliquot of this solution should be added to each extract to check
on the recovery of the internal standards .in the extraction process.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 Sample collection. When sampling from a water tap, open the tap and
allow the system to flush until the water temperature has stabilized
(usually about 2 min). Adjust the flow to about 500 mL/rhin and
collect samples from the flowing stream. Keep samples sealed from
collection time until analysis. When sampling from an open body of
water, fill the sample container with water from a representative
area. Sampling equipment, including automatic samplers, must be
free of plastic tubing, gaskets, and other parts that may leach
interfering analytes into the water sample. Automatic samplers that
composite samples over time should use refrigerated glass sample
containers if possible.
8.2 Sample dechlorination and preservation. All samples should be iced
or refrigerated at 4°C and kept in the dark from the time of
collection until extraction. Residual chlorine should be reduced at
the sampling site by addition of 40-50 mg of sodium sulfite (this
may be added as a solid with stirring or shaking until dissolved) to
each water sample. It is very important that the sample be
525.2-12
-------
dechlorinated prior to adding acid to lower the pH of the sample.
Adding sodium sulfite and HC1 to the sample bottles prior to
shipping to the sampling site is not permitted. Hydrochloric acid
should be used at the sampling site to retard the microbiological
degradation of some analytes in water. The sample pH is adjusted to
<2 with 6 N hydrochloric acid. This is the same pH used in the
extraction, and is required to support the recovery of acidic
compounds like pentachlorophenol. •
8.2.1 If cyanizine is to be determined, a separate sample must be
collected. Cyanazine degrades in the sample when it is
stored under acidic conditions or when sodium sulfite is
present in the stored sample. Samples collected for
cyanazine determination MUST NOT be dechlorinated or
acidified when collected. They should be iced or
refrigerated as described above and analyzed within 14 days.
However, these samples MUST be dechlorinated and acidified
immediately prior to fortification with internal standards
and surrogates, and extraction using the same quantities of
acid and sodium sulfite described above.
8.2.2 Atraton and prometon are not efficiently extracted from water
at pH 2 due to what appears to be their ionization in
solution under acidic conditions. In order to determine
these analytes accurately, a separate sample must be
collected and dechlorinated with sodium sulfite, but no acid
should be added. At neutral pH, these two compounds are
recovered from water with efficiencies greater than 90%. The
data in Tables 3, 4, 5, 6, and 8 are from samples extracted
at pH 2.
8.3 Holding time. Results of the time/storage study of all method
analytes showed that all but six compounds are stable for 14 days in
water samples when the samples are dechlorinated, preserved, and
stored as described in Sect. 8.2. Therefore, samples must be
extracted within 14 days. If the following analytes are to be
determined, the samples cannot be held for 14 days but must be
extracted immediately after collection and preservation: carboxin,
diazinon, disulfoton, disulfoton sulfoxide, fenamiphos, and
terbufos. Sample extracts may be stored at 4° C for up to 30 days
after sample extraction.
8.4 Field blanks.
8.4.1 Processing of a field reagent blank (FRB) is recommended
along with each sample set, which is composed of the samples
collected from the same general sample site at approximately
the same time. At the laboratory, fill a sample container
with reagent water, seal, and ship to the sampling site,along
with the empty sample containers. Return the FRB to the
laboratory with the filled sample bottles.
525.2-13
-------
8.4.2 When sodium sulfite and hydrochloric acid are added to
samples, use the same procedure to add the same amounts to
the FRB. ;
9. QUALITY CONTROL
9.1 Quality control (QC) requirements are the initial demonstration of
laboratory capability followed by regular analyses of laboratory
reagent blanks, laboratory fortified blanks, and laboratory
fortified matrix samples. A MDL should be determined for each
analyte of interest. The laboratory must maintain records to
document the quality of the data generated. Additional quality
control practices are recommended.:
9.2 Initial demonstration of low disk ()r cartridge system background.
Before any samples are analyzed, or any time a new supply of
cartridges or disks is received from a supplier, it must be demon-
strated that a laboratory reagent blank (LRB) is reasonably free of
contamination that would prevent t\\e determination of any analyte of
concern. In this same experiment,: it must be demonstrated that the
particle size and packing of the LSE cartridges or the preparation
of the disks are acceptable. Consistent flow rate with all samples
is an indication of acceptable particle size distribution, packing,
and proper preparation.
9.2.1 A source of potential contamination is the liquid-solid
extraction (LSE) cartridge or disk which could contain
phthalate esters, silicon compounds, and other contaminants
that could prevent the determination of method analytes (5).
Although disks are generally made of an inert matrix, they
may still contain phthalate material. Generally, phthalate
esters can be leached from the cartridges into ethyl acetate
and methylene chloride and produce a variable background in
the water sample. If the background contamination is
sufficient to prevent accurate and precise measurements, the
condition must be corrected before proceeding with the
initial demonstration.
9.2.2 Other sources of background contamination are solvents,
reagents, and glassware. Background contamination must be
reduced to an acceptable level before proceeding with the
next section. In general, background from method analytes
should be below the method detection limits.
9.2.3 One liter of water should pass through a cartridge in about 2
h with a partial vacuum of about 13 cm (5 in.) of mercury.
Using full aspirator or pump vacuum, approximately 5-20 min
will normally be required t;o pass one liter of drinking water
through a disk. The extraction time should not vary
unreasonably among LSE cartridges or disks.
525.2-14
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9.3
9.4
9.3.2
9.3,3
Initial demonstration of laboratory accuracy and precision. Analyze
four to seven replicates of a laboratory fortified blank containing
each analyte of concern at a suggested concentration in the range of
2-5 /jg/L. This concentration should be approximately in the middle
of the calibration range, and will be dependent on the sensitivity
of the instrumentation used.
9.3.1 Prepare each replicate by adding sodium sulfite and HC1
according to Sect. 8.2, then adding an appropriate aliquot of
the primary dilution standard solution, or certified quality
control sample, to reagent water. Analyze each replicate
according to the procedures described in Sect. 11.
Calculate the measured concentration of each analyte in each
replicate, the mean concentration of each analyte in alf
replicates, and mean accuracy (as mean percentage of true
value) for each analyte, and the precision (as relative
standard deviation, RSD) of the measurements for each
analyte. . .
For each analyte and surrogate, the mean accuracy, expressed
as a percentage of the true value, should be 70-130% and the
RSD should be <30%. If these criteria are not met, locate
the source of the problem, and repeat with freshly oreoared
LFBs. •
Analyze seven replicate laboratory fortified blanks which
have been fortified with all analytes of interest at
approximately 0.5 /ig/L. Calculate the MDL of each analyte
using the procedure described in Sect. 13.1.2 (1). It is
recommended that these analyses be performed over a period of
three or four days to produce more realistic method detection
limits.
9.3.5 Develop and maintain a system of control charts to plot the
precision and accuracy of analyte and surrogate measurements
as a function of time. Charting of surrogate recoveries is
an especially valuable activity since these are present in
every sample and the analytical results will form a
significant record of data quality.
Monitor the integrated areas of the quantitation ions of the
internal standards and surrogates in continuing .calibration checks
(see Sect. 10.3). In laboratory fortified blanks or samples, the
integrated areas of internal standards and surrogates will not be
constant because the volume of the extract will vary (and is
difficult to keep constant). But the ratios of the areas should be
reasonably constant in laboratory fortified blanks and samples. The
addition of 10 fj.1 of the recovery standard, terphenyl-D14 (500
/ig/mL), to the extract is recommended to be used to monitor the
recovery of the internal standards in laboratory fortified blanks
and samples. Internal standard recovery should be in excess of 70%.
9.3.4
525.2-15
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9.5
9.6
9.7
9.8
With each batch of samples processed as a group within a 12 h work
shift, analyze a laboratory reagent blank to determine the
background system contamination. Any time a new batch of LSE
cartridges or disks is received, or new supplies of other reagents
are used, repeat the demonstration of low background described in
Sect. 9.2. !
With each batch of samples processed as a group within a work shift,
analyze a single laboratory fortified blank (LFB) containing each
analyte of concern at a concentration as determined in Sect. 9.3.
If more than 20 samples are Included in a batch, analyze a LFB for
every 20 samples. Use the procedures described in Sect. 9.3.3 to
evaluate the accuracy of the measurements. If acceptable accuracy
cannot be achieved, the problem must be located and corrected before
additional samples are analyzed. Add the results to the on-going
control charts to document data quality.
Note: If the LFB for each batch of samples contains the individual
PCB congeners listed in Section 1, then a LFB for each Aroclor is
not required. At least one LFB containing toxaphene should be
extracted for e.ach 24 hr period during which extractions are
performed. Toxaphene should be fortified in a separate LFB from
other method analytes.
If individual PCB congeners are not part of the LFB, then it is
suggested that one multi-component analyte (toxaphene, chlordane or
an Aroclor) LFB be analyzed with each sample set. By selecting a
different multi-component analyte for this LFB each work shift, LFB
data can be obtained for all of these analytes over the course of
several days.
Determine that the sample matrix does not contain materials that
adversely affect method performance. This is accomplished by
analyzing replicates of laboratory fortified matrix samples and
ascertaining that the precision, accuracy, and method detection
limits of analytes are in the same range as obtained with laboratory
fortified blanks. If a variety of different sample matrices are
analyzed regularly, for example, drinking water from groundwater and
surface water sources, matrix independence should be established for
each. Over time, LFM data should be documented for all routine
sample sources for the laboratory. A laboratory fortified sample
matrix should be analyzed for every 20 samples processed in the same
batch. If the recovery data for a LFM does not meet the criteria in
Sect. 9.3.3., and LFBs show the laboratory to be in control , then
the samples from that matrix (sample location) are documented as
suspect due to matrix effects.
With each set of samples, a field reagent blank (FRB) should be
analyzed. The results of this analysis will help define
contamination resulting from field sampling and transportation
activities.
525.2-16
-------
9.9 At least quarterly, analyze a quality-control sample from an
external source. If measured analyte concentrations are not of
acceptable accuracy (Sect. 9.3.3), check the entire analytical
procedure to locate and correct the problem source.
9.10 Numerous other quality control measures are incorporated into other
parts of this procedure, and serve to alert the'analyst to
potential problems.
10. CALIBRATION AND STANDARDIZATION
10.1 Demonstration and documentation of acceptable initial calibration is
required before any samples are analyzed and is required
intermittently throughout sample analysis as dictated by results of
continuing calibration checks. After initial calibration is
successful, a continuing calibration check is required each day or
at the beginning of each period in which analyses are performed not
to exceed 12 h. Additional periodic calibration checks are good
laboratory practice. It is recommended that an additional
calibration check be performed at the end of each period of
continuous instrument operation, so that all field sample analyses
are bracketed by a calibration check standard.
10.2 Initial calibration
10.2.1 Calibrate the mass and abundance scales of the MS with
calibration compounds and procedures prescribed by the
manufacturer with any modifications necessary to meet the
requirements in Sect. 10.2.2.
10.2.2 Inject into the GCf S system a 1 /jl aliquot of the 5 nq/uL
solution of DFTPP, endrin and 4,4'-DDT. If desired, the
endrin and DDT degradation checks may be performed
simultaneously with the DFTPP check or in a separate
injection. Acquire a mass spectrum that includes data for
m/z 45-450. Use GC conditions that produce a narrow (at
least five scans per peak) symmetrical peak for each compound
(Sect. 10.2.3.1 and Sect. 10.2.3.2). If the DFTPP mass
spectrum does not meet all criteria in Table: 1, the MS must
be retuned and adjusted to meet all criteria before
proceeding with calibration. A single spectrum or an average
spectrum across the GC peak may be used to evaluate the
performance of the system. Locate any degradation products
of endrin (endrin ketone [EK] and endrin aldehyde FEA1) and
4,4'-DDT (4,4'-DDE and 4,4'-DDD).at their appropriate
retention times and quantisation ions (Table 2). Endrin
ketone can be located at =1.1 to 1.2 times the endrin
retention time with prominent m/z 67 and 317 ions in the mass
spectrum. If degradation of either endrin or DDT exceeds
20%, maintenance is required on the GC injection port and
possibly other areas of the system before proceeding with the
525.2-17
-------
calibration. Calculate percent breakdown using peak areas
based on total ion current (TIC) as follows:
% 4,4'-DDT breakdown= ;
I TIC area of DDT degradation peaks (DDE+DDD)
I TIC area of total DDT peaks (DDT+DDE+DDD)
X 100
% endrin breakdown=
I TIC area of endrin degradation peaks (EA+EK)
I TIC area of total endrin peaks (endrin+EA+EK)
X 100
10.2.3 Inject a 1-juL aliquot of a medium concentration calibration
solution, for example 0.5-2 M9/L, and acquire and store data
from m/z 45-450 with a total cycle time (including scan
overhead time) of 1.0 sec or less. Cycle time should be
adjusted to measure at least :five or more spectra during the
elution of each GC peak. Calibration standards for toxaphene
and Aroclors must be injected individually.
10.2.3.1 The following are suggested multi-ramp temperature
program GC conditions. Adjust the helium carrier
gas flow rate to about 33 cm/sec. Inject at 45°C
and hold in splitless mode for 1 min. Heat rapidly
to 130°C. At 3 min start the temperature program:
130-180°C at 12°/min; 180-240°C at 7°/min; 240-320°C
at 12°/min. Start data acquisition at 4 min.
10.2.3.2 Single ramp linear temperature program suggested GC
conditions. Adjust the helium carrier gas flow rate
to about 33 cm/sec. Inject at 40°C and hold in
splitless mode for 1 min. Heat rapidly to 160°C.
At 3 min start the temperature program: 160-320°C at
6°/min; hold at 320° for 2 min. Start data
acquisition at 3 min.
10.2.4 Performance criteria for the calibration standards. Examine
the stored GC/MS data with the data system software.
10.2.4.1 GC performance. Anthracene and phenanthrene should
be separated by baseline. Benz[a]anthracene and
chrysene should be separated by a valley whose
height is less than 25% of the average peak height
of these two compounds. If the valley between
benz[a]anthracene and chrysene exceeds 25%, the GC
column requires maintenance. See Sect. 10.3.6.
I
10.2.4.2 MS sensitivity. The GC/MS/DS peak identification
software should be able to recognize a GC peak in
525.2-18
-------
the appropriate retention time window for each of
the compounds in the calibration solution, and make
correct identifications. If fewer than 99% of the
compounds are recognized, system maintenance is
required. See Sect. 10.3.6.
10.2.5 If all performance criteria are met, inject a l-/iL aliquot of
each of the other CAL solutions using the same GC/MS
conditions. Calibration standards of toxaphene and Aroclors
must be injected individually.
10.2.5.1 Some GC/MS systems may not be sensitive enough to
detect some of the analytes in the two lowest
concentration CAL solutions. In this case, the
analyst should prepare additional CAL solutions at
slightly higher concentrations to obtain at least 5
calibration points that bracket the expected analyte
concentration range.
10.2.6 Calculate a response factor (RF) for each analyte of interest
and surrogate for each CAL solution using the internal
standard whose retention time is nearest the retention time
of the analyte or surrogate. Table 2 contains suggested
internal standards for each analyte and surrogate, and
quantitation ions for all compounds. This calculation is
supported in acceptable GC/MS data system software (Sect.
6.10.4), and many other software programs. The RF is a
unitless number, but units used to express quantities of
analyte and internal standard must be equivalent.
Note: To calibrate for multi-component analytes (toxaphene
and Aroclors), one of the following methods should be used.
Option 1- Calculate an average response factor or linear
regression equation for each multi-component analyte from the
combined area of all its component peaks identified in the
calibration standard chromatogram, using 2-3 of the suggested
quantitation ions in Table 2.
Option 2- Calculate an average response factor or linear
regression equation for each multi-component analyte using
the combined areas of 3-6 of the most intense and
reproducible peaks in each of the calibration standard
chromatograms. Use an appropriate quantitation ion for each
peak.
RF =
•CA,.j(Qx)
525.2-19
-------
where:
A, =
A _
Mis ~
Ql
integrated abundance of the quantitation ion
of the analyte;.
integrated abundance of the quantitation ion
internal standard.
quantity of analyte injected in ng or
concentration units.
quantity of internal standard injected in ng
or concentration units.
10.2.6.1 For each analyte and surrogate, calculate the mean
RF from the analyses of the six CAL solutions.
Calculate the standard deviation (SD) and the
relative standard deviation (RSD) from each mean:
RSD = 100 (SD/M). If the RSD of any analyte or
surrogate mean RF exceeds 30%, either analyze
additional aliquots of appropriate CAL solutions to
' obtain an acceptable RSD of RFs over the entire
concentration range, or take action to improve GC/MS
performance. See Sect. 10.3.6.
10.2.7 As an alternative to calculating mean response factors, use
the GC/MS data system software or other available software to
generate a linear regression calibration by plotting Ax /Ais
vs. Qx.
10.3 Continuing calibration check. Verify the MS tune and initial
calibration at the beginning of each 12 h work shift during which
analyses are performed using the following procedure.
10.3.1 Inject a 1-0L aliquot of the |5 ng//uL solution of DFTPP,
endrin, and 4,4'-DDT. Acquire a mass spectrum for DFTPP that
includes data for m/z 45-450. Ensure that all criteria in
Sect. 10.2.2 are met.
10.3.2 Inject a l-/iL aliquot of a calibration solution
with the same conditions used during the initial
It is recommended that the concentration of cali
solution be varied, so that the calibration can
at more than one point. Note: If the continuing
check standard contains the PCB congeners listed
1, calibration verification js not required for
Calibration verification of toxaphene should be
least once each 24 hr period.
and analyze
calibration.
bration
be verified
calibration
in Section
each Aroclor.
performed at
10.3.3 Demonstrate acceptable performance for the criteria shown in
Sect. 10.2.4.
10.3.4 Determine that the absolute areas of the quantitation ions of
the internal standards and surrogate(s) have not changed by
more than 30% from the areas measured in the most recent
continuing calibration check; or by more than 50% from the
525.2-20
-------
areas measured during initial calibration. If these areas
have decreased by more than these amounts, adjustments must
be made to restore system sensitivity. These adjustments may
require cleaning of the MS ion source, or other maintenance
as indicated in Sect. 10.3.6,,and recalibration. Control
charts are useful aids in documenting system sensitivity
changes.
10.3.5 Calculate the RF for each analyte and surrogate from the data
measured in the continuing calibration check. The RF for
each analyte and surrogate must be within 30% of the mean
value measured in the initial calibration. Alternatively, if
a linear regression is used, the calculated amount for each
analyte must be ± 30% of the true value. If these conditions
do not exist, remedial action should be taken which may
require recalibration. Any field sample extracts that have
been analyzed since the last acceptable calibration
verification should be reanalyzed after adequate calibration
has been restored.
10.3.5.1 Because of the large number of compounds on the
analyte list, it is possible for a few analytes.of
interest to.be outside the continuing calibration
criteria. If analytes that missed the calibration
check are detected in samples, they may be
quantified using a single point calibration. The
single point standards should be prepared at
concentrations that produce responses close (±20%)
to those of the unknowns. If the same analyte
misses the continuing calibration check on three
consecutive work shifts, remedial action MUST be
taken. If more than 10% of the analytes of interest
miss the continuing calibration check on a single
day, remedial action MUST.be taken.
10.3.6 Some possible remedial actions. Major maintenance such as
cleaning an ion source, cleaning quadrupole rods, replacing
filament assemblies, etc. require returning to the initial
calibration step.
10.3.6.1 Check and adjust GC and/or MS operating conditions;
check the MS resolution, and calibrate the mass
scale.
10.3.6.2 Clean or replace the splitless injection liner;
silanize a new injection liner.
10.3.6.3 Flush the GC column with solvent according to
manufacturer's instructions.
10.3.6.4 Break off a short portion (about 1 meter) of the
column from the end near the injector; or replace GC
525.2-21
-------
column. This action will cause a change in
retention times.
10.3.6.5 Prepare fresh CAL ^solutions, and repeat the initial
calibration step.
10.3.6.6 Clean the MS ion source and rods (if a quadrupole).
j:
10.3.6.7 Replace any components that allow analytes to come
into contact with hot metal surfaces.
10.3.6.8 Replace the MS electron multiplier, or any other
faulty components.
11. PROCEDURE
11.1 CARTRIDGE EXTRACTION
11.1.1 This procedure may be carried out in the manual mode or in
the automated mode (Sect. 6.12) using a robotic or automatic
sample preparation device. If an automatic system is used to
prepare samples, follow the manufacturer's operating
instructions, but follow this procedure. If the manual mode
is used, a suggested setup of the extraction apparatus is
shown in Figure 1A. The reservoir is not required, but
recommended for convenient operation. Water drains from the
reservoir through the LSE cartridge and into a syringe needle
which is inserted through a rubber stopper into the suction
flask. A slight vacuum of approximately 13 cm (5 in.) of
mercury is used during all operations with the apparatus.
About 2 h should be required to draw a liter of water through
the cartridge.
11.1.2 Elute each cartridge with a 5 mL aliquot of ethyl acetate
followed by a 5 mL aliquot of methylene chloride. Let the
cartridge drain dry after each flush. Then elute the
cartridge with a 10 mL aliquot of methanol, but DO NOT allow
the methanol to elute below the top of the cartridge packing.
From this point, do not allow the cartridge to go dry. Add
10 mL of reagent water to the cartridge, but before the
reagent water level drops below the top edge of the packing,
begin adding sample to the solvent reservoir.
11.1.3 Pour the water sample into the 2-L separatory funnel with the
stopcock closed, add 5 mL methanol, and mix well. If a
vacuum manifold is used instead of the separatory funnel, the
sample may be transferred directly to the cartridge after the
methanol is added to the sample. (Residual chlorine should
not be present as a reducing agent should have been added at
the time of sampling. Also the pH of the sample should be
about 2. If residual chlorine is present and/or the pH is
>2, the sample may be invalid.) Add a 100-/JL aliquot of the
525.2-22
-------
fortification solution (50 /Kj/mL) for internal standards and
surrogates, and mix immediately until homogeneous. The
resulting concentration of these compounds in the water
should be 5
11.1.4 Periodically transfer a portion of the sample into the
solvent reservoir. The water sample will drain into the
cartridge, and from the exit into the suction flask.
Maintain the packing material in the cartridge immersed in
water at all times. After all of the sample has passed
through the LSE cartridge, draw air or nitrogen through the
cartridge for 10 min.
11.1.5 Transfer the 125-mL solvent reservoir and LSE cartridge (from
Figure 1A) to the elution apparatus if used (Figure IB). The
same 125-mL solvent reservoir is used for both apparatus.
Rinse the inside of the 2-L separatory funnel and the sample
jar with 5 mL of ethyl acetate, and elute the cartridge with
this rinse into the collection tube. Wash the inside of the
separatory funnel and the sample jar with 5 mL methylene
chloride and elute the cartridge, collecting the rinse in the
same collection tube. Small amounts of residual water from
the sample container and the LSE cartridge may form an
immiscible layer with the eluate. Pass the eluate through
the drying column (Sect. 6.7) which is packed with
approximately 5 to 7 grams of anhydrous sodium sulfate and
collect in a second vial. Wash the sodium sulfate with at
least 2 mL methylene chloride and collect in the same vial.
Concentrate the extract in a warm water bath under a gentle
stream of nitrogen. Do not concentrate the extract to less
than 0.5 mL, as this will result in losses of analytes. Make
any volume adjustments with ethyl acetate. It is recommended
that an aliquot of the recovery standard be added to the
concentrated extract to check the recovery of the internal
standards (see Sect. 7.12).
11.2 DISK EXTRACTION
11.2.1 This procedure was developed using the standard 47 mm
diameter disks. Larger disks (90 mm diameter) may be used if
sample compositing is being done or special matrix problems
are encountered. If larger disks are used, the washing
solvent volume is 15 mL, the conditioning solvent volume is
15 mL, and the elution solvent volume is two 15 mL aliquots.
11.2.1.1 Extractions using the disks may be carried out
either in the manual or automatic mode (Sect. 6.12)
using an automatic sample preparation device. If an
automatic system is used to prepare samples, follow
the manufacturer's operating instructions, but
follow this procedure. Insert the disk into the
filter apparatus (Figure 2) or sample preparation
525.2-23
-------
unit. Wash the disk with 5 ml of a 1:1 mixture of
ethyl acetate (EtAc) and methylene chloride (MeC12)
by adding the solvent to the disk, drawing about
half through the disk, allowing it to soak the disk
for about a minute, then drawing the remaining
solvent through the disk. (NOTE: Soaking the disk
may not be desirable when disks other than Teflon
are used. Instead, apply a constant, low vacuum in
this Section and Sect. 11.2.1.2 to ensure adequate
contact time between solvent and disk.)
11.2.1.2 Pre-wet the disk with 5 ml methanol (MeOH) by adding
the MeOH to the disk and allowing it to soak for
about a minute, then drawing most of the remaining
MeOH through. A layer of MeOH must be left on the
surface of the disk, which should not be allowed to
go dry from this point until the end of the sample
extraction. THIS IS A CRITICAL STEP FOR A UNIFORM
FLOW AND GOOD RECOVERY.
11.2.1.3 Rinse the disk with 5 mL reagent water by adding the
water to the disk and; drawing most through, again
leaving a layer on the surface of the disk.
11.2.2 Add 5 mL MeOH per liter of water to the sample. Mix well.
(Residual chlorine should not be present as a reducing agent
should have been added at the time of sampling. Also the pH
of the sample should be about 2. If residual chlorine is
present and/or the pH is >2, the sample may be invalid.)
11.2.3 Add 100 ill of the internal standard and surrogate compound
fortification solution (50 /ig/mL) to the sample and shake or
mix until the sample is homogeneous. The resulting
concentration of these compounds in the water should be 5
11.2.4 Add the water sample to the reservoir and apply full vacuum
to begin the extraction. Particulate-free water may pass
through the disk in as little as 5 min without reducing
analyte recoveries. Extract the entire sample, draining as
much water from the sample container as possible. Dry the
disk by maintaining vacuum for about 10 min.
11.2.5 Remove the filtration top, but do not disassemble the
reservoir and fritted base. If a suction flask is being
used, empty the water from the flask, and insert a suitable
collection tube to contain the eluant. The only constraint
on the sample tube is that it fit around the drip tip' of the
fritted base. Reassemble the apparatus.
11.2.6 Add 5 mL of ethyl acetate to the sample bottle, and rinse the
inside walls thoroughly. Allow the solvent to settle to the
bottom of the bottle, then transfer it to the disk. A
disposable pipet or syringe may be used to do this, rinsing
the sides of the glass filtration reservoir in the process.
525.2-24
-------
Draw about half of the solvent through the disk, release the
vacuum, and allow the disk to soak for a minute. Draw the
remaining solvent through the disk. (NOTE: Soaking the disk
may not be desirable if disks other than Teflon are used.
Instead, apply a constant, low vacuum in this Section and
Sect. 11.2.7 to ensure adequate contact time between solvent
and disk.)
11.2.7 Repeat the above step (Sect. 11.2.6) .with methylene chloride.
11.2.8 Using a syringe or disposable pipet, rinse the filtration
reservoir with two 3 ml portions of 1:1 EtAc:MeC12. Draw the
solvent through the disk and into the collector tube. Pour
the combined eluates (Sect. 11.2.6, Sect. 11.2.7, and Sect.
11.2.8) through the drying tube (Sect. 6.7) containing about
5 to 7 grams of anhydrous sodium sulfate. Rinse the drying
tube and sodium sulfate with two 3 ml portions of 1:1
EtAc:MeC12 mixture. Collect all the extract and washings in
a concentrator tube.
11.2.9 While gently heating the extract in a water bath or a heating
block, concentrate to between 0.5 and 1 mL under a gentle
stream of nitrogen. Do not concentrate the extract to less
than 0.5 mL, since this will result in losses.of analytes.
Make any volume adjustments with ethyl acetate. It is '
recommended that an aliquot of the recovery standard be added
to the concentrated extract to check the recovery of the
internal standards (see Sect. 7.12).
11.3 Analyze a 1 /iL aliquot with the GC/MS system under the same
conditions used for the initial and continuing calibrations (Sect.
10.2.3).
11.4 At the conclusion of data acquisition, use the same software that
was used in the calibration procedure to tentatively identify peaks
.in predetermined retention time windows of interest. Use the data
system software to examine the ion abundances of components of the
chromatogram.
11.5 Identification of analytes. Identify a.sample component by
comparison of its mass spectrum (after background subtraction) to a
reference spectrum in the user-created data base. The GC retention
time of the sample component should be within 5 sec of the retention
time observed for that same compound in the most recently analyzed
continuing calibration check standard.
11.5.1 In general, all ions that are present above 10% relative
abundance in the mass spectrum of the standard should be
present in the mass spectrum of the sample component and
should agree within absolute 20%. For example, if an ion has
a relative abundance of 30% in the standard spectrum., its
abundance in the sample spectrum should be in the range of 10
525.2-25
-------
to 50%. Some ions, particularly the molecular ion, are of
special importance, and should be evaluated even if they are
below 10% relative abundance.
11.5.2 Identification is hampered when sample components are not
resolved chromatographically and produce mass spectra
containing ions contributed by more than one analyte. When
GC peaks obviously represent more than one sample component
(i.e., broadened peak with shoulder(s) or valley between two
or more maxima), appropriate analyte spectra and background
spectra can be selected by examining plots of characteristic
ions for tentatively identified components. When analytes
coelute (i.e., only one GC peak is apparent), the
identification criteria can be met but each analyte spectrum
will contain extraneous ions contributed by the coeluting
compound.
11.5.3 Structural isomers that produce very similar mass spectra can
be explicitly identified only if they have sufficiently
different GC retention times. See Sect. 10.2.4.1.
Acceptable resolution is achieved if the height of the valley
between two isomer peaks is less than 25% of the average
height of the two peak heights. Otherwise, structural
isomers are identified as iisomeric pairs. Benzo[b] and
benzo[k]fluoranthene may be measured as an isomeric pair.
MGK 264 is made up of two structural isomers. These are
listed separately in the data tables.
i
11.5.4 Each multi-component analyse can be identified by the
presence of its individual components in a characteristic
pattern based on the relative amounts of each component
present. Chromatograms of standard materials of multi-
component analytes should be carefully evaluated, so that
these patterns can be recognized by the analyst.
1
12. DATA ANALYSIS AND CALCULATIONS ;
12.1 Complete chromatographic resolution is not necessary for accurate
and precise measurements of analyte concentrations if unique ions
with adequate intensities are avail able for quantitation. In
validating this method, concentrations were calculated by measuring
the characteristic ions listed in Table 2. If the response of any
analyte exceeds the calibration riage established in Section 10,
dilute the extract and reanalyze.
12.1.1 Calculate analyte and surrogate concentrations, using the
multipoint calibration established in Sect. 10. Do not use
daily calibration verification data to quantitate analytes in
samples. ;
(Ais) RF V
525.2-26
-------
where:
A.
As =
Qis -
v =
RF =
concentration of analyte or surrogate in (j.g/1 in
the water sample.
integrated abundance of the quantitation ion of
the analyte in the sample.
integrated abundance of the quantitation ion of
the internal standard in the sample.
total quantity (in micrograms) of internal
standard added to the water sample.
original water sample volume in liters.
mean, response factor of analyte from the initial
calibration. RF is a unitless value.
12.1.2 Alternatively, use the GC/MS system software or other
available proven software to compute the concentrations of
the analytes and surrogates from the linear regression
established in Sect. 10. Do not use daily calibration
verification data to quantitate analytes in samples.
12.1.3 Calculations should utilize all available digits of
precision, but final reported concentrations should be
rounded to an appropriate number of significant figures (one
digit of uncertainty). Experience indicates that three
significant figures may be used for concentrations above 99
two significant figures for concentrations between 1-99
and one significant figure for lower concentrations.
12.2 To quantitate multi-component analytes (toxaphene and Aroclors), one
of the following methods should be used.
Option 1 - Calculate an average RF or linear regression equation for
each multi -component analyte from the combined area of all its
component peaks identified in the calibration standard chromatogram,
using 2-3 of the suggested quantitation ions in Table 2.
Option 2 - Calculate an average response factor or linear regression
equation for each multi-component analyte using the combined areas
of 3-6 of the most intense and reproducible peaks in each of the
calibration standard chromatograms.
When quantifying multi-component analytes in samples, the analyst
should use caution to include only those peaks from the sample that
are attributable to the multi-component analyte. Option 1 should
not be used if there are significant interference peaks within the
Aroclor or toxaphene pattern. Option 2 was used to generate the
data in Table 6.
13. METHOD PERFORMANCE
13.1 Single laboratory accuracy and precision data (Tables 3-6) for each
listed analyte (except multi-component analytes) were obtained at a
525.2-27
-------
concentration of 0.5 /*g/L and/or 5 fJy/L in reagent water utilizing
both the disk and the cartridge technology and two different GC/MS
systems, an ion trap and a quadrupole mass spectrometer. Table 8
lists accuracy and precision data from replicate determinations of
method analytes in tap water using liquid-solid cartridge
extractions and the ion trap mass spectrometer. Any type of GC/MS
system may be used to perform this method if it meets the
requirement in Sect. 6.10 and the quality control criteria in Sect.
9. The multi-component analytes (i.e. toxaphene and Aroclors) are
presented in Tables 5 and 6. The average recoveries in the tables
represent six to eight replicate analyses done over a minimum of a 2
day period.
13.1.2 With these data, the method detection limits (MDL) in the
tables were calculated using the formula:
MDL = S t^..,
where:
t,,, 1 1 „!„.,, _ n oo>
\T\" I • \ "aipna — u«yy j
0-99)
= Student's t value for the 99% confidence
_ , , . . r- r- \
level with n-1 degrees of freedom
n = number of replicates
S - standard deviation of replicate analyses.
13.2 Problem compounds
13.2.1 Some polycyclic aromatic hydrocarbons (PAH), including the
labeled PAHs used in this method as internal standards, are
rapidly oxidized and/or chlorinated in water containing
residual chlorine. Therefore, residual chlorine must be
reduced at the time of sampling. .These same types of
compounds, especially anthracene, benz[a]anthracene, and
benzo[a]pyrene, are susceptible to photodegradation.
Therefore, care should be taken to avoid exposing standards,
samples, and extracts to direct light. Low recoveries of
some PAH compounds have been observed when the cartridge or
disk was air dried longer than 10 min (Sect. 11.1.4 and Sect.
11.2.4). Drying times longer than 10 min should be avoided,
or nitrogen may be used to dry the cartridge or disk to
minimize the possible oxidation of these analytes during the
drying step.
13.2.2 Merphos is partially converted to DEF in aqueous matrices,
and also when introduced into a hot gas chromatographic
injection system. The efficiency of this conversion appears
to be unpredictable and not reproducible. Therefore, merphos
cannot be quantified and can only be identified by the
presence of DEF in the sample.
13.2.3 Several of the nitrogen and/or phosphorus containing
pesticides listed as method analytes are difficult to
525.2-28
-------
chromatograph and appear as broad, asymmetrical peaks. These
analytes, whose peak shapes are typically poor, are listed in
Table 7. The method performance for these analytes is
strongly dependent on chromatographic efficiency and
performance. Poor peak shapes will affect the linearity of
the calibration curves and result in poor accuracy at low
concentrations. Also listed in Table 7 are data generated at
a mid-concentration level for these analytes. In most cases,
the data at this concentration meet the quality control
criteria requirements of the method.
13.2.4 Phthalate esters and other background components appear in
variable quantities in laboratory and field reagent blanks,
and generally cannot be accurately measured at levels below
about 2 /tg/L. Subtraction of the concentration in the blank
from the concentration in the sample at or below the 2 jag/L
level is not recommended because the concentration of the
background in the blank is highly variable.
13.2.5 Atraton and prometon are not efficiently extracted from the
water at pH 2 due to what appears to be their ionization
occurring in solution under acidic conditions. In order to
determine these analytes accurately, a separate sample must
be collected and dechlorinated with sodium sulfite, but no
HC1 should be added at.the time of collection. At neutral
pH, these two compounds are recovered from water with
efficiencies greater than 90%. The data in Tables 3, 4, 5,
6, and 8 are from samples extracted at pH 2.
13.2.6 Carboxin, disulfoton, and disulfoton sulfoxide were found to
be unstable in water and began to degrade almost immediately.
These analytes may be identified by this method but not
accurately measured.
13.2.7 Low recoveries of metribuzin were observed in samples
fortified with relatively high concentrations of additional
method analytes. In samples fortified with approximately 80
analytes at 5 /ig/L each, metribuzin was recovered at about
50% efficiency. This suggests that metribuzin may break
through the C-18 phase in highly contaminated samples
resulting in low recoveries.
"13.2.8 If cyanazine is to be determined, a separate sample must be
collected. Cyanazine degrades in the sample when it is
stored under acidic conditions or when sodium sulfite is
present in the stored sample. Samples collected for
cyanazine determination MUST NOT be dechlorinated or
acidified when collected. They should be iced or
refrigerated and analyzed within 14 days. However, these
samples MUST be dechlorinated and acidified immediately prior
to fortification with internal standards and surrogates, and
extraction using the same quantities of acid and sodium
sulfite described in Sect. 8.
525.2-29
-------
14. POLLUTION PREVENTION
14.1 This method utilizes liquid-solid extraction (LSE) technology to
remove the analytes from water. It requires the use of very small
volumes of organic solvent and very small quantities of pure
analytes, thereby eliminating the potential hazards to both the
analyst and the environment involved with the use of large volumes
of organic solvents in conventional liquid-liquid extractions.
I
14.2 For information about pollution prevention that may be applicable to
laboratory operations, consult "Less Is Better: Laboratory Chemical
Management for Waste Reduction" available from the American Chemical
Society's Department of Government Relations and Science Policy,
1155 16th Street N.W., Washington, D.C., 20036.
15. WASTE MANAGEMENT
15.1 It is the laboratory's responsibility to comply with all federal,
state, and local regulations governing waste management, particu-
larly the hazardous waste identification rules and land disposal
restrictions. The laboratory using this method has the respons-
ibility to protect the air, water, and land by minimizing and
controlling all releases from fume hoods and bench operations.
Compliance is also required with any sewage discharge permits and
regulations. For further information on waste management, see "The
Waste Management Manual for Laboratory Personnel," also avail-able
from the American Chemical Society at the address in Sect. 14.2.
16. REFERENCES
1. Glaser, J. A., D. L. Foerst, G. D. McKee, S. A. Quave, and W. L. Budde,
"Trace Analyses for Wastewaters," Environ. Sci. Technol. 1981 15.,
1426-1435. or 40 CFR, Part 136, Appendix B.
2. "Carcinogens - Working With Carcinogens," Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77-206, Aug. 1977.
3. "OSHA Safety and Health Standards, General Industry," (29CFR1910),
Occupational Safety and Health Administration, OSHA 2206, (Revised,
January 1976).
4. "Safety in Academic Chemistry Laboratories," American Chemical Society
Publication, Committee on Chemical Safety, 3rd Edition, 1979.
5. Junk, G. A., M. J. Avery, J. J. Richard, "Interferences in Solid-Phase
Extraction Using C-18 Bonded Porous Silica Cartridges," Anal. Chem. 1988,
60, 1347.
525.2-30
-------
17. TABLES. DIAGRAMS. FLOWCHARTS. AND VALIDATION DAtA
TABLE 1. ION ABUNDANCE CRITERIA FOR BIS(PERFLUOROPHENYL)PHENYL
• PHOSPHINE (DECAFLUOROTRIPHENYLPHOSPHINE, DFTPP)
Mass Relative Abundance
(M/z) Criteria
Purpose of Checkpoint1
51 10-80% of the base peak
68 <2% of mass 69
70 <2% of mass 69
127 10-80% of the base peak
197 <2% of mass 198
198 base peak or >50% of 44'2
199 5-9% of mass 198
275 10-60% of the base peak
365 >1% of the base peak
441 Present and < mass 443
442 base peak or >50% of 198
443 15-24% of mass 442
.low mass sensitivity
low mass resolution
low mass resolution '
low-mid mass sensitivity
mid-mass resolution
mid-mass resolution and sensitivity
mid-mass resolution and.isotope ratio
mid-high mass sensitivity
baseline threshold
high mass resolution
high mass resolution: and sensitivity
high mass resolution and isotope ratio
All ions are used primarily to check the mass
spectrometer and data system, and this is the
performance test. The three resolution checks
abundance isotope ratios, constitute the next'
performance test. The correct setting of the
by the presence of low intensity ions, is the
performance test. Finally, the ion abundance
some standardization to fragmentation patterns
measuring accuracy of the mass
most important part of the
, which include natural
most important part of the
baseline threshold, as indicated
next most important part of the
ranges are designed to encourage
525.2-31
-------
TABLE 2.
RETENTION TIME DATA, QUANTITATION IONS, AND INTERNAL STANDARD REFERENCES FOR METHOD ANALYTES
"
Compound
Retention
Time (min:sec)
i A" B"
Quant i tat ion
Ion
IS
Reference
#
'
Internal Standards
acenaphthene-dIO (#1)
chrysene-d12 (#2)
phenanthrene-d10 (#3)
7:47
21 :33
11:37
7:01
18:09
10:13
164
240
188
.
Surrogates
1 ,3-dimethyl-2-nitrobenzene
perylene-d12
triphenylphosphate
5:16
26:60
20:25
4:33
21:31
17:25
134
264
326/325
1
3
3
' . !
Target Analytes
acenaphthylene
alachlor
aldrin
atnetryn
anthracene
Aroclor 1016
ArocLor 1221
Aroclor 1232
Aroclor 1242
Aroclor 1248
Aroclor 1254
Aroclor 1260
atraton
atrazine
benz [a] anthracene
benzo [blfluoranthene
benzo [k] fluoranthene
benzo [g,h,i]perylene
benzo [a] pyrene
bromaci I
butachlor
butylate
butylbenzylphthalate
carboxin
7:30
12:59
14:24
13:11
f11:50
,-,
10:31
10:49
21 :31
25:33
25:45
31:16
25:24
13:46
16:25
I 6:60
19:39
17:37
6:46
11:24
12:31
11:35
10:24
7:30-14:00
6:38-11:25
6:38-13:54
6:38-15:00
8:47-15:00
11:00-18:00
13:10-21:00
9:25
9:38
18:08
20:44
20:48
24:18
21:25
12:03
14:16
6:23
16:53
15:13
152
160
66
227/170
178
152/256/292
152/222/256
152/256/292
152/256/292
152/256/292
220/326/360
326/360/394
196/169
200/215
228
252
252
276
252
205
176/160
57/146
149
143
1
2
2
2
2
2
2
2
2
2
2
2
1
1/2
3
3
3
3
3
2
2
1
2/3
2
525.2-32
-------
TABLE 2. RETENTION TIME DATA, QUANTITATION IONS, AND INTERNAL STANDARD REFERENCES FOR METHOD ANALYTES
(CONTINUED)
• • • • -• II
Compound
Retention
..... Time (min:sec)
Aa Bb
Quant i tat ion
Ion
chlordane, (alpha-chlordane)
chlordane, (gamma-chlordane)
chlordane, (trans-nonachlor)
chlorneb
chlorobenzilate
2-chlorobiphenyl ,
chlorprophara
chlorpyrifos
chlorothalonil
chrysene
cyanazine
cycloate
DCPA
4,4'-DDD
4,4'-DDE
4,4'-DDT
DEF
diazinon
dibenz [ [a, h] anthracene
di-n-butylphthalate
2,3-dichlorobiphenyl
dichlorvos
dieldrin
di(2-ethylhexyl)adfpate
di(2-ethylhexyl)phthalate
diethylphthalate
dimethylphthalate
2,4-dinitrotoluene . . ,
2,6-dimtrotoluene
diphenamid
disulfoton
disulfoton sulfone
disulfoton sulf oxide
16:43
16:19
16:47
7:47
18:22
7:53
9:33
14:10
11:38
21:39
14:14
9:23
14:20
18:40
17:20
19:52
17:24
11:19
30:32
13:49
10:20
5:31
17:35
20:11
22:11
8:68
7:13
8:08
7:19
14:52
11:43
16:28
6:09
14:28
14:05
14:30
7:05
15:52
7:08
8:36
12:23
10:15
18:13
12:28
8:26
12:30
16:05
14:59
17:00
15:05
10:05
23:47
12:07
9-12
4:52
15:09
17:19
18:39
7:53
6:34
7-22
6:40
12:58
10:22
14:17
5:31
375/373
373
409
191
139
188
127
197/97
266
228
225/68
83/154
301
235/165
246
235/165
57 /169
137/179
278
149
109
79
149
149
163
165
165
213/153
IS
Reference
#
2/3
2/3
1
2
1
1
2
1
2
3
1
1
1
1
1
1
1
525.2-33
-------
TABLE 2. RETENTION TIME DATA, QUANTITATION IONS, AND INTERNAL STANDARD REFERENCES FOR METHOD ANALYTES
(CONTINUED) ;
Compound
Retention
Time (minisec)
Aa B"
endosulfan I
endosulfan II
endosulfan sulfate
endrin
endrin aldehyde
EPTC
ethoprop
etridiazole
fenamiphos
fenarimol
fluorene
fluridone
HCH, alpha
HCH, beta
HCH, delta
HCH, gamma (Lindane)
heptachlor epoxide
2,2' ,3,3' ,4,4' ,6-heptachlorobiphenyl
hexach lorobenzene
2,2',4,4',5,6'-hexachlorobiphenyl
hexazinone
indenoC1r2,3-cd]pyrene
isophorone
merphos
methoxychlor
methyl paraoxon
tnetolachlor
metribuzin
mevinphos
HCK 264 - isomer a
MGK 264 - isomer b
16:44
18:35
19:47
18:15
19:02
6:23
9:19
7:14
16:48
23:26
8:59
26:51
10:19
10:57
11:57
11:13
13:19
15:34
21:23
10:27
17:32
5:16
20:00
30:26
4:54
15:38
21 :36
11:57
14:07
12:46
5:54
15:18
14:55
14:26
15:59
.' 16:54
15:42
16:20
5:46
8:23
6:37
14:34
19:24
8:03
21:26
. 9:10
9:41
10:32
9:54
11:37
13:29
18:04
9:15
15:09
5:38
17:06
23:43
4:10
13:35
18:14
10:22
12:20
11:13
6:19
13:00
13:19
Quant i tat ion
Ion
195
195
272
67/81
67
128
158
211/183
303/154
139
166
328
181
181
181
181
100
81
394/396
284
360
237
171
276
82
209/153
227
109
162
198
127
164/66
164
IS
Reference
#
' 2
2
2
2
2
1
1
1
2
3
1
-3 ••"'
1
2
2
2
2
• 2 :
3
1
2
1
2
3
1
2
3
2
2-
2
1
2
2
525.2-34
-------
TABLE 2.
DATA, QUANTITATION IONS. AND INTERNAL STANDARD REFERENCES FOR METHOD ANALYTES
• - — II
Compound
Retention
Time (min:sec)
Aa B"
molinate
napropamide
norflurazon .
2,2' ,3,3' ,4,5' ,6,6'-octachlorobiphenyl
pebulate
2,2',3',4,6-pentachlorobiphenyl
pentachlorophenol
permethrin, cis
permethrin, trans
phenanthrene
prometon
prometryn
pronamide
propachlor
propazine
pyrene
simazine
simetryn
stirofos
tebuthiuron
terbacil
terbufos
terbutryn
2,2',4,4'-tetrachlorobiphenyl
toxaphene
8:19
16:53
19:31
21 '33
7:18
15:37
11:01
24:25
24:39
11:41
10:39
13:15
11:19
9:00
10:54
16:41
10:41
13:04
16:20
8:00
11:44
11:14
13:39
14:02
triademefon I 14-30
2,4,5-trichlorobiphenyl
tricyclazole
trifluralin
vernolate
Single-ramp linear temperature program conditions
Multi-ramp linear temperature program conditions (J
12:44
17:15
9:31
7:30
14:37
16:46
18:11
6:40
13:33
9:45
20:01
20:10
10:16
9:32
. 11:39
10:02
8:07
9:43
9:33
11:29
14:11
7:16
10:24
9:58
11:58
12:14
13:00-21:00
12:40
10:53
14:51
8:37
7:10 I 6:32
[Sect. 10.2.3.2).
Sect. 10.2.3.1).
Quant i tat ion
Ion
126
145
430/428
128
183
183
178
225/168
241/184
173
120
214/172
201/186
213
109
156
161
226/185
292
159
IS
Reference
#
_
2
3
3
2
,
2
1
,
2
1
2
2
2-
?
57
189
306
128
. . '
2 II
~^H
-^— I
525.2-35
-------
TABLE 3 ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER
USING LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE QUADRUPOLE MASS SPECTROMETER
Compound
True
Cone.
C/ig/U
Mean
Observed
Cone .
(;ig/L)
Relative
Standard
Deviation
(%)
Mean Method
Accuracy
(% of True
Cone.)
MDL
(/ig/D
[.
Surrogates r
1,3-dimethyl-2-m'trobenzene
ucrylene-d12
triphenylphosphate
5.0
5.0
5.0
4.7
4.9
'• • 5.5
3.9
4.8
6.3
94
98
110
Target Analytes
acenaphthylene
alachlor
aldrin
ametryn
anthracene
Aroclor 1016
Aroclor 1221
Aroclor 1232
Aroctor 1242
Aroclor 1448
Aroclor 1254
Aroclor 1260
atraton4
atrazine
bcnz [a] anthracene
benzo [b] f luoranthene
benzo[g.h,i]perylene
bcnzo [a] pyrene
bromacil
butachlor
butylate
butylbenzylphthalate
carboxin
chlordane Calpha-chlordane)
chlordane (ganroa-chlordane)
0.50 :
0.50
0.50
0.50 '
0.50
ND-
ND
ND:
ND,
ND
ND;
ND
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
. 5.0
0.50
0.50
0.50
0.45
:o.47
0.40
: 0..44
0.53
' ND
ND
ND
• ND
ND
ND
. ND
0.35
0.54
0.41
0.49
0.51
0.72
0.58
0.54
0.62
0.52
0.77
3.8
0.36
0.40
0.43
8.2
12
9.3
6.9
' 4.3
ND
ND
ND
ND
ND
ND
ND
15
4.8
16
20
35
2.2
1.9
6.4
4.1
4.1
11
12
11
8.8
17
91
93
80
88
106
ND
ND
ND
ND
ND
ND
ND
70
109
82
98
102
144
116
108
124
105
154
76
72
80
87
0.11
0.16
0.11
0.092
0.068
ND
ND
ND
ND
ND
ND
ND
0.16
0.078
0.20
0.30
0.54
0.047
0.032
0.10
0.076
0.064
0.25
1.4
0.12
0.11
0.22' I
525.2-36
-------
TABLE 3. ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER USING
LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE QUADRUPOLE MASS SPECTROMETER
(CONTINUED) : :
Compound
True ;
Cone .
(/ig/L)
Mean
Observed
Cone.
(Jig/L)
Relative
Standard
Deviation
(%)
Mean Method
Accuracy
(% of True
Cone.)
chlorneb •
chlorobenzilate
2-chlorobiphenyl
chlorpropham
chlorpyrifos • :
chlorothaloni t
chrysene
cyanazine
cycloate
DCPA
4,4'-DDD
4,4'-DDE
4,4'-DDT •
diazinon
dibenz [a, h] anthracene
di-n-butylphthalate
2,3-dichlorobiphenyl
dichtorvos
dieldrin
di-(2-ethylhexyl)adipate
di'(2-ethylhexyl)phthalate
diethylphthalate
dimethylphthalate
2,4-dinitrotoluene
2,6-dinitrotoluene
diphenamid
disulfoton
disulfoton sulfone
disulfoton sulfoxide
endosulfan I
endosulfan II
endosulfan sulfate
0.50 '
• 5.0
0.50
0.50
0.50
0.50
0.50''
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50 '••
ND
0.50 :•
0.50 :
0.50
0.50
ND
0.50
0.50
0.50
o.so :
0.50-
5.0
0.50
0.50
0.50 '
0.50
0.50
0.51
6.5
0.40
0.61
0.55
0.57
0.39
0.71
0.52
0.55
0.54
0.40
0.79
0.41
^0.53
• ND
0.40
0.55
0.48
0.42
ND
0.59
• 0.60
0.60
0.60
0.54
3.99
0.74
0.58
0.55
0.50
0.62
5.7
6.9
7.2
6.2
2.7
6.9
7.0
8.0
6.1
5.8
4.4
6.3
3.5
8.8
0.5
ND
11
9.1
3.7
7.1
ND
9.6
3.2
5.6
8.8
2.5
5.1
3.2
12
18
29
7.2
102
130
80
121
110
113
78
141
104
109
107
80
159
85
106
ND
80
110
96
84
ND
118
120
119
121
107
80
148
116
110
99
124
MDL
C/ig/L)
0.088
1.3
0.086
0.11
0.044
0.12 .'
0.082
0.17
0.095
0.094
0.071
0.075
0.083 .
0.11 •
0.010 '
ND •
0.14
0.15
0.053
0.090-
ND
0.17
0.058
0.099.
0.16
0.041
0.62
0.070
0.20
0.30
0.44
0.13
525.2-37
-------
TABLE 3. ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER USING
LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE QUADRUPOLE MASS SPECTROMETER
(CONTINUED)
Compound
True
Cone.
Qtg/D
Mean
Observed
Cone'.
-------
TABLE 3.
ACCURACY AND PRECISION DATA FROH EIGHT DETERMINATIONS OF THE METHOD ANALYTES IM BPircuT uirro
(CONnNUEDUD C"18 CARTRIDGE EXTRACTI°N AND THE QUADRuPOLE MASS &CTROTCTER T "*"*
I Compound
2,2',3,3',4,5',6,6'-octachlorobiphenyl
pebulate
2,2',3',4,6-pentachlorobiphenyl
pentachlorophenol
permethrin, cis
permethrin, trans
phenathrene
prometon'
ppometryn
pronamide
propachlor
propazine
|| pyrene '
simazine
sfmetryn
stirofos : ' . :
II tebuthiuron
terbaci I
terbufos
terbutryn
2,2',4,4'-tetrachlorobiphenyl
toxaphene
- • — r—
tnademefon
2,4,5-trichlorobiphenyl
tricyclazole'
trifluraLin
vernolate
True
Cone.
(MA)
0.50
0.50
0.50
NO
0.25
0.75
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
5.0
5.0
0.50
0.50
0.50
NO
0.50
0.50
5.0
0.50
0.50
1
Mean
Observed
<£g/L)
Relative
Standard
{%)
0.50
0.49
0.30
, . ND
0.30
0.82
0.46
0.30
0.46
0.54
0.49
0.54
0.38
0.55
0.52
0.75
6.8
4.9
0.53
0.47
0.36
ND
0.57
0.38
4.6
0.63
0.51
== '
8.7
5 4
16
ND
Tt -7
2 7
4 3
42
5 6
5 9
•7 r
7.1
5.7
9.1
8.2
5.8
14 •
14
6.1
7 6
4.1
ND
20
6 7
19
5.1
5.5
====i=
Mean Method
Accuracy
<% of True
Cone.)
101
98
61
ND
121
109
92
60
108
98
108
109
105
149
136
97
106
95
71
113
92
127
102
MDL
Gig/D
0 38
0.12
0.066
0 13
2.8
0 33
o
0.096
0.084 1
ND = Not Determined
Data from samples extracted at pH 2 - for accurate determination of this analyte a
extracted at ambient pH. '
separate sample must be
525.2-39
-------
TABLE 4 ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER USING
LIQUID-SOLID C-18 DISK EXTRACTION AND THE QUADRUPOLE MASS SPECTROMETER
Compound
True
Cone.
-------
TABLE 4.
ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER USING
LIQUID-SOLID C-18 DISK EXTRACTION AND THE QUADRUPOLE MASS SPECTROMETER (CONTINUED)
• ' ' • ' • - : ' ' ~ ' I
Compound
True
Cone.
Otg/D
Mean
Observed
Cone.
Relative
Standard
Deviation
. {%)
Mean Method
Accuracy
(% of True
chlorneb
chlorobenzilate
2-chlorobiphenyl
chlorpropham
chlorpyrifos
chlorothaConi I
chrysene
cyanazine
cycloate
DCPA
4,4'-DDD
4,4'-DDE
4,4'-DDT
diazinon
dibenz [a, h] anthracene
di-n-butylphthalate
2,3-dichlorobiphenyl
dichlorvos
dieldrin
di - (H-ethylhexyl )adipate
di (2-ethylhexyl )phthalate
diethylphthalate
diniethylphthalate
2,4-dinitrotoluene
2,6-dini trotoluene
diphenamid
disulfoton
disulfoton sulfone
disulfoton sulfoxide
endosulfan I
endosulfan II
1 endosulfan sulfate
0.50
5.0
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
ND
0.50
0.50
0.50
ND
ND
0.50
0.50
0.50
0.50
0.50
5.0
0.50
0.50
0.50
0.50
0.50
0.51
7.9
0.42
0.68
0.61
0.59
0.35
0.68
0.53
0.55
0.67
0.48
0.93
0.56
0.61
ND
0.46
0.54
0.52
ND
ND
0.66
0.57
0.54
0.48
0.60
4.8
0.82
0.68
0.65
0.60
0.67
7.3
8.4
1.9
5.4
6.5
6.5
3.6
15
4.9
4.5
14
4.9
3.2
6.8
' 15
ND
8.1
5.6
7.8
ND
ND
10
8.3
5.7
4.9
3.8
9.4
2.8
8.9
10
21
6:1
100
156
84
134
119
116
71
136
106
110
137
96
187
109
122
ND
93
108
104
ND
ND
132
114
109
96
118
96
164
136
132
122
133
MDL
0.11
2.0
0.023
0.11
0.12
0.11-
0.038
0.31
0.077
0.073
0.28
0.070
0.090
0.11
0.28
ND
0.11
0.092
0.12
ND
ND
0.20
0.14
0.093
0.071
0.067
1.3
0.070
0.18
0.20
0.38
0.12
525.2-41
-------
TABLE 4 ACCURACY AND PRECISIOM DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER USING
UQUID-SOUD C-18 DISK EXTRACTION AND THE QUADRUPOLE MASS SPECTROMETER (CONTINUED)
Compound
True
Cone.
0.31
0.24
0.056
0.048
0.090
1.6
1.2
0.11
0.77
0.20
0.28
0.15
0.12
0.14
0.093
0.14
0.12
0.13
0.16
0.14
0.050
0.052
0.033
0.25
0.084
0.062
0.079
0.10
0.030
0.050
0.11
0.089
525.2-42
-------
TABLE 4.
ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER usrur
LIQUID-SOLID. C-18 DISK EXTRACTION AND THE QUADRUPOLE MASS SPECTROMETER (CONTINUED)
. II
Compound
2,2',3,3',4,5',6,6'-octachlorobiphenvl
pebulate
2,2',3',4,6-pentachlorobiphenyl
pentachlorophenol
permethrin.cis
permethrin, trans
phenathrene
prometon' ; ,
prometryn
pronamide
propachlor
propazine
pyrene
simazine
simetryn
stiro.fos
tebuthiuron
terbacit
terbufos
terbutryn
2,2' ,4,4' -tetrach lorobiphenyt
toxaphene
triademefon
2,4,5-trichlorobiphenyl
tricyclazole
trif luralin
vernolate
True
Cone.
Otg/U
0.50
0.50
0.50
2.0
0.25
0.75
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
5.0
5.0
0.50
0.50
0.50
NO
0.50
0.50
5.0
0.50
0.50
Mean
Observed
Cone.
Oig/D
Relative
Standard
(%)
0.51
0.48
0.35
1.9
0.32
0.89
0.48
0.21
0.46
0.58
0.49
0.59
0.40
0.60
0.41
0.84
9.3
5.0
0.62
0.46
0.40
ND
0.73
0.44
6.8
0.62
0.51
4.2
5.8
4.2
16
3.3
1.9
5.0
66
24
7.1
5.4
5.0
3.2
10
15
3.2
8.6
11
4.2
23
7.4
ND
7.2
5.3
12
2.6
Mean Method
Accuracy
(% of True
Cone.)
102
96
70
95
126
118
95
45
93
113
98
117
79
120
83
168
187
100
123
94
ND
145
89
137
124
HDL
(/tg/D
0.064
0.084
0.044
.89
0.031
0.051
0.071
0.44
0.33
0.12
0.079
0.088
0.038
' 0.18
0.19
0.081
1.7
0.077
0.32
0.088
ND
0.16
0.071
2.4
0.048
ND = Not Determined
Data from samples extracted at pH 2 - for accurate determination of this analyte a
extracted at ambient pH.
separate sample must be
525.2-43
-------
TABLE 5 ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER USING
LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE ION TRAP MASS SPECTROMETER
Compound
True
Cone.
C/ig/L)
Mean
Observed
Cone.
((ig/L)
Relative
Standard
Deviation
(%)
Mean Method
Accuracy
(% of True
Cone . )
MDL
C/ig/L >
Surrogates • r
1,3-dimethyl-2-mtrobenzene
perylene-d12
triphenylphosphate
5.0
5.0
5.0
4.9
4.3
4.8
8.4
18
13
98
86
96
Target Analytes T
acenaohthylene
alachlor
aldrin
amctryn
anthracene
Aroclor 1016
Aroclor 1221
Aroclor 1232
Aroclor 1242
Aroclor 1248
aroclor 1254*
aroclor 1260
atraton'
atrazine
bcnz ta] anthracene
benzo Cb] f luoranthene
bcnzo Ck] f luoranthene
benzo [g . h , i ] pery I ene
benzo [a] pyrene
bromaci I
butachlor
butyl ate
butylbenzylphthalate"
carboxin
chlordane, (alpha-chlordane)
chlordane, (gamma-chlordane)
chlordane, (trans-nonachlor)
0.50
0.50
0.50
0.50
0.50
1.0
ND
ND
ND
ND
1.0 ,
1.0
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
5.0
0.50
0.50
0.50
0.50
• 0.50
0.58
0.4H
0.46
0.42
1.1
ND
'ND
ND
ND
1.1
0.96
0.35
0.55
0.43
0.44
0.34
0.38
0.36
0.45
0.67
0.52
5.7
0.58
0.47
0.50
0.48
8.8
4.0
3.5
3.3
3.8
4.4
ND
ND
ND
ND
17
9.3
11
5.0
7.3
16
22
31
21
9.1
12
5.2
7.7
22
12
10
11
100
115
85
91
84
113
ND
ND
ND
ND
110
96
70
109
85
88
68
76
73
90
133
104
114
117
95
99
96
0.13
0.069
0.045
0.045
0.048
0.15
ND
ND
ND
ND
0.56
0.27
0.12
0.081
0.093
0.21
0.23
0.35
0.23
0.12
0.24
0.082
1.4
0.38
0.17
0.16
0.16
525.2-44
-------
TABLE 5. ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANAUTES IH REAGENT VATER USIWi
LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE ION TRAP MASS SPECTROMETER (CONTINUED)
I
Compound
True
Cone;
(/ig/L)
chlorneb
chlorobenzi late
2-ch lorobiphenyl
chlorpropham
chlorpyrifos
chlorothaloni I
chrysene
cyanazine
cycloate
DCPA
4,4'-DDD
4,4'-DDE
4,4'-DDT
diazinon
d ibenz [a, h] anthracene
di-n-butylphthalate"
2, 3 -dich lorobiphenyl
dichlorvos
dieldrin
di (2-ethy Ihexyl )adipate
di(2-ethylhexyl)phthalate"
diethylphthalate
dimethylphthalate
2,4-dinitrotoluene
2,6-dinitrotoluene
diphenamid
disulfoton
disulfoton sulfone
disulfoton sulfoxide
endosulfan I
endosulfan II
endosulfan sulfate
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
5.0
0.50
0.50
0.50
0.50
5.0
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
Mean
Observed
Cone .
C/ig/L)
0.51
0.61
0.47
0.55
0.50
0.62
0.50
0.49
0.52
.. 0.55
0.52
0.41
0.54
0.37
0.37
6.2
0.45
0.53
0.50
0.59
6.5
0.63
0.51
0.45
0.40
0.55
0.62
0.64
0.57
0.60
0.64
0.58
Relative
Standard
Deviation
<%>
Mean Method
Accuracy
(% of True
Cone . )
8.1
9.7 •
4.8
8.1
2.4
5.3
9.2
13
7.6
7.2
3.6
5.8
2.4
2.7
29
4.6
5.8
8.0
10
18
6.6
15
9.5
18
17
6.5
9.8
3.5
8.6
6.1
3.9
5.4
103
123
94
109
99
123
99
97
103
109
103
81
108
75
74
124
90
106
100
117
130
126
102
91
'80
111
124
128
114
121
128
116
HDL
-------
TABLE 5 ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER USING
LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE ION TRAP MASS SPECTROMETER (CONTINUED)
Compound
True
Cone.
-------
TABLE 5. ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANW.YTES IK REAGENT WATER
LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE ION TRAP MASS SPECTROMETER (CONTINUED}
Compound
2,2' ,3,3' ,4,5' ,6,6'-octachlorobiphenyl
pebulate
2,2' ,3' ,4,6-pentachlorobiphenyl
pentachlorophenol
pennethrin,cis
permethr in, trans
phenanthrene
prometon' . ',
prometryn
pronamide
propachlor
propazine
pyrene
simazine
simetryn
stirofos
tebuthiuron
terbacil
terbufos
terbutryn
2,2',4,4'-tetrachlorobiphenyl
toxaphene
triademefon
2,4,5- trichtorobiphenyl
tricyclazole
trifluralin
vernolate
True
Cone.
C/ig/L)
0.50
0.50
0.50
2.0
0.25
0.75
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50-
0.50
0.50
0.50
0.50
0.50
10
0.50
0.50
0.50
0.50
0.50
Mean
Observed
Cone.
-------
TABLE 6.
ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER USING
LIQUID-SOLID C-18 DISK EXTRACTION AND THE ION TRAP MASS SPECTROMETER
Compound
True
Cone.
(/tg/L)
Mean
Observed
Cone.
Surrogates
1,3-dfmethyl-2-nitrobenzene
perylene-d12
triphenylphosphate
5.0
5.0
5.0
4.9
4.9
5.9
10
4.5
8.1'
98
98
117
Target Analytes
acenaphthylene
alachlor
aldrin
ametryn
anthracene
Aroclor 1016
Aroclor 1221
Aroclor 1232
Aroclor 1242
Aroclor '248
Aroclor 1254
Aroclor 1260'
atraton"
atrazine
bcnz ta) anthracene
benzotbjfluoranthene
benzolk] f luoranthene
bcnzo[g,h,5]perylene
benzo [a] pyrene
bromacil
butachlor
butyl ate
butylbenzylphthalate0
carboxin
chlordane, (alpha-chlordane)
chlordane, (gamma-chlordane)
chlordane, (trans-nonachlor)
0.50
0.50
0.50
0.50
0.50
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
5.0
0.50
0.50
' 0.50
0.50
0.51
0.54
0.45
0.41
0.39
0.25
0.26
0.24
0.26
0.24
0.22
0.21
0.10
0.56
0.44
0.50
0.46
0.47
0.44
0.49
0.66
0.50
5.7
0.40
0.50
0.51
0.52
4.5
6.6
6.3
23
15
4.7
6.1
4.7
4.9
4.1
3.7
2.2
46
4.6
7.4
9.1
2.2
i 7.9
; 12
4.4
5.1
! 5.4
: 7.7
38.1
4.3
7.2
6.2
102
108
90
82
79
123
130
121
129
118
110
108
21
111
88
100
91
95
89
99
132
100
114
79
101
102
104
0.068
0.11
0.085
0.29
0.18
0.040
0.054
0.042
0.043
0.038
0.028
0.018
0.14
0.076
0.098
0.14
0.031
0.11
0.16
0.066
0.10
0.082
1.4
0.45
0.065
0.11
0.097
525.2-48
-------
TABLE 6. ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD•ANALYTES IN REAGENT WATER'USING
LIQUID-SOLID C-18 DISK EXTRACTION AMD THE ION TRAP MASS SPECTROMETER (CONTINUED)
Compound
True
Cone.
to/L)
Mean
Observed
Cone.
<^g/L) ...
Relative
Standard
Deviation
(%)
Mean Method
Accuracy
(% of True
Cone . )
MDL
Oig/L>
chlorneb
chlorobenzilate
2-chlorobiphenyl
chlorpropham
chlorpyrifos
chlorothaloni I
chrysene
cyanazine
cycloate
DCPA
4,4'-DDD
4, 4' -DDE
4,4'-DDT
diazinon
dibenz [a, h] anthracene
di-n-butylphthalate"
2,3-dichlorobiphenyl
dichtorvos
dieldrin
di (2-ethy Ihexyl )adipateB
di(2-ehtylhexyl)phthalate"
diethylphthalate
dimethylphthalate
2,4-dinitrotoluene
2,6-dinitrotoluene
diphenamid
disulfoton
disulfoton sulfone
disulfoton sulfoxide
endosutfan I
endosulfan II
endosulfan sulfate
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
5.0
0.50
0.50
0.50
5.0
5.0
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.54
0.59
0.50
0.55
0.54
0.59
0.48
0.52
0.51
0.53
0.63
0.48
0.58
0.50
0.47
5.7
0.50
0.50 .
0.53
5.4
5.7
0.68
0.51
0.30
0.28
0.56
0.70
0.64
. 0.60
0.61
0.66
0.57
6.3
9.7
4.7
4.7
11
4.4
6.1
8.3
4.1
3.2
16
3.7
7.2
4.5
9.9
3.3
2.6
8.7
7.0
7.5
2.6
5.0
5.0
8.1
6.4
6.4
5.3
5.9
3.8
4.9
6.1
9.0
108
117
100
111
109
119
96
105
102
105
127
96
117
101
94
115
100
99
106
107
114
137
102
59
56
112
139
128
119
122
131
115
0.10
0.17
0.070
0.079
0.18
0.079
0.088
0.13
0.063
0.051
0.31
0.054
0.13
0.068
0.14
0.59
0.039
0.13
0.11
1.3
0.46
0.10
0.077
0.072
0.054
0.11
0.11
0.11
0.068
0.089
0.12
0.16
525.2-49
-------
TABLE 6.
ACCURACY AND PRECISION DATA FROM EIGHT DETERMINATIONS OF THE METHOD ANALYTES IN REAGENT WATER USING
LIQUID-SOtID C-18 DISK EXTRACTION AND THE ION TRAP MASS SPECTROMETER (CONTINUED)
• -
Compound
endrfn
cndrin aldehyde
EPTC
cthoprop
etridiazole
fenacniphos
fcnarlmol
fluorane
fturidone
HCH, alpha
HCH, beta
HCH, delta
HCH, garama (lindane)
hcptachlor
hcptachlor epoxide
2,2',3,3',4,4',6-heptachlorobipheny
I
hcxach lorofaenzene
2,2',4,4',5,6'-hexachlorobiphenyl
hexach lorocyc I opentadi ene
hexazinone
{ndenoC1,2,3-cd]pyrene
isophorone
mcthoxychlor
methyl paraoxon
mctolachlor
metribuzin
mrvinphos
HuK 264 • isomer a
HGK 264 - isomer b
molinate
napropamide
norflurazon
True
Cone.
(M/L)
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0,50 -•
5.0
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.33
, 0.16
0.50
0.50
' 0.50
Mean
Observed
Cone.
(jig/D
0.68
0.57
0.48
0.61
0.54
0.67
0.59
0.53
5.2
Q.55
0.54
0.53
0.50
0.49
0.50
0.46
0.49
0.50
0.37
0.75
0.48
0.51
0.52
0.75
0.57
0.53
0.56
0.38
0.18
0.53
0.58
0.71
Relative
' Standard
: Deviation
C%)
7.9
2.8
5.2
.:•• 7.5
4.2
10
5.8
•i • 3.4
2.3
5.0
4.1
3.6
3.2
4.0
. 3.2
I
• 7.3
3.4
1 5.3
9.3
4.2
7.3
i 4.3
6.7
.4.5
3.2
5.7
6.2
6.7
5.3
3.8
7.9
4.3
Mean Method
Accuracy
(% of True
Cone.)
137
114
97
122
108
133
118
• 106
104
110
109
106
100
98
100
• • 92
97
99
73
150
96
102
104
151
114
107
112
113
110
105
116
142
MDL
Oig/L)
0.16
0.048
0.076
0.14
0.067
0.20
0.10
0,054
0.16
0.083
0.068
0.058
0.047
0.059
0.048
0.10
0.049
0.079
0.10
0.094
0.10
0.066
0.10
0.10
0.054
0.090
0.10
0.076
0.029
0.060
0.14
0.091
525.2-50
-------
TABLE 6.
ACCURACY: AND PRECISION DATA FROM EIGHT DETERMINATIONS OF. THE METHOD ANALVTES IN REAGENT WATER USING
LIQUID-SOLID C-18 DISK EXTRACTION AND THE ION TRAP MASS SPECTROMETER (CONTINUE0)
Compound
2,2',3,3',4,5',6,6'-
octachlorobiphenyl
pebulate
2,2' ,3' ,4,6-pentachlorobiphenyl
pentachlorophenol
permethrin,cis
permethrin, trans
phenanthrene
prometon"
prometryn
pronamide '
propachlor
propazine
pyrene
simazine
simetryn
stirofos
tebuthiuron
terbaci I
terbufos
terbutryn
2,2',4,4'-tetrachlorobiphenyl
toxaphene'
triademefori
, 2,4,5-trichlorobiphenyt
tricyclazole
trifluralin
vernolate
True
Cone.
Oig/U
Mean
Observed
Cone.
(jitg/L)
Relative
Standard
(%)
Mean Method
Accuracy
(% of True
0.50
0.50
0.50
2.0
0.25
0.75
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50 '
0.50
. 0.50
0.50
0.50
.10
0.50
0.50-
0.50
0.50
0.50
0.47 '
0.56
0.49
2.2
0.37
0.84
0.49
0.16
0.46
0.56
0.58
0.53 ,
0.52
0.54
, 0.36 ,
0.72
0.67
0.64
0.57
0.46
0.46
12
0.71
0.48
0.65
0.59
0.50
5.3
7.1
4.0
15
3.1
1.6
6.3
63
23
3.9
5.7
4.7
5.2
2.8
20
3.7
7.9
12
6.8
24
7.4
2.7
7.3
4.5
14
7.8 .
3.2
94
112
97
111
149
112
97
32
91
111
115
106
104
107
, 71 :
144
133
129
113
93
91
122
142
97
130
117
99
.)
MDL
(^9/L)
0.076
0.11
0.059
1.0
0.035
0.039
0.092
0.30
0.32
0.064
0.098
0.074
0.080
0.045
0.22
0.080
0.16
0.23
0.11
Oi34
0.10
1.0
0.16
0.066
0.27
0.14
Six replicates
Seven replicates in fortified tap water. ' *
Seven replicates
Data from samples extracted at pH 2 - for accurate determination of this analyte. a separate sample must be
extracted at ambient pH. •
525.2-51
-------
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525.2-52
-------
TABLE 8.
ACCURACY AND PRECISION DATA FROM SEVEN DETERMINATIONS OF THE METHOD ANALYTES [H
TAP WATER USING LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE ION TRAP MASS
SPECTROMETER ;
Compound
acenaphthylene
alachlor
aldrin
ametryn
anthracene
Aroclor 1016
Aroclor 1221
Aroclor 1232
Aroctor 1242
Aroclor 1248
APbclbr 1254
Aroclor 1260 . , , -'....
atraton'
atrazine
benz [a] anth racene
benzo[b]f luoranthene
t-:nzo[k]f luoranthene
benzo[g,h,i]perylene
benzo Ca] pyrene
bromacil
butachlor
butyl ate . . :
butylbenzylphthalate
carboxin
chlordane, (alpha-chlordane)
chlordane, (gamma-chlordane)
chlordane, (trans-nonachlbr)
chlorneb
chlorobenzi late
2Jchlorobiphenyl
chlorpropham
chlorpyrifos
chlorthalonil
chrysene
True Cone*
5.0
5.0
5.0
5.0
5.0
ND
ND
ND
ND
ND
. ' ND
ND
• . 5.0 •
5.0
' 5.0.
'S.O
5.0
'5.0
5.0
5.0
5.0
5.0
5.0
5.0
'5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
Mean
5.2
5.5 „
4.4
4.2
4.3
ND
ND
ND
ND
ND
ND
ND
2.2 ,
5.6
4.9
5.7
5.7
5.6
6.1
3.5
5.4
5.1
7.2
1.0
5.2
5.1
5.6
5.2
5.7 ;
5.8
6.3
5.3
5.4
5.5
% RSD
.'.-
5.3
6.9
14
3.4
5.2'
ND
ND
ND
ND
ND
ND
• ND
28
6.2
8.8
7.5
2.9
7.1
4.6 .
5.1
'7.5
4.5 •;
8.3
23
8.9
8.0
7.4
3.0 '
4.4
5.4
4.9
7.2
9.9
3.9
% REC
104
110
88
83
87
ND
. ND
ND
ND
ND
ND
ND
43
111
97
114
113
113
121
69
109
102
144
20
104
102
111
105
114
115
127
107
108
110
525.2-53
-------
TABLE 8. ACCURACY AND PRECISION DATA FROM SEVEN DETERMINATIONS OF THE METHOD ANALYTES IN TAP WATER
USING LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE ION TRAP MASS SPECTROMETER (CONTINUED)
Compound
cyanazine
cycloate
DCPA
4,4'-DDD
4,4'-DDE
4,4'-DDT
diazinon
dibenz [a, h] anthracene
di-n-butylphthalate
2,3-dichlorobiphenyl
dichlorvos
dietdrin
di (2-ethylhexyl )adipate
di(2-ethylhexyl)phthalate
diethytphthalate
dfmethylphthalate
2,4-dinitrotoluene
2,6-dinitrotoluene
diphenamid
disutfoton
disulfoton sulfone
disulfoton su If oxide
endosulfan I
endosulfan II
endosulfan sulfate
endrin
endrin aldehyde
EPTC
ethoprop
etrfdiazole
fenamfphos
fenarimol
f luorene
fluridone
HCH, alpha
True Cone.
5.0
5.0 •
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0;
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
s;o
s.o ;
Mean
6.1
5.6
5.4
5.3
5.2
5.6
4.9
5.9
6.2
5.3
2.8
5.3
6.7
6.5
6.4
5.8
4.2
4.1
5.2
2.5
5.5
9.4
5.5
5.3
5.3
6.1
5.1
5.1
6.3
5.8
5.9
7.1
5.7
6,2
5.9
% RSD
13
1.5
5.0
6.5
6.6
9.6
8.7
7.5
4.6
7.4
7.3
1 7.2
10
6.6
7.4
7.1
8.7
8.5
7.7
33
7.4
11
11
9.6
7.8
3.9
9.1
2.1
4.2
7.5
22
3.3
5.2
9.0
2.6
% REC
122
112
107 .
105
104
111
98
118
124
106
56
105
134
130
. 127
116
84
82
104
50
110
188
109
106
106
121
102
102
125
117
119
141
114
125
118
525.2-54
-------
TABLE 8. ACCURACY AND PRECISION DATA FROM SEVEN DETERMINATIONS OF THE METHOD ANALYTES IN TAP UATEK
USING LIQUID-SOLID C-18 CARTRIDGE EXTRACTiON AND THE ION TRAP MA'SS SPECTROMETER (CONTINUED)
Compound
HCH, beta
HCH, delta
HCH, gamma (Lindane)
heptachlor
heptachlor epoxide
2,2' ,3,3' ,4,4' ,6-heptachlorobiphenyl
hexach I orobenzene
2,2',4,4',5,6'-hexachlorobiphenyl
hexachlorocyclopentadiene •
hexazinone
i ndeno [ 1 , 2 , 3 - cd] py rene
isophorone
methoxychlor
methyl paraoxon
;
metolachlor
metribuzin •
mevinphos
MGK 264 - isomer a
MGK 264 - isomer b
molinate
napropamide
norf turazon '.
2,2',3,3',4,5',6,6'-octactorobiphenyl
pebulate
2,2' ,3',4,6-pentachlorobiphenyl
pentach I oropheno I
permethrin, cis
permethrin, trans
phenanthrene
prometona*.
prometryn
pronamide
propachlor
propazine
pyrene
True Cone.
5.0
5.0
5.0
5.0
•• 5.0
5.0
5.0
5.0
5.0 .
5.0
5:0
5.0
- 5.0
5.0
5.0
5.0
5.0
3.3
1.7
5.0
5.0
-5.0
5;0
• 5.0
5.0
20.
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0 .•
5.0
Mean
5.3
5.3
5.3
4.7
5.2
5.1
4.6
5.6
6.0
6.9
6.8
4.9
5.6
5.6
5.6
2.1
3.3
3.6
1.8
5.5
5.3
6.7
4.9
5 .3
5.3
33
3.3
8.5
5.5
2.0
4.5
5.7
6.2
5.6
5.2
% RSD
8.4
5.2
6.9
8.7
. 7.7
6.9
7.4
8.1
4.8
6.3
7.7
12
4.9
11
7.7
5.8
1.6
6.2
7. -6
1.5
8.9
7.2
6.9
3.1
8.1
4.9
3.5
2.2
4.0
25
4.3
5.3
4.0
4.9
6.7
% REC
106
106
107
93
105
. 103
93
112
120
138
135
99
112
111
111
42
67
107
110
, 110
106
135
97
106
107
162
130
113
109
40
89
115
124
' 113
104
525.2-55
-------
TABLE 8.
ACCURACY AND PRECISION DATA FROM SEVEN DETERMINATIONS OF THE METHOD ANALYTES IN TAP WATER
USING LIQUID-SOLID C-18 CARTRIDGE EXTRACTION AND THE ION TRAP MASS SPECTROMETER (CONTINUED)
•
Compound
simazine
simetryn
stirofos
tebuthiuron
terbaci I
terbufos
terbutryn
2,2',4,4'-tetrachlorobiphenyl
toxaphene
triademefon
2,4,5-trichlorobiphenyl
tricyclazole
trif lutelin
vernotate
True Cone.
5.0
5.0
5.'o
5:0
5.0
5 JO
5.0
5.0
i,ND
5 JO
5 Jo
5.0
5JO
5JO
Mean
6.0
3.9
6.1
6.5
4.0
4.5
4.3
5.3
ND
6.0
5.2
4.8
5.9
5.4
% RSD
9.0
7.0
12
9.7
5.5
8.4
6.5
4.3
ND
12
5.1
5.2
7.8
3.3
% REC
120
78
121
130
79
90
86
106
ND
121
103
96
119
108
Data from samples extracted at pH 2 - for accurate determination of this analyte, a separate sample
must be extracted at ambient pH.
525.2^56
-------
2 Liter
separator/
funnel
K3
125ml
solvent
reservoir
ground glass T 14/35
IS£ cartridge
J y rubber stopper
No. 18-2O tuer-lok
syringe needle
1 fiter
vacuum flask
125 ml
solvent
reservoir
ground glass
I 14/35
ISE cartridge
10Oml
separator/
funnel
drying
column
(Na,SOJ
0.6 cm x 4O cm
1O ml
f graduated
I vial
A. Extraction apparatus
B. Etutlon apparatus
FIGURE 1. CARTRIDGE EXTRACTION APPARATUS
525.2-57
-------
525.2-58
-------
METHOD 531.1. MEASUREMENT OF N-METHYLCARBAMOYLOXIMES AND N-METHYLCARBAMATES
IN WATER BY DIRECT AQUEOUS INJECTION HPLC WITH POST COLUMN
DERIVATIZATION
Revision 3.1
Edited by J.W, Munch (1995)
D.L. Foerst - Method 531, Revision 1.0 (1985)
T. Engel (Battelle Columbus Laboratories) - National Pesticide Survey
Method 5, Revision 2.0 (1987)
R.L.. Graves - Method 531.1, Revision 3.0 (1989)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
531.r-i
-------
METHOD 531.1
MEASUREMENT OF N-METHYLCARBAMOYLOXIMES
AND N-METHYLCARBAMATES IN WATER BY DIRECT AQUEOUS INJECTION HPLC
WITH POST COLUMN DERIVATIZATION
1. SCOPE AND APPLICATION
1.1 This is a high performance liquid chromatographic (HPLC) method
applicable to the determinations of certain N-methylcarbamoyloximes
and N-methylcarbamates in ground water and finished drinking water.
The following compounds can be determined using this method:
Chemical Abstract Services
Analvte Registry Number
Aldicarb 116-06-3
Aldicarb sulfone \ 1646-88-4
Aldicarb sulfoxide . 1646-87-3
Baygon 114-26-1
Carbaryl 63-25-2
Carbofuran 1563-66-2
3-Hydroxycarbofuran 16655-82-6
Methiocarb 2032-65-7
Methomyl 16752-77-5
Oxamyl . . 23135-22-0
1.2 This method has been validated in a single laboratory and estimated
detection limits (EDLs) and method detection limits (MDLS) have been
determined for the analytes above. Observed detection limits may
vary between ground waters, depending upon the nature of
interferences in the sample matrix and the specific instrumentation
used.
1.3 This method is restricted to use by or under the supervision of
analysts experienced in the use of liquid chromatography and in the
interpretation of liquid chromatograms. Each analyst must demon-
strate the ability to generate acceptable results with this method
using the procedure described in Sect. 9.3.
1.4 When this method is used to analyze unfamiliar samples for any or
all of the analytes above, analyte identifications should be
confirmed by at least one additional qualitative technique (1).
2. SUMMARY OF METHOD ;
2.1 The water sample is filtered and a 400-/zL aliquot is injected into a
reverse phase HPLC column. Separation of the analytes is achieved
using gradient elution chromatography. After elution from the HPLC
column, the analytes are hydrolyzed with 0.05 N sodium hydroxide
(NaOH) at 95°C. The methyl amine formed during hydrolysis is
531.1-2
-------
reacted with o-phthalaldehyde (OPA) and 2-mercaptoethanol to form a
highly fluorescent derivative which is detected by a fluorescence
detector (2). Analytes are quantitated using procedural standard
calibration (Sect. 3.14)
3. DEFINITIONS
3.1 INTERNAL STANDARD — A pure analyte(s) added to a solution in known
amount(s) and used to measure the relative responses of other method
analytes and surrogates that are components of the same solution.
The internal standard must be an analyte that is not a sample-
component.
3.2 SURROGATE ANALYTE — A pure analyte(s), which is extremely unlikely
to be found in any sample, and which is added to a sample aliquot in
known amount(s) before extraction and is measured with the same
procedures used to measure other sample components. The purpose of
a surrogate analyte is to monitor method performance with each
sample.
3.3 LABORATORY DUPLICATES (LD1 and LD2) — Two sample aliquots taken in
the analytical laboratory and analyzed separately with identical
procedures. Analyses of LD1 and LD2 give a measure of the precision
associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures.
3.4 FIELD DUPLICATES (FD1 and FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as well as with
laboratory procedures.
3.5e LABORATORY REAGENT BLANK (LRB) — An aliquot of reagent water that
is treated exactly as a sample including exposure to all glassware,
equipment, solvents, reagents, internal standards, and surrogates
that are used with other samples. The LRB is used to determine if
method analytes or other interferences are present in the laboratory
environment, the reagents, or the apparatus.
3.6 FIELD REAGENT BLANK (FRB) — Reagent water placed in a sample
container in the laboratory and treated as a sample in all respects,
including exposure to sampling site conditions, storage,
preservation and all analytical procedures. The purpose of the FRB
is to, determine if method analytes or other interferences are
present in the field environment.
3.7 LABORATORY PERFORMANCE CHECK SOLUTION (LPC) — A solution of method
analytes, surrogate compounds, and internal standards used to
evaluate the performance of the instrument system with respect to a
defined set of method criteria.
531.1-3
-------
3.8 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water to
which known quantities of the method analytes are added in the
laboratory." The LFB is analyzed exactly like a sample, and its
purpose is to determine whether the methodology is in control, and
whether the laboratory is capable of making accurate and precise
measurements at the required method detection limit.
3.9 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
3.10 STOCK STANDARD SOLUTION — A concentrated solution containing a
single certified standard that is a method analyte, or a
concentrated solution of a single analyte prepared in the laboratory
with an assayed reference compound. Stock standard solutions are
used to prepare primary dilution^ standards.
3.11 PRIMARY DILUTION STANDARD SOLUTION — A solution of several analytes
prepared in the laboratory from stock standard solutions and diluted
as needed to prepare calibration1 solutions and other needed analyte
solutions. • •- . '
3.12 CALIBRATION STANDARD (CAL) — A solution prepared from the primary
dilution standard solution and s[tock standard solutions of the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration.
3.13 QUALITY CONTROL SAMPLE (QCS) — A sample matrix containing,method
analytes or a solution of method analytes in a water miscible
solvent which is used to fortify reagent water or environmental
samples. The QCS is obtained from a source external to the
laboratory, and is used to check laboratory performance with
externally prepared test materials.
3.14 PROCEDURAL STANDARD CALIBRATION — A calibration method where
aqueous calibration standards are prepared and processed (e.g.
purged, extracted, and/or derivajtized) in exactly the same manner as
a sample. All steps in the process from addition of sampling
preservatives through instrumental analyses are included in the
calibration. Using procedural standard calibration compensates for
any inefficiencies in the processing procedure.
4. INTERFERENCES
4.1 Method interferences may be caused by contaminants in solvents,
reagents, glassware and other sample processing apparatus that lead
531.1-4
-------
to discrete artifacts or elevated baselines in liquid chromatograms.
Specific sources of contamination have not been identified. All
reagents and apparatus must be routinely demonstrated to be free
from interferences under the conditions of the analysis by running
laboratory reagent blanks as described in Sect. 9.2.
4.1.1
4.1.2
Glassware must be scrupulously cleaned.(3) Clean all
glassware as soon as possible after use by thoroughly rinsing
with the last solvent used in it. Follow by washing with hot
water and detergent and thorough rinsing with tap and reagent
water. Drain dry, and heat in an oven or muffle furnace at
40CTC for 1 hour. Do not heat volumetric glassware.
Thermally stable materials might not be eliminated by this
treatment. Thorough rinsing with acetone may be substituted
for the heating. After drying.and cooling, seal and store
glassware in a clean environment to prevent any accumulation
of dust or other contaminants. Store inverted or capped with
aluminum foi1.
The use of high purity reagents and solvents helps to
minimize interference problems. Purification of solvents by
distillation in all-glass systems may be required. WARNING:
When a solvent is purified, stabilizers added by the
manufacturer are removed, thus potentially making the solvent
hazardous. Also, when a solvent is purified, preservatives
added by the manufacturer are removed, thus potentially
reducing the shelf-life.
.2 Interfering contamination may occur when a sample containing
concentrations of analytes is analyzed immediately following
sample containing relatively high ,concentrations of analytes
preventive technique is between-sample rinsing of the sample
and filter holder with two portions of reagent water. After
analysis ,of a sample containing high concentrations of analytes,
or more laboratory reagent blanks should be analyzed.
low
a
A
syringe
one
4.3 Matrix interference may be caused by contaminants that are present
in the.sample. The extent of matrix interference will vary consid-
erably from source to source, depending upon the water sampled.
Analyte identifications must be confirmed. Positive identification
may be made by the use of an alternative detector which operates on
.. a chemical/physical principle different from that originally used;
e.g., mass spectrometry, or the use of a second chromatography
column. A suggested alternative column is described in Sect. 6.6.3.
5. SAFETY
5.1
The toxicity or carcinogenicity of each reagent used in this method
has not been precisely defined; however, each chemical compound must
be treated as a potential health hazard. Accordingly, exposure to
these chemicals must be reduced to the lowest possible level. The
laboratory is responsible for maintaining a current awareness file
531.1-5
-------
of OSHA regulations regarding the safe handling of the chemicals
specified in this method. A reference file of material safety data
sheets should also be made available to all personnel involved in
the chemical analysis. Additional references to laboratory safety
are available and have been identified (4-6) for the information of
the analyst.
5.2 WARNING: When a solvent is purified, stabilizers added by the
manufacturer are removed, thus potentially making the solvent
hazardous. ;
EQUIPMENT AND SUPPLIES (All specifications are suggested. Catalog
numbers are included for illustration only.)
6.1 SAMPLING EQUIPMENT '.
6.1.1 Grab sample bottle — 60-mt screw cap vials (Pierce No. 13075
or equivalent) and caps equipped with a PTFE-faced silicone
septa (Pierce No. 12722 or equivalent). Prior to use, wash
vials and septa as described in Sect. 4.1.1.
6.2 BALANCE — Analytical, capable of accurately weighing to the nearest
0.0001 g.
6.3 FILTRATION APPARATUS
6.3.1 Macrofiltration — To filter derivatization solutions and
mobile phases used in HPLC. Recommend using 47 mm filters
(Mi Hi pore Type HA, 0.45 pm for water and Mi Hi pore Type FH,
0.5 /im for organics or equivalent).
6.3.2 Microfiltration — To filter samples prior to HPLC analysis.
Use 13 mm filter holder (Millipore stainless steel XX300/200
or equivalent), and 13 mm diameter 0.2 p.m polyester filters
(Nuclepore 180406 or equivalent).
6.4 SYRINGES AND SYRINGE VALVES
6.4.1 Hypodermic syringe — 10-mL glass, with Luer-Lok tip.
6.4.2 Syringe valve — 3-way (Hamilton HV3-3 or equivalent).
6.4.3 Syringe needle — 7 to 10-cm long, 17-gauge, blunt tip.
6.4.4 Micro syringes — various
6.5 MISCELLANEOUS
sizes.
6.5.1 Solution storage bottles — Amber glass, 10- to 15-mL
capacity with TFE-fluorocarbon-lined screw cap.
6.5.2 Helium, for degassing solutions and solvents.
531.1-6
-------
6.6 HIGH PERFORMANCE LIQUID CHROMATOGRAPH (HPLC)
6.6.1 HPLC system capable of injecting 200- to 400-juL aliquots, and
performing binary linear gradients at .a constant flow rate.
A data system is recommended for measuring peak areas. Table
1 lists retention times observed for method analytes using
the columns and analytical conditions described below.
6.6.2 Column 1 (Primary column) — 150 mm long x 3.9 mm I.D.
stainless steel packed with 4 /mi NovaPak CIS. Mobil Phase is
established at 10:90 methanol:water, hold 2 min., then
program as a linear gradient to 80:20 methanol:water in 25
min. Alternative columns may be used in accordance with the
provisions described in Sect. 9.4.
6.6.3 Column 2 (Alternative column)* — 250 mm long x 4.6 mm I.D.
stainless steel packed with 5 /im Beckman Ultrasphere ODS.
Mobile phase is established at 1.0 mL/min as a linear
gradient from 15:85 methanol:water to 100 % methanol in 32
min. Data presented in this method were obtained using this
column. * Newer manufactured columns have not been able to
resolve aldicarb sulfone from oxamyl.
6.6.4 Column 3 (Alternative column) — 250 mm long x 4.6 mm I.D.
stainless steel packed with 5 jLim Supelco LC-1. Mobile phase
is established at 1.0 mL/min as a linear gradient from 15:85
methanol:water to 100 % methanol in 32 min.
6.6.5 Post column reactor — Capable of mixing reagents into the
mobile phase. Reactor should be constructed using PTFE
tubing and equipped with pumps to deliver 0.1 to 1.0 mL/min
of each reagent; mixing tees; and two 1.0-mL delay coils, one
thermostated at 95°C (ABI URS 051 and URA 100 or equivalent).
6.6.6 Fluorescence detector — Capable of excitation at 330 nm
(nominal) and detection of emission energies greater than 418
nm. A Schoffel Model 970 fluorescence detector was used to
generate the validation data presented in this method.
REAGENTS AND STANDARDS — WARNING: When a solvent is purified,
stabilizers added by the manufacturer are removed, thus potentially
making the solvent hazardous. Also, when a solvent is purified,
preservatives added by the manufacturer are removed, thus potentially
reducing the shelf-life.
7.1 REAGENT WATER — Reagent water is defined as water that is
reasonably free of contamination that would prevent the
determination of any analyte of interest. Reagent water used to
generate the validation data in this method was distilled water
obtained from the Magnetic Springs Water Co., 1801 Lone Eagle St.,
Columbus, Ohio 43228.
531.1-7
-------
7.2 METHANOL — Distilled-in-glass quality or equivalent.
7.3 HPLC MOBILE PHASE
7.3.1 Water — HPLC grade (available from Burdick and Jackson).
7.3.2 Methanol — HPLC grade. Filter and degas with helium before
use.
7.4 POST COLUMN DERIVATIZATION SOLUTIONS
7.4.1 Sodium hydroxide, 0.05 N — Dissolve 2.0 g of sodium
hydroxide (NaOH) in reagent.water. Dilute to 1.0 L with
reagent water. Filter and degas with helium just before use.
7.4.2 2-Mercaptoethanol (1+1) — Mix 10.0 mL of 2-mercaptoethanol
and 10.0 mL of acetonitrile. Cap. Store in hood (CAUTION —
stench).
7.4.3 Sodium borate (0.05 N) — Dissolve 19.1 g of sodium borate
(Na2B407 ' 10H20) in reagent water. Dilute to 1.0 L with
reagent water. The sodium borate will completely dissolve at
room temperature if prepared a day before use.
7.4.4 OPA reaction solution — Dissolve 100 + 10 mg of o-phthal-
aldehyde (mp 55-58°C) in 10 mL of methanol. Add to 1.0 L of
0.05 N sodium borate. Mix, filter, and degas with helium.
Add 100 juL of 2-mercaptoethanol (1+1) and mix. Make up fresh
solution daily.
7.5 MONOCHLOROACETIC'ACID BUFFER (pH3) — Prepare by mixing 156 mL of
2.5 M monochloroacetic acid and 100 mL 2.5 M potassium acetate.
7.6 4-BROMO-3,5-DIMETHYLPHENYL N-METHYLCARBAMATE (BDMC) — 98% purity,
for use as internal standard (available from Aldrich Chemical Co.).
7.7 STOCK STANDARD SOLUTIONS (1.00 /tg/jil) — Stock standard solutions
may be purchased as certified solutions or prepared from pure
standard materials using the following procedure:
7.7.1 Prepare stock standard solutions by accurately weighing
approximately 0.0100 g of pure material. Dissolve the
material in methanol and dilute to volume in a 10-mL
volumetric flask. Larger volumes may be used at the
convenience of the analyst. If compound purity is certified
at 96% or greater, the weight may be used without correction
to calculate the concentration of the stock standard.
Commercially prepared stock standards may be used at any
concentration if they are certified by the manufacturer or by
an independent source.
531.1-8
-------
7.7.2 Transfer the stock standard solutions into TFE-fluoro-
carbon-sealed screw cap vials. Store at room temperature and
protect from light.
7.7.3 Stock standard solutions should be replaced after two months
or sooner if comparison with laboratory fortified blanks, or
- • , QC samples indicate a problem.
7.8 INTERNAL STANDARD S9LUTION - Prepare an internal standard
fortification solution by accurately weighing approximately 0 0010 q
of pure BDMC. Dissolve the BDMC in methanol and dilute to volume in
a 10-mL volumetric flask. Transfer the internal standard
fortification solution to a TFE-fluorocarbon-sealed screw cap bottle
and store at room temperature. Addition of 5 pi of the internal
standard fortification solution to 50 ml of sample results in a
final internal standard concentration of 10 /zg/L. Solution should
be replaced when ongoing QC (Sect. 9) indicates a problem. Note:
BDMC has been shown to be an effective internal standard for the
method analytes, but other compounds may be used, if the quality
control requirements in Sect. 9 are met.
7.9 LABORATORY PERFORMANCE CHECK'SOLUTION - Prepare concentrate by
adding 20 pL of the 3-hydroxycarbofuran stock standard solution,
1.0 mL of the aldicarb sulfoxide stock standard solution, 200 #L of
the methiocarb stock standard solution, and 1 mL of the internal
standard fortification solution to a 10-mL volumetric flask. Dilute
to volume with methanol. Thoroughly mix concentrate. Prepare check
solution by placing 100 ./iL of the concentrate solution into a 100-mL
volumetric flask. Dilute to volume with buffered reagent water
Transfer to a TFE-fluorocarbon-sealed screw cap bottle and store at
room temperature. Solution should be replaced when ongoing QC
(Sect. 9) indicates a problem.
8. SAMPLE COLLECTION. PRESERVATION AND HANDLING
8.1 Grab samples must be collected in glass containers. Conventional
sampling practices (8) should be followed; however, the bottle must
not be prerinsed with sample before collection.
8.2 SAMPLE PRESERVATION/PH ADJUSTMENT - Oxamyl, 3-hydroxycarbofuran,
aldicarb sulfoxide, and carbaryl can all degrade quickly in neutral
and basic waters held at room temperature. (6,7) This short term
degradation is of concern during the time samples are being shipped
and the time processed samples are held at room temperature in
autosampler trays. Samples targeted .for the analysis of these three
analytes must be preserved at pH 3. The pH adjustment also
minimizes analyte biodegradation.
8.2.1 Add 1.8 mL of monochloroacetic acid buffer to the 60-mL
sample bottle. Add buffer to the sample bottle at the
sampling site or in the laboratory before shipping to the
sampling site.
531.1-9
-------
8.2.2 If residual chlorine is present, add 80 mg of sodium thio-
sulfate per liter of sample to the sample bottle prior to
collecting the sample.
8.2.3 After sample is collected in bottle containing buffer, seal
the sample bottle and shake vigorously for 1 min.
8.2.4 Samples must be iced or refrigerated at 4°C from the time of
collection until analysis is begun. Although preservation
results of up to 28 days indicate method analytes are not
labile in water samples when sample pH is adjusted to 3 or
less, and samples are shipped and stored at 4°C, analyte
lability may be affected by the matrix. Therefore, the
analyst should verify that the preservation technique is
applicable to the samples ;under study.
9. QUALITY CONTROL
9.1 Minimum quality control (QC) requirements are initial demonstration
of laboratory capability, monitoring internal standard peak area or
height in each sample and blank (when internal standard calibration
procedures are being employed), analysis of laboratory reagent
blanks, laboratory fortified samples, laboratory fortified blanks
and QC samples. A MDL for each analyte must also be determined.
9.2 LABORATORY REAGENT BLANKS. Before processing any samples, the
analyst must demonstrate that all glassware and reagent
interferences are under control. Each time a set of samples is
extracted or reagents are changed, a laboratory reagent blank (LRB)
must be analyzed. If within the retention time window of any
analyte of interest the LRB produces a peak that would prevent the
determination of that analyte, determine the source of contamination
and eliminate the interference before processing samples.
9.3 INITIAL DEMONSTRATION OF CAPABILITY.
9.3.1 Select a representative concentration, about 10 times EDL, or
a concentration that represents a medium concentration
calibration standard for each analyte. Prepare a primary
dilution standard (in methanol) containing each analyte at
1000 times selected concentration. With a syringe, add 50 nl
of the concentrate to each of four to seven 50-mL aliquots of
reagent water, and analyze each aliquot according to
procedures beginning in Sect. 11.
9.3.2 For each analyte the recovery value for all of these samples
must fall in the range of ± 20% of the fortified amount, and
the RSD of the measurements must be 20% or less. For those
compounds that meet the acceptance criteria, performance is
judged acceptable and sample analysis may begin. For those
compounds that fail these criteria, this procedure must be
531.1-10
-------
repeated using four samples until satisfactory performance
has been demonstrated.
9.3.3 To determine the MDL, analyze a minimum of 7 LFBs prepared at
• a low concentration. Use the concentrations in Table 3 as a
guide, or use calibration data to estimate a concentration
that will yield a peak with a signal to noise ratio of
approximately 5. Analyze the 7 replicates as described in
Sect. 11, and on a schedule that results in the analyses being
conducted over several days. Calculate the mean accuracy and
standard deviation for each analyte. Calculate the MDL using
the equation given in Table 3.
9.3.4 The initial demonstration of capability is used primarily to
preclude a laboratory from analyzing unknown samples via a
new, unfamiliar method prior to obtaining some experience
with it. It is expected that as laboratory personnel gain
experience with this method the quality of data will improve
beyond those required here.
9.4 The a/?a,7yst is permitted to modify HPLC columns, HPLC conditions,
and internal standards to improve separations or lower analytical
costs. Each time such method modifications are made, the analyst
mustirepeat the procedures in Sect. 9.3.
9.5 ASSESSING THE INTERNAL STANDARD
9.5.1
When using the internal standard calibration procedure, the
analyst must monitor the IS response (peak area or peak.
height) of all samples during each analysis day. The IS
response for any sample chromatogram should not deviate from
the daily calibration check standard's IS response by more
30%.
9.5.2-If >30% deviation occurs with an individual extract, optimize
[instrument performance and inject a second aliquot.
•9.5.2.1 If the reinjected aliquot produces an acceptable
internal standard response, report results for that
aliquot.
K5.2.2
If a deviation of greater than 30% is obtained for
the reinjected extract, analysis of the sample
, should be repeated beginning with Sect. 11, provided
*' a duplicate sample is still available. Otherwise,
• report results obtained from the reinjected extract,
V% but annotate as suspect.
9.5.3 If consecutive samples fail the IS response acceptance
chterion, immediately analyze a calibration check standard.
531.1-11
-------
9.5.3.1 If the check standard provides a response for the IS
within 20% of the predicted value, then follow
procedures itemized in Sect. 9.5.2 for each sample
failing the IS response criterion.
9.5.3.2 If the check standard provides a response for the IS
which deviates more than 20% of the predicted value,
then the analyst must recalibrate, as specified in
Sect. 10. •
9.6 ASSESSING LABORATORY PERFORMANCE - LABORATORY FORTIFIED BLANKS
9.6.1 The laboratory must analyze at least one laboratory fortified
blank (LFB) sample with every 20 samples or one per sample
set (all samples analyzed within a 24-h period) whichever is
greater. The fortification concentration of each analyte in
the LFB should be 10 times EI3L or a concentration in the
middle of the calibration range. Calculate accuracy as
percent recovery (X{). If the recovery of any analyte falls
outside the control limits (see Sect. 9.6.2), that analyte is
judged out'of control, and the source of the problem must be
identified and resolved before continuing analyses.
9.6.2 Until sufficient data become available from within their own
laboratory, usually a minimum of results from 20 to 30
analyses, the laboratory should assess laboratory performance
against the control limits in Sect. 9.3.2. When sufficient
internal performance data becomes available, develop control
limits from the mean percent recovery (X) and standard
deviation (S) of the percent;recovery, these data are used
to establish upper and lower control limits as follows:
UPPER CONTROL LIMIT = X + 3S
LOWER CONTROL LIMIT = X - 3S
After each five to ten new recovery measurements, new control
limits should be calculated using only the most recent 20-30
data points. These calculated control limits should not
exceed those established in Sect. 9:3.2.
9.6.3 If acceptable accuracy and method detection limits cannot be
achieved, the problem must be located and corrected before
further samples are analyzed, Data from all field samples
analyzed since the last acceptable LFB should be considered
suspect, and duplicate samples should be analyzed, if they
are available, after the problem has been corrected. LFB
results should be added to the on-going control charts to
document data quality.
Since the calibration check sample in Sect. 10.2.4 and 10.3.3
and the LFB are made the same way and since procedural
531.1-12
-------
standards are used, the sample analyzed here may also be used
as a calibration check as described in those sections.
9.6.4 It is recommended that the laboratory periodically determine
and document its detection limit capabilities for analytes of
interest.
9.6.5 At least quarterly, analyze a QC sample from an outside
source.
9.7 ASSESSING ANALYTE RECOVERY - LABORATORY FORTIFIED SAMPLE MATRIX
9.7.1 The laboratory must add a known concentration to a minimum of
5% of the routine samples or one sample per set, whichever is
greater. The concentration should not be less then the
background concentration of the sample selected for
fortification. Ideally, the concentration should be the same
as that used for the laboratory fortified blank (Sect. 9.6).
Over time, samples from all routine sample sources should be
fortified.
9.7.2 Calculate the percent recovery, P, of the concentration for
each analyte, after correcting the analytical result,1 X, from
the fortified sample for the background concentration, b,
measured in the unfortified sample, i.e.,:
P = 100 (X - b) / fortifying concentration,
and compare these values to control limits appropriate for
reagent water data collected in the same fashion. The value
for P must fall in the range of 65%-135% of the fortified
amount.
9.7.3 If the recovery of any such analyte falls outside the
designated range, and the laboratory performance for that
analyte is shown to be in control (Sect. 9.6), the recovery
problem encountered with the dosed sample is judged to be
matrix related, not system related. The result for that
analyte in the unfortified sample is labeled suspect/matrix
to inform the data user that the results are suspect due to
matrix effects.
9.8 ASSESSING INSTRUMENT SYSTEM - LABORATORY PERFORMANCE CHECK SAMPLE -
Instrument performance should be monitored on a daily basis by
analysis of the LPC sample. The LPC sample contains compounds
designed to monitor instrument sensitivity, column performance
(primary column) and chromatographic performance. LPC sample
components and performance criteria are listed in Table 4.
Inability to demonstrate acceptable instrument performance indicates
the need for revaluation of the instrument system. The sensitivity
requirements are set based on the EDLs published in this method. If
laboratory EDLs differ from those listed in this method,
531.1-.13
-------
concentrations of the LPC standard compounds must be adjusted to be
compatible with the laboratory ED|_s.
9.9 The laboratory may adopt additional quality control practices for
use with this method. The specific practices-that are most
productive depend upon the needs of the laboratory and the nature of
the samples. For example, field or laboratory duplicates may be
analyzed to assess the precision of the environmental measurements
or field reagent blanks may be used to assess contamination of
samples under site conditions, transportation and storage.
10. CALIBRATION AND STANDARDIZATION ;
10.1 Establish HPLC operating parameters equivalent to those indicated in
Sect. 6.6. The HPLC system may be calibrated using either the
internal standard technique (Sect. 10.2) or the external standard
technique (Sect. 10.3).
10.2 INTERNAL STANDARD CALIBRATION PROCEDURE. The analyst must select
one or more internal standards similar in analytical behavior to the
analytes of interest. The analyst must further demonstrate that the
measurement of the internal standard is not affected by method or
matrix interferences. BDMC has been identified as a suitable
internal standard.
10.2.1 Prepare calibration standards at a minimum of three
(recommend five) concentration levels for each analyte of
interest by adding volumes of one or more of the stock
standards to a volumetric flask. Guidance on the number of
standards is as follows: A minimum of three calibration
standards are required to calibrate a range of a factor of 20
in concentration. For a factor of 50 use at least four
standards, and for a factor of 100 at least five standards.
The lowest standard should represent analyte concentrations
near, but above, their respective MDLs. The remaining
standards should bracket the analyte concentrations expected
in the sample, or should define the working range of the
detector. To each calibration standard, add a known constant
amount of one or more internal standards, and dilute to
volume with buffered reagent water. To prepare buffered
reagent water, add 10 mL of 1.0 M monochlo.roacetic acid
buffer to 1 L of reagent water.
10.2.2 Analyze each calibration standard according to the procedure
in Sect. 11. Tabulate peak height or area responses against
concentration for each compound and internal standard.
Calculate response factors (RF) for each analyte and
surrogate using Equation 1.
RF =
(A,)(CU)
Equation 1
531.1-14
-------
where:
As = Response for the analyte to be measured
Ais = Response for the internal standard.
Cjs = Concentration of the internal standard /ig/L).
Cs = Concentration of the analyte to be measured
10.2.3 If the RF value over the working range is constant (20% RSD
or less), the average RF can be used for calculations
Alternatively, the results can be used to plot a calibration
curve of response ratios (As/Ais) vs. Cs.
10.2.4 The working RF or calibration curve must be verified on each
working day by the measurement of a minimum of two
calibration check standards, one at the beginning and one at
the end of the analysis day. These check standards should be
at two different concentration levels to verify the
concentration curve. For extended periods of analysis
(greater than 8 hr), it is strongly recommended that check
standards be interspersed with samples at regular intervals
during the course of the analyses. If the response for any
analyte varies from the predicted response by more than ±20%
the test must be repeated using a fresh calibration standard'
.If the results still do not agree, generate a new calibration
curve.
10.3 EXTERNAL STANDARD CALIBRATION. PROCEDURE
10.3.1 Prepare calibration standards as described in Sect 10.2 1
omitting the use of an internal standard.
10.3.2 Starting with the standard of lowest concentration, analyze
each calibration standard according to Sect. 11.2 and
tabulate responses (peak height or area) versus the
concentration in the standard. The results can be used to
prepare a calibration curve for each compound
Alternatively, if the ratio of response to concentration
(calibration factor) is a constant over the working range
(<20% relative standard deviation), linearity through the
origin can be assumed and the average ratio or calibration
factor can be used in place of a calibration curve.
10.3.3 The working calibration curve or calibration factor must be
verified on each working day as described in Sect. 10.2.4.
10.4 Verify calibration standards periodically, recommend at least
quarterly by analyzing a standard prepared from reference material
obtained from an independent source. Results from these analyses
must be within the limits used to routinely check calibration (Sect
531.1-15
-------
11. PROCEDURE
11.1 PH ADJUSTMENT AND FILTRATION :
11.1.1 Add preservative to any samples (LFBs, LRBs, or calibration
standards) not previously preserved (Sect. 8). Adjust the pH
of the sample or standard to pH 3 ± 0.2 by adding 1.5 ml of
2.5 M monochloroacetic acid buffer to each 50 ml of sample.
This step should not be necessary if sample pH was adjusted
during sample collection as a preservation precaution. Fill
a 50-mL volumetric flask to the mark with the sample. Add 5
jiL of the internal standard fortification solution (if the
internal standard calibration procedure is being employed)
and mix by inverting the flalsk several times.
11.1.2 Affix the three-way valve to a 10-mL syringe. Place a clean
filter in the filter holder and affix the filter holder and
the 7- to 10-cm syringe needle to the syringe valve. Rinse
the needle and syringe with reagent water. Prewet the filter
by passing 5 ml of reagent water through the filter. Empty
the syringe and check for leaks. Draw 10 mL of sample into
the syringe and expel through the filter. Draw another 10 mL
of sample into the syringe, expel through the filter, and
collect the last 5 mL for analysis. Rinse the syringe with
reagent water. Discard the filter. •
11.2 LIQUID CHROMATOGRAPHY
11.2.1 Sect. 6.6 summarizes the recommended operating conditions for
the liquid chromatograph. Table 1 lists retention times
observed using this method. Other HPLC columns or chromato-
graphic conditions may be used if the requirements of Sect. 9
are met'. ;
11.2.2 Calibrate or verify the system calibration daily as described
in Sect. 10. The standards and samples must be in pH 3
buffered water. •
11.2.3 Inject 400 /iL of the sample. Record the volume injected and
the resulting peak size in area units.
11.2.4 If the response for the peak exceeds the working range of the
system, dilute the sample with pH 3 buffered reagent water
and reanalyze.
11.3 IDENTIFICATION OF ANALYTES
11.3.1 Identify a sample component by comparison of its retention
time to the retention time of a reference chromatogram. If
the retention time of an unknown compound corresponds, within
limits, to the retention time of a standard compound, then
identification is considered positive.
531.1-16 ;
-------
11.3.2 The width of the retention time window used to make
identifications should be based upon measurements of actual
retention time variations of standards over the course of a
day. Three times the standard deviation of a retention time
can be used to calculate a suggested window size for a
compound. However, the experience of the analyst should
weigh heavily in the interpretation of chromatograms.
11.3.3 Identification requires expert judgement when sample
components are not resolved chromatographically. When peaks
obviously represent more than one sample component (i.e.,
broadened peak with shoulder(s) or valley between two or more
maxima), or any time doubt exists over the identification of
a peak on a chromatogram, appropriate alternate techniques,
to help confirm peak identification, need to be employed.
. For example, more positive identification may be made by the
use of an alternative detector which operates on a
chemical/physical principle different from that originally
used; e.g., mass spectrometry (1), or the use of a second
chromatography column. A suggested alternative column is
described in Sect. 6.6.3.
12. CALCULATIONS
Determine the concentration of individual compounds in the sample using
the following equation:
Cx = (AJ (QJ
(As) (RF>
where: Cx = analyte" concentration in micrograms per liter;
Ax = response of the sample analyte;
As = response of the standard (either internal or
external), in units consistent with those used
for the analyte response;
RF = response factor (with an external standard, RF = 1,
because the standard is the same compound as the
measured analyte; with an internal standard RF is a
unitless value);
Qs = concentration of internal standard present or
concentration of external standard that produced As,
in micrograms per liter.
Use the multi-point calibration established in Section 10 for all
calculations. Do not use the daily calibration verification data to
quantitate analytes-in samples.
531.1-17
-------
13. METHOD PERFORMANCE
13.1 In a single laboratory, analyte recoveries from reagent water were
used to determine analyte MDLs and EDLs and demonstrate method
range. Analyte recoveries and standard deviation about the percent
recoveries at one concentration are given in Table 3.
13.2 In a single laboratory, analyte recoveries from two standard
synthetic ground waters were determined at one concentration level.
Results were used to demonstrate applicability of the method to
different ground water matrices. Analyte recoveries from the two
synthetic matrices are given in Table 2.
14. REFERENCES
3.
4.
5.
6.
7.
Behymer, T.D., Bel
of Benzidines and
Liquid Extraction
Performance Liquid
in Methods for the
lar, T.A., Ho, J.S., Budde, W.L., "Determination
Nitrogen Containing Pesticides in Water by Liquid-
or Liquid-Solid Extraction and Reverse Phase High
Chromatography/Particle Beam/Mass Spectrometry"
Determination of Organic Compounds in Drinking
Water. Supplement
Exposure Research
2 (1992). EPA/600/R-92/129 USEPA, National
Laboratory, Cincinnati,Ohio 45268.
Moye, H.A., S.J. Sherrer, and P. A. St. John, "Dynamic Labeling of
Pesticides for High Performance Liquid Chromatography: Detection of
N-Methylcarbamates and o-Phthalaldehyde," Anal. Lett. 10, 1049,
1977.
ASTM Annual Book of Standards, Part 11, Volume 11.02, D3694-82,
"Standard Practice for Preparation of Sample Containers and for
Preservation," American Society for Testing and Materials, Philadel-
phia, PA, p. 86, 1986.
"Carcinogens - Working with Carcinogens," Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77-206, Aug. 1977.
"OSHA Safety and Health Standards, General Industry," (29 CFR 1910),
Occupational Safety and Health Administration, OSHA 2206, (Revised,
January 1976).
"Safety in Academic Chemistry Laboratories," American Chemical
Society Publication, Committee on Chemical Safety, 3rd Edition,
1979.
Foerst, D. L. and H. A. Moye, "Aldicarb in Drinking Water via Direct
Aqueous Injection HPLC with Post Column Derivatization," Proceedings
of the 12th annual AWWA Water Quality Technology Conference, 1984.
531.1-18
-------
I
M1! iu i i Hollowen, and L. A. DalCortevo, "Determination of
N-Methylcarbamate Pesticides in Well Water by Liquid Chromatography
and Post Column Fluorescence Derivatization," Anal. Chem. 56, 2465
(1984).
ASTM Annual Book of Standards, Part 11, Volume 11.01, D3370-82
"Standard Practice for Sampling Water," American
and Materials, Philadelphia, PA, p. 130, 1986.
Society for Testing
531.1-19
-------
*17. TABLES. DIAGRAMS. FLOWCHARTS. AND VALIDATION DATA
TABLE 1. RETENTION TIMES FOR METHOD ANALYTES
Retention Time(a)
(minutes)
Analvte Primarv(1) A1ternative(2) Alternative'3*
Aldicarb sulfoxide 6.80
Aldicarb sulfone 7.77
Oxamyl 8.20
Methomyl 8.94
3-Hydroxycarbofuran 13.65
Aldicarb 16.35
Baygon 18.86
Carbofuran 19.17
Carbaryl 20.29
Methiocarb 24.74
BDMC 25.28
15.0
15.2
17.4
18.4
23.
27,
29.
.3
,0
.3
29.,6
30.8
34.9
35.5
17.5
12.2
14.6
14.8
19
21.4
24.4
23.4
25.4
28.6
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THIS PAGE LEFT BLANK INTENTIONALLY
531.1-24
-------
METHOD 551.1
DETERMINATION OF CHLORINATION DISINFECTION BYPRODUCTS
CHLORINATED SOLVENTS, AND HALOGENATED PESTICIDES/
HERBICIDES IN DRINKING WATER BY LIQUID-LIQUID
EXTRACTION AND GAS CHROMATOGRAPHY WITH ELECTRON-
CAPTURE DETECTION
Revision 1.0
J.W. Hodgeson, A.L. Cohen - Method 551, (1990)
D.J. Munch (USEPA, Office of Water) and D.P. Hautman (International
Consultants, Inc.) - Method 551.1, (1995)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
551.1-1
-------
METHOD 551.1
DETERMINATION OF CHLORINATION DISINFECTION BYPRODUCTS, CHLORINATED SOLVENTS,
AND HALOGENATED PESTICIDES/HERBICIDES IN DRINKING WATER BY LIQUID-LIQUID
EXTRACTION AND GAS CHROMATOGRAPHY WITH ELECTRON-CAPTURE DETECTION
1. SCOPE AND APPLICATION
1.1 This method (1-9) is applicable to the determination of the
following analytes in finished drinking water, drinking water during
intermediate stages of treatment, and raw source water. The
particular choice of analytes from this list should be a function of
the specific project requirements.
Disinfection Byproducts (DBPs);
Analvte CAS No.
Trihalomethanes Chloroform 67-66-3
Bromodichloromethane 75-27-4
Bromoform 75-25-2
Dibromochloromethane 124-48-1
Haloacetonitriles Bromochloroacetonitrile 83463-62-1
Dibromoacetonitrile 3252-43-5
Dichloroacetonitrile 3018-12-0
Trichloroacetonitrile 545-06-2
Other DBFs Chloral Hydrate 75-87-6
Chloropicrin 76-06-2
l,l-Dichloro-2-propanone 513-88-2
l,l,l-Trichloro-2- 918-00-3
propanone
Chlorinated Solvents:
Carbon Tetrachloride 56-23-5
l,2-Dibromo-3-; 96-12-8
chloropropane [DBCP]
1,2-Dibromoethane [EDB] 106-93-4
Tetrachloroethylene 127-18-4
1,1,1-Trichloroethane 71-55-6
1,1,2-Trichloroethane 79-00-5
Trichloroethylene 79-01-6
1,2,3-Trichloropropane 96-18-4
Pesti ci des/Herbi ci des;
Alachlor 15972-60-8
Atrazine 1912-24-9
Bromacil 314-40-9
Cyanazine 21725-46-2
Endrin 72-20-8
Endrin Aldehyde 7421-93-4
Endrin Ketone 53494-70-5
Heptachlor 76-44-8
Heptachlor Epoxide 1024-57-3
Hexachlorobenzene 118-74-1
551.1-2
-------
Hexachlorocyclopentadiene 77-47-4
Lindane (gamma-BHC) 58-89-9
Metolachlor 51218-45-2
Metribuzin 21087-64-9
Methoxychlor 72-43-5
Trifluralin 1582-09-8
1.2 This analyte list includes twelve commonly observed chlorination-
disinfection byproducts (3,4), eight commonly used chlorinated
organic solvents and sixteen halogenated pesticides and herbicides.
1.3 This method is intended as a stand-alone procedure for either the
analysis of only the trihalomethanes (THMs) or for all the
chlorination disinfection by-products (DBPs) with the chlorinated
organic solvents or as a procedure for the total analyte list. The
dechlorination/preservation technique presented in section 8 details
two different dechlorinating agents. Results for the THMs and the
eight solvents may be obtained from the analysis of samples
employing either dechlorinating agent. (Sect. 8.1.2)
1.4 After an analyte has been identified and quantitated in an unknown
sample with the. primary GC column (Sect. 6.9.2.1) qualitative
confirmation of results is strongly recommended by gas
chromatography/mass spectrometry (GC/MS) (10,11), or by GC analysis
using a dissimilar column (Sect. 6,9.2.2).
1.5 The experimentally determined method detection limits (MDLs) (12)
for the above listed analytes are provided in Tables 2 and 8.
Actual MDL values will vary according to the particular matrix
analyzed and the specific instrumentation employed.
1.6 This method is restricted to use by or under the supervision of
analysts experienced in the use of GC and in the interpretation of
gas chromatograms. Each analyst must demonstrate the ability to
generate acceptable results with this method-using the procedure
described in Sect. 9.4.
1.7 Methyl-t-butyl ether (MTBE) is recommended as the primary extraction
solvent in this method since it effectively extracts all of the
target analytes 1isted in Sect. 1.1. However, due to safety
concerns associated with MTBE and the current use of pentane by some
laboratories for certain method analytes, pentane is offered as an
optional extraction solvent for all analytes except chloral hydrate.
If project requirements specify the analysis of chloral hydrate,
MTBE must be used as the extracting solvent. This method includes
sections specific for pentane as an .optional solvent.
2. SUMMARY OF METHOD
2.1 A 50 ml sample aliquot is extracted with 3 ml of MTBE or 5 mL of
pentane. Two /*L of the extract is then injected into a GC equipped
551.1-3
-------
with a fused silica capillary column and linearized electron capture
detector for separation and analysis. Procedural standard
calibration is used to quantitate;method analytes.
2.2 A typical sample can be extracted and analyzed by this method in 50
min for the chlorination by-products/chlorinated solve'nts and 2 hrs.
for the total analyte list. Confirmation of the eluted compounds
may be obtained using a dissimilar column (6.9.2.2) or by the use of
GC-MS. Simultaneous confirmation,can be performed using dual
primary/confirmation columns installed in a single injection port
(Sect. 6.9.3) or a separate confirmation analysis.
3. DEFINITIONS
3.1 INTERNAL STANDARD (IS) -- A pure analyte(s) added to a sample,
extract, or standard solution in known amount(s) and used to measure
the relative responses of other method analytes and surrogates that
are components of the same sample or solution. The internal
standard must be an analyte that ;is not a sample component.
3.2 SURROGATE ANALYTE (SA) — A pure analyte(s), which is extremely
unlikely to be found in any sample, and which is added directly to a
sample aliquot in known amount(s) before extraction or other
processing and is measured with the same procedures used to measure
other sample components. The purpose of a surrogate analyte is to
monitor method performance with each sample.
3.3 LABORATORY DUPLICATES (LD1 and LD2) — Two sample aliquots, taken in
the laboratory from a single samp'Je bottle, and analyzed separately
with identical procedures. Analyses of LD1 and LD2 indicate
precision associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures. This method
cannot utilize laboratory duplicates since sample extraction must
occur in the sample vial and sample transfer is not possible due to
analyte volatility.
3.4 FIELD DUPLICATES (FD1 and FD2) — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as well as with
laboratory procedures. Since laboratory,duplicates cannot be
analyzed, the collection and analysis of field duplicates for this
method is critical.
3.5 LABORATORY REAGENT BLANK (LRB) —An aliquot of reagent water, or
other blank matrix, that is treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents, internal
standards, and surrogates that are used with other samples. The LRB
is used to determine if method analytes or other interferences are
present in the laboratory environment, the reagents, or the
apparatus.
551.1-4:
-------
3.6 FIELD REAGENT BLANK (FRB) — Reagent water, or other blank matrix,
that is placed in a sample container in the laboratory and treated
as a sample in all respects, including shipment to sampling site,
exposure to sampling site conditions, storage, preservation and all
analytical procedures. The purpose of the FRB is to determine if
method analytes or other interferences are present in the field
environment.
3.7 LABORATORY FORTIFIED BLANK (LFB) — An aliquot of reagent water, or
other blank matrix, to which known quantities of the method analytes
are added in the laboratory. The LFB is analyzed exactly like a
sample, and its, purpose is to determine whether the methodology is
in control, and whether the laboratory is capable of making accurate
and precise analyte quantitation at various concentrations including
the required method detection limit.
3.8 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
3.9 STOCK STANDARD SOLUTION (SSS) — A concentrated solution containing
one or more method analytes which is prepared in the laboratory
using assayed reference materials or purchased as certified from a
reputable commercial source.
3.10 PRIMARY DILUTION STANDARD SOLUTION (PDS) — A solution of several '
analytes prepared in the laboratory from stock standard solutions
and diluted as needed to prepare calibration solutions and other
needed analyte solutions.
3.11 CALIBRATION STANDARD (CAL)— A solution prepared from the primary
dilution standard solution or stock standard solutions and the.
internal standard(s) and surrogate analyte(s). The CAL solutions
are used to calibrate the instrument response with respect to
analyte concentration.
3.12 QUALITY CONTROL SAMPLE (QCS) — A solution of method analytes which
is used to fortify an aliquot of LRB or sample matrix. The QCS is
obtained from a source external to the laboratory and different from
the source of calibration standards. It is used to check laboratory
performance with externally prepared test materials.
3.13 LABORATORY PERFORMANCE CHECK SOLUTION (LPC) -- A solution of
selected method analytes, surrogate(s), internal standard(s), or
other test substances used to evaluate the performance of the
instrument system with respect to a defined set of method criteria.
551.1-5
-------
3.14 METHOD DETECTION LIMIT (MDL) — The minimum concentration of an
analyte that can be identified, measured and reported with 99%
confidence that the analyte concentration is greater than zero.
(Appendix B to 40 CFR Part 136)
3.15 ESTIMATED DETECTION LIMIT (EDL) — Defined as either the MDL or a
level of compound in a sample yielding a peak in the final extract
with a signal to noise (S/N) ratio of approximately 5, whichever is
greater.
3.16 PROCEDURAL STANDARD CALIBRATION — A calibration method where
aqueous calibration standards are prepared and processed (e.g.
purged,extracted, and/or deri'vatized) in exactly the same manner as
a sample.. All steps in the process from addition of sampling
preservatives through instrumental, analyses are included in the
calibration. Using procedural standard calibration compensates for
any inefficiencies in the processing procedure.
4. INTERFERENCES
4.1 Impurities contained in the extracting solvent usually account for
the majority of the analytical problems. Each new bottle of solvent
should be analyzed for interferences before use,. An interference
free solvent is a solvent containing no peaks yielding data at > MDL
(Tables 2 and 8) at the retention times of the analytes of interest.
Indirect daily checks on the extracting solvent are obtained by
monitoring the laboratory reagent blanks (Sect. 9.3). Whenever an
interference is noted in the reagent blank, the analyst should
analyze the solvent separately to determine if the source of the
problem is the solvent or another reagent.
4.2 Glassware must be scrupulously cleaned (13). Clean all glassware as
soon as possible after use by thoroughly rinsing with the last
solvent used in it. Follow by washing with hot water and detergent
and thoroughly rinsing with tap and reagent water. Drain dry, and
heat in an oven or muffle furnace at 400°C for 1 hr. Do not muffle
volumetric ware but instead rinse three times with .HPLC grade or
better acetone. Thoroughly rinsing all glassware with HPLC grade or
better acetone may be substituted for heating provided method blank
analysis confirms no background interferant contamination is
present. After drying and cooling, seal and store all glassware in
a clean environment free of all potential contamination. To prevent
any accumulation of dust or other contaminants, store glassware
inverted on clean aluminum foil or capped with aluminum foil.
4.3 Commercial lots of the extraction solvents (both MTBE and pentane)
often contain observable amounts of chlorinated solvent impurities,
e.g., chloroform, trichloroethylene, carbon tetrachloride. When
present, these impurities can normally be removed by double
distillation.
551.1-6
-------
4.4
This liquid/liquid extraction technique efficiently extracts a
3 of non-polar and polar organic components of the
;. rnnfirmat.inn i <: miifp imnnvtant navMrnl avO w =
wide
4.5
4.6
This liquid/liquid extraction technique efficiently extracts a w
boiling range of non-polar and polar organic components of the
sample. Thus, confirmation is quite important, particularly at
lower analyte concentrations. A confirmatory column (6.9.2.2) is
suggested for this purpose. Alternatively, GC/MS may also be used
for confirmation if sufficient concentration of analyte is present.
Special care must be taken in the determination of endrin since it
has been reported to breakdown to aldo and keto derivatives upon
reaction with active sites in the injection port sleeve (14). The
active sites are.usually the result of micro fragments of the
injector port septa and high boiling sample residual deposited in
the injection port sleeve or on the inner wall at the front of the
capillary column. The degradation of endrin is monitored using the
Laboratory Performance Check Standard (Sect. 9.2).
Interfering and erratic peaks have been observed in method blanks
within the retention windows of metribuzin, alachlor, cyanazine and
heptachlor. These are believed to be due to phthalate
contamination. This contamination can be reduced by paying special
attention to reagent preparation (See solvent rinsing the dry buffer
and the dechlorination/ preservative salts, Sect. 7.1.7.5) and
elimination of all forms of plastic from the procedure (i.e. HOPE
bottles, plastic weighing boats, etc.). After NaCl or Na2S04 is
muffled or phosphate buffer and dechlorination/preservative salts
are solvent rinsed, they should be stored in sealed glass
containers. NaCl, Na2S04, phosphate buffer and dechlorination/
preservative salts should be weighed using glass beakers, never
plastic weighing boats.
5. SAFETY
5.1 The toxicity and carcinogenicity of chemicals used in this method
have not been precisely defined; each chemical should be treated as
a potential health hazard, and exposure to these chemicals should be
minimized. Each laboratory is responsible for maintaining awareness
of OSHA regulations regarding safe handling of chemicals 'used in
this method. Additional references to laboratory safety are
available (15-17) for the information of the analyst.
5.2 The following have been tentatively classified as known or suspected
human or mammalian carcinogens:
Chloroform, l,2-Dibromo-3-chloropropane, 1,2-Dibromoethane,
heptachlor, and hexachlorobenzene.
5.3 The toxicity of the extraction solvent, MTBE, has not been well
defined. Susceptible individuals may experience adverse affects
upon skin contact or inhalation of vapors. Therefore, protective
clothing and gloves should be used and MTBE should be used only in a
chemical fume hood or glove box. The same precaution applies to
pure standard materials.
551.1-7
-------
6. EQUIPMENT AND SUPPLIES (All specifications in Sections 6 and 7 are
suggested. Catalogue numbers are included for illustration only.)
6.1 SAMPLE CONTAINERS - 60-mL screw cap glass vials (Kimble #60958A-16,
Fisher #03-339-5E or equivalent) each equipped with size 24-400 cap
and PTFE-faced septa (Kimble #738,02-24400, Fisher #03-340-14A or
equivalent)r Prior to use or following each use, wash vials and
septa with detergent and tap water then rinse thoroughly with
distilled water. Allow the vials: and septa to dry at room
temperature, place only the vials in an oven and heat to 400°C for
30 min. After removal from the oven allow the vials to cool in an
area known to be free of organics. After rinsing caps with
distilled water, rinse in a beaker with HPLC grade or better acetone
and place in a drying oven at 80°C for 1 hr.
6.2 VIALS - Autosampler, 2.0-mL vial with screw or crimp cap and a
teflon faced septa. :
6.3 MICRO SYRINGES - 10 pi, 25 pi, 50 pi, 100 pi, 250 pi, and 1000 fjl.
6.4 PIPETTES - 3.0 mL or 5.0 mL, type A, TD, glass.
6.5 VOLUMETRIC FLASK - 10 mL, 100 mL, 250 mL, 500 mL glass stoppered.
6.6 DISPOSABLE PASTEUR PIPETS - 9 inch, used,for extract transfer.
6.7 STANDARD SOLUTION STORAGE CONTAINERS - 30-mL Boston round, amber
glass bottles with TFE-lined caps or equivalent.
6.8 BALANCE - Analytical, capable of accurately weighing to the nearest
0.0001 g. :
6.9 GAS CHROMATOGRAPHY SYSTEM ' , -
6.9.1 The GC must be capable of temperature programming and should
be equipped with a linearized electron capture detector
(ECD), fused silica capillary column, and on-column or
splitless injector (splitless mode, 30 sec. delay). If
•simultaneous confirmation is employed the GC must have a
second ECD. An auto-sampler/injector is desirable.
6.9.1.1 SPECIAL PRECAUTION: During method development, a
problem was encountered with the syringe on the
autosampler. The syringe plunger, after repeated
sample extract injections, developed resistance when
withdrawn or inserted into the syringe barrel. This
resistance was dufe to salt deposits in the syringe
barrel which were left behind following the
evaporation of hydrated MTBE. To minimize this
problem, a unique' syringe wash procedure was
employed. After sample injection, the syringe was
first rinsed three times with reagent water then
551.1-81
-------
three times with MTBE. This effectively removed all
the residual salt after each injection from the
syringe and surmounted the problem. Some
autosampler designs may not encounter this problem
but this precaution has been mentioned to alert the
analyst. When pentane was used as the extraction
solvent, this was not a problem.
6.9.2 Two GC columns are recommended. Column A is recommended as
the primary analytical column unless routinely occurring
analytes are not adequately resolved. Column B is
recommended for use as a confirmatory column when GC/MS
confirmation is not sensitive enough or unavailable. Other
GC columns or conditions may be employed provided adequate
analyte resolution is attained and all the quality assurance
criteria established in Sect. 9 are met.
6.9.2.1 Column A - 0.25 mm ID x 30 m fused silica capillary
with chemically bonded methyl polysiloxane phase
(J&W, DB-1,-1.0 m film thickness or equivalent). As
a result of the different boiling points of MTBE
(b.p. 55°C) and pentane (b.p. 35°C), two different
GC oven temperature programs are specified in Table
1 for MTBE and Table 12 for pentane. Retention
times for target analytes were slightly different
using the pentane oven temperature program but
elution order, analyte resolution, and total
analysis time were not effected. Injector
temperature: 200°C equipped with 4 mm ID
deactivated sleeve with wool plug (Restek #20781 for
HP GC's or equivalent). This sleeve design was.
found to give better analyte response than the
standard 2 mm sleeve. Detector temperature: 290°C.
6.9.2.2 Column B - 0.25 mm ID x 30 m with chemically bonded
6 % cyanopropylphenyl/94 % dimethyl polysiloxane
phase (Restek, Rtx-1301, 1.0 /im film thickness or
equivalent). The column oven was temperature
programmed exactly as indicated for column A (Tables
1 and 12). Injector and detector temperatures at
200°C and 290°C, respectively. The same
temperature program was utilized to allow for
simultaneous confirmation analysis.
6.9.3 To perform simultaneous confirmation from a single injection
onto both the primary and confirmation columns, two injector
setups can be employed.
6.9.3.1 Using a two hole graphite ferrule (Restek #20235, or
equivalent) both columns can be inserted into one
injection port. To ensure the column ends are
centered in the injection port sleeve and not angled
551.1-9
-------
to the side,
at the base
equivalent).
this manner
the base of
twisting as
minimize thi
twisted four
seated.
an inlet adaptor fitting is installed
of the injection port (Restek #20633, or
Use caution when installing columns in
to ensure the column does not break at
the injector due to the two columns
the ferrule nut is tightened. To
s hazard, the ferrule nut can be reverse
to five times once the ferrule has been
6.9.3.2 An alternate procedure involves installing a 1 meter
portion of 0.25 mm deactivated, uncoated fused
silica capillary tubing (Restek #10043, or
equivalent) into the injector as a normal single
column is installed. Then using a Y-press tight
union (Restek #20403 or equivalent) join the 1 meter
uncoated column to the primary and secondary
columns. Using this procedure will reduce detection
limits when compared to the procedure outline in
6.9.3.1 since only one column is positioned in the .
injection port to receive the injected sample
extract.
6.9.4 The analyst is permitted to modify GC columns, GC conditions,
internal standard or surrogate compounds. Each time such
method modifications are made, the analyst must repeat the
procedures in Sect. 9.4. '•
7. REAGENTS AND STANDARDS
7.1 REAGENTS
7.1.1 MTBE - High purity grade. It may be necessary to double
distill the solvent if impurities are observed which coelute
with some of the more volatile compounds.
7.1.2 Pentane (optional extraction solvent) - High purity grade. It
may be necessary to double distill the solvent if impurities
are observed which coelute with some of the more volatile
compounds.
7.1.3 Acetone - High purity, demonstrated to be free of analytes.
7.1.4 Methanol - High purity, demonstrated to be free of analytes.
7.1.5 Sodium Chloride, NaCl - ACS Reagent Grade. Before using a
batch of NaCl, place in muffle furnace, increase temperature
to 400°C and hold for 30 rtrin. Store in a capped glass
bottle, not in a plastic container.
7.1.6 Sodium Sulfate, Na2S04 - ACS Reagent Grade. Before using a
batch of Na2S04, place in muffle furnace, increase
551.1-10
-------
temperature to 400°C and hold for 30 min. Store in a capped
glass bottle not in a plastic container.
7.1.7 Sample Preservation Reagents
7.1.7.1 Phosphate buffer - Used to lower the sample matrix
pH to 5.2 in order to inhibit base catalyzed
degradation of the haloacetonitriles (7), some of
tfye chlorinated solvents, and to standardize the pH
of all samples. Prepare a dry homogeneous mixture
of 2.50% Sodium Phosphate, dibasic (Na2HP04)/97.5%
Potassium Phosphate, monobasic (KH2P04) by weight
(example: 5.00 g Na2HPO, and 195 g KH2PO, to yield a
total weight of 200 g) Both of these buffer salts
should be in granular form and of ACS grade or
better. Powder would be ideal but would require
extended cleanup time as outlined below in Sect.
7.1.7.5 to allow for buffer/solvent settling.
7.1.7.2 Ammonium Chloride, NH^Cl, ACS Reagent Grade. Used
to convert free chlorine to monochloramine.
Although this is not the traditional dechlorination
mechanism, ammonium chloride is categorized as a
dechlorinating agent in this method.
7.1.7.3 Sodium Salfite, Na2S03, ACS Reagent Grade. Used as
a dechlorinating agent for chloral hydrate sample
analysis.
7.1.7.4 To simplify the addition of 6.0 mg of the
dechlorinating agent to the 60 mL vial, the
dechlorinating salt is combined with the phosphate
buffer as a homogeneous mixture. Two g of the
appropriate dechlorinating agent are added to 200 g
of the phosphate buffer. When 0.60 g of the
buffer/dechlorinating agent mixture are added to the
60-mL sample vial, 6 mg of the dechlorinating agent
are included reflecting an actual concentration of
100 mg/L. Two separate mixtures are prepared, one
containing ammonium chloride and the other with
sodium sulfite.
7.1.7.5 If background contaminants are detected in the salts
listed in Sections 7.1.7.1 through 7.1.7.3, a
solvent rinse cleanup procedure may be required.
These contaminants may coelute with some of the high
molecular weight herbicides and pesticides. These
salts cannot be muffled since they decompose when
heated to 400°C. This solvent rinsing procedure is
applied to the homogeneous mixture prepared in Sect.
7.1.7.4.
551.1-11
-------
7.2
7.3
NOTE: If a laboratory is not conducting analyses
for the-high molecular weight herbicides and
pesticides, this;cleanup may not be required if no
interfering peaks are observed within the retention
time window (Sect.12.2) for any target analytes in
the laboratory reagent blank.
SOLVENT RINSE CLEANUP PROCEDURE
Prepare two separate homogeneous mixtures of the
phosphate buffer ^alts (Sect. 7.1.7.1) in a 500-mL
beaker. To one, add the correct amount of ammonium
chloride and to the other add the correct amount of
sodium sulfite. Three separate solvents are then
used to rinse the mixture. (This solvent rinsing
must be performed in a fume hood or glove box.)
First, add approx. 100 mL of methanol, or enough to
cover the salt to a depth of approx. 1 cm, and using
a clean spatula, stir the solvent salt mixture for 1
minute. Allow the buffer/solvent mixture to settle
for 1 minute and then decant the methanol, being
careful not to pour off the rinsed buffer. It may
be necessary to perform this procedure up to four
times with methane!. NOTE: By softly lifting and
tapping the base of the beaker against the fume hood
counter surface, more of the solvent is brought to
the surface of the buffer. Next, perform the
identical procedure up to two times using acetone.
Finally, perform two final rinses with the
appropriate extracting solvent (MTBE or Pentane).
After the final solvent rinse, place the "wet"
buffer on a hot plate at approx. 60°C for 30 minutes
or until dry. Stir the mixture every 5 minutes to
aid the evaporation of excess solvent. Once dry,
place the buffer in a glass bottle with either a
ground glass stopper or TFE faced septum.
REAGENT WATER - Reagent water is defined as purified water which
does not contain any measurable quantities of any target analytes or
any other interfering species.
7.2.1 A Millipore Super-Q water system or its equivalent may be
used to generate deionized reagent water. Distilled water
that has been charcoal filtered may also be su.itable.
7.2.2 Test reagent water each day it is used by analyzing according
to Sect. 11.
STOCK STANDARD SOLUTIONS (SSS)- These solutions may be obtained as
certified solutions or prepared from neat materials using the
following procedures:
551.1-12
-------
7.3.1 For analytes which are solids in their pure form, prepare
,stock standard solutions (1 mg/mL) by accurately weighing
approximately 0.01 g of pure material in a 10-mL volumetric
flask. Dilute to volume with acetone. Due to the low
solubility of simazine, this stock should be prepared at 0.5
mg/mL by weighing 0.005 g diluted to volume with acetone in a
10-mL volumetric flask. Alternatively, simazine stock
standard solutions may be prepared in ethyl acetate at
approximately 0.01 g/10 ml. Stock standard solutions for
analytes which are liquid in their pure form at room
temperature can be accurately prepared in the following
manner.
7.3.1.1 Place about 9.8 mL of acetone into a 10-mL ground-
glass stoppered volumetric flask. Allow the flask
to stand, unstoppered, for about 10 min to allow
solvent film to evaporate from the inner walls of
the volumetric flask, and weigh to the nearest 0.1
mg.
1 7.3.1.2 Use a 10-/iL syringe and immediately add 10.0//L of
standard material to the flask by keeping the
syringe needle just above the surface of the
acetone. Caution should be observed to be sure that
, the standard material falls dropwise directly into
the acetone without contacting the inner wall of the
volumetric flask.
7.3.1.3 Reweigh, dilute to volume, stopper, then mix by
inverting the flask several times. Calculate the
concentration in milligrams per milliliter from the
net gain in weight. Final concentration should be
between 0.800 - 1.50 mg/mL.
7.3.2 Larger volumes of standard solution may be prepared at the
discretion of the analyst. When compound purity is assayed
to be 96% or greater, the weight can be used without
correction to calculate the concentration of the stock
standard. -
7.3.3 Commercially prepared stock standards can be used at any
concentration if they are certified by the manufacturer or by
an independent source. When purchasing commercially prepared
stock standards, every effort should be made to avoid
solutions prepared in methanol (chloral hydrate is an
exception, Sect. 7.3.3.1). Methanol can cause degradation of
most of the haloacetonitriles. In addition, some commercial
suppliers have reported instability with solutions of
simazine and atrazine prepared in methanol (18). For these
reasons, acetone should be used as the primary solvent for
stock standard and primary dilution standard preparation and
551.1-13
-------
7.3.4
all sources of methanol introduction into these acetone
solutions should be eliminated.
7.3.3,1 It is extremely difficult to acquire chloral hydrate
in its pure form since it is classified as a
controlled substance. Consequently, if pure chloral
hydrate cannot be acquired, a commercially prepared
solution of this analyte (most often at 1.0 mg/mL)
must be purchased. Most manufactures provide
certified chloral hydrate solutions in methanol.
Since chloral hydrate is unstable, standards from a
separate vendor musft be utilized to confirm the
accuracy of the primary supplier's solution.
Outside source stock solutions, which are independently
prepared or purchased from ah outside source different from
the source for the original stock standard solutions, must be
used as a means of verifying the accuracy of the original
stock standard solutions for all analytes. Prepare a
dilution of both stocks in acetone and perform a final
dilution in MTBE such that each stock dilution is at the same
concentration. Analyze as outlined in Section 11.3. The
relative percent difference (RPD as defined below) between
the analytes' response (area counts) from both solutions
should not exceed 25% for any one analyte. The RPD must be
less than 20% for 90% or greater of the total number of
target analytes analyzed.
RPD =
(DUP 1 - DUP, 2)
((DUP 1 + DUP 2) / 2)
X 100
7.3.4.1
If this criteria cannot be met, a third outside
source should be purchased and tested in the same
manner. When two sources of stock solutions agree,
the accuracy of the stock solutions is confirmed.
This should be done prior to preparing the primary
dilution standards.
7.3.5 Stock Solution of Surrogate - Prepare a stock solution of the
surrogate standard in acetone by weighing approx. 0.010 g
decafluorobiphenyl in a 10-ml. volumetric flask. When diluted
to volume this yields a concentration of 1.00 mg/mL. «
Alternate surrogate analytes,may be selected provided they
are similar in analytical behavior to the compounds of
interest, are highly unlikely to be found in any sample, and
do not coelute with target analytes.
7.3.6 Stock Solution of Internal Standard (IS) - Use of an IS is
optional when MTBE is the extraction solvent but mandatory if
pentane is used. This is due to the high volatility of
pentane when compared to MTBE (see boiling points, Sect.
551.1-14
-------
6.9.2.1). Prepare an internal standard stock solution of
bromofluorobenzene (BFB) in acetone. Since this compound is
a liquid at room temperature, the procedure outlined in
Sections 7.3.1.1 through 7.3.1.3 should be followed but add
approximately 65 //L of neat BFB rather than 10 fji as
specified in 7.3.1.2. When diluted to volume this yields a
concentration near 10.0 mg/mL. Alternate internal standard
analytes may be selected provided they are highly unlikely to
be found in any sample and do not coelute with target
analytes.
7.3.7 Transfer the stock standard solutions into Teflon-lined screw
cap amber bottles. Store at 4°C or less and protect from
light. Stock standard solutions should be checked frequently
for signs of degradation or evaporation, especially just
prior to preparing calibration standards from them.
7.3.8 When stored in a freezer at < -10°C, the THM stock standards
have been shown to be stable for up to six months. The other
analyte stock standards, with the exception of chloral
hydrate, have been shown to be stable for at least four
months when stored in a freezer (<-10°C). Chloral hydrate
stock standards, when stored in a freezer (<-10°C), have been
shown to be stable for two months, however, since freezers
can hold at various temperatures below -10°C, fresh chloral
hydrate standards should be initially prepared weekly, until
the stability of this analyte is determined for a specific
laboratory setting.
7.4 PRIMARY DILUTION STANDARDS (PDS) - Two separate groups of primary
dilution standards must be prepared; one set in acetone for all the
method analytes except chloral hydrate and the second set in
methanol for chloral hydrate. Although preparation of separate
chloral hydrate standards may seem laborious, due to the stability
problems encountered with this analyte, making fresh chloral hydrate
primary dilution standards is more efficient. Prepare primary
dilution standards by combining and diluting stock standards in
acetone (methanol for chloral hydrate). The primary dilution
standards should be prepared such that when 25 //L of this primary
dilution standard are added to 50 ml of buffered/dechlorinated
reagent water (Sect 10.1.2), aqueous concentrations will bracket the
working concentration range. Store the primary dilution standard
solutions in vials or bottles, with caps using TFE faced liners, in
a freezer (<-10°C) with minimal headspace and check frequently for
signs of deterioration or evaporation, especially just before
preparing calibration standards. The same comments on storage
stability in Sect. 7.3.8 apply to primary dilution standards.
7.4.1 SURROGATE PRIMARY DILUTION STANDARD - Dilute 500 //L of the
surrogate stock solution to volume with acetone in a 50-mL
volumetric flask. This yields a primary dilution standard at
10.0 //g/mL. Addition of 50 //L of this standard to 50 ml of
551.1-15
-------
aqueous sample yields a final concentration in water of 10.0
//g/L. This solution is fortified into the aqueous sample
prior to extraction of all calibration standards (Sect.
10.1.3), quality control samples (Sect. 9), laboratory
reagent blanks (Sect. 9.3.1) and actual field samples (Sect.
11.1.3) in the extraction set.
7.4.2 INTERNAL STANDARD (IS) PRIMARY DILUTION STANDARD - Prepare a
IS primary dilution standard at 100 /vg/mL by diluting the
appropriate amount of internal standard stock solution (500
fjl if stock is 10.0 mg/ml) to volume with acetone in a 50-mL
volumetric flask. When 10 //L of this solution are added to
1.0 mL of extract, the resultant final concentration is 1.00
/yg/mL. The internal standard is used in order to perform an
internal standard calibration and is added to an analytically
precise volume of the extract following extraction. This
solution is added to all extracts.
7.4.3 Reserve approximately a 10 mL aliquot of the same lot of both
the acetone and methanol used in the preparation of the
primary dilution standards, When validating the accuracy of
the calibration standards (Sect. 7.3.4), fortify a laboratory
reagent blank with 25 fjl of both the acetone and the methanol
which was used to prepare the primary dilution standards.
Analysis of this laboratory reagent blank will confirm no
target analyte contamination in the solvents used to prepare
the primary dilution standards.
7.5 LABORATORY PERFORMANCE CHECK SOLUTION (LPC) - To insure proper
instrument performance, a Laboratory Performance Check Solution is
prepared. This solution is prepared in MTBE for direct injection on
the GC and is used to evaluate the parameters of instrument
sensitivity, chromatographic performance, column performance and
analyte breakdown. These parameters are listed in Table 7 along
with the method analytes utilized to perform this evaluation, their
concentration in MTBE and the acceptance criteria. To prepare this
solution at the concentrations listed in Table 7, a double dilution
of the analyte stock solutions must be made. First prepare a
primary stock dilution mix at 1000 times the concentrations listed
in Table 7, by adding the appropriate volume of each stock solution
to a single 50-mL volumetric flask containing approximately 25 mL of
MTBE. Dilute to volume with MTBE, Then the LPC working solution is
prepared in MTBE by diluting 50 //L of the primary stock dilution mix
in MTBE to 50-mL in a volumetric flask. The best way to accomplish
this is to add approximately 48 mL MTBE to the 50-mL volumetric
flask and add 50 jjl of the primary stock dilution mix, then dilute
to volume with MTBE. Store this solution in a vial or bottle, with
TFE faced cap, in a freezer (<-10°C) with minimal headspace and
check frequently for signs of deterioration or evaporation.
7.5.1 If a laboratory is not conducting analyses for the high
molecular weight pesticides and herbicides, a modified LPC
551.1-16;
-------
may be prepared. This modified LPC can omit the endrin
analyte breakdown component as well as the resolution
requirement for bromacil and alachlor under column
performance. In addition, substitute analytes in place of
nndane for the sensitivity check and
hexachlorocyclopentadiene for chromatographic performance can
be selected. These substitute compounds must meet the same
criteria as listed in table 7 with the concentration for
sensitivity check near the substitute analyte's EDL and the
concentration for chromatographic performance near 50 times
the substitute analyte's EDL. The column performance
criteria for resolution between bromodichloromethane and
trichloroethylene cannot be modified.
7.5.2 If pentane is selected as an alternate extraction solvent the
LPC must also be prepared in pentane.
8. SAMPLE COLLECTION. PRESERVATION. AND STORAGE
8.1 SAMPLE VIAL PREPARATION
8.1.1 To conduct analyses for the total analyte list, two sets of
60-mL vials must be prepared for sampling. One set of vials
prepared for the analysis of all target analytes except
chloral hydrate, contains ammonium chloride as a
dechlorinating agent. Due to concerns over low recoveries
for chloral hydrate in matrices preserved with ammonium
chloride (Sect. 8.1.2), a separate sample set must be
collected and preserved with sodium sulfite. Both sets of
vials are prepared as follows.
8.1.1.1 Using the homogeneous phosphate ;
buffer/dechlorinating agent mixtures prepared in
Sect. 7.1.7.4, 0.60 g of the appropriate mixture are
added to the corresponding vials.
8.1.2 If the sample assay is for only the THMs and/or solvents,
either dechlorinating agent can be added. However, sodium
sulfite promotes the decomposition of the haloacetonitriles,
l,l-dichloro-2-propanone, l,l,l-trichloro-2-propanone and
chloropicrin and therefore ammonium chloride must be used as
the dechlorination reagent in their analysis. In addition,
some fortified matrices, dechlorinated with ammonium
chloride, have displayed recoveries of chloral hydrate which
have been up to 50% lower than expected, when compared to the
same sample matrix dechlorinated with sodium sulfite. In
other matrices, recoveries have been consistent regardless of
dechlorinating agent. The reason for these differences has
not been determined. Due to this uncertainty, a separate
sample, dechlorinated with 100 mg/L sodium sulfite must be
collected for the analysis of chloral hydrate.
551.1-17
-------
8.1.3 The dechlorinating agents, if not added within the
homogeneous mixture of the; buffer, must be added to the
sampling vials as a dry salt. Solutions of the
dechlorinating agents should not be used due to concerns over
the stability of these salts dissolved in solution and the
potential chemical interactions of aqueous solutions of these
salts with the dry phosphate buffer.
8.1.4 Samples must contain either 100 mg/L ammonium chloride or
sodium sulfite, as appropriate for the analysis being
performed. This amount will eliminate free chlorine residual
in typical chlorinated drinking water samples. If high
chlorine doses are used, such as in a maximum formation
potential test, additional dechlorinating reagent may be
required.
8.2 SAMPLE COLLECTION
8.2.1 Collect all samples in duplicate. Fill sample bottles to
just overflowing but ;take care not to flush out the buffer/
dechlorination reagents. No air bubbles should pass through
the sample as the bottle is filled, or be trapped in the
sample when the bottle is sealed.
8.2.2 When sampling from a water tap, open the tap and allow the
system to flush until the water temperature has stabilized
(usually about 3-5 min). Remove the aerator and adjust the
flow so that no air bubbles are visually detected in the
flowing stream.
8.2.3 When sampling from an open body of water, fill a 1-quart
wide-mouth glass bottle or 1-liter beaker with sample from a
representative area, and carefully fill duplicate 60-mL
sample vials from the container.
8.2.4 The samples must be chilled to 4°C on the day of collection
and maintained at that temperature until analysis. Field
samples that will not be received at the laboratory on the
day of collection must be packaged for shipment with
sufficient ice to ensure they will be at 4°C on arrival at
the laboratory. Synthetic ice (i.e. Blue ice) is not
recommended.
8.3 SAMPLE STORAGE/HOLDING TIMES :
8.3.1 Store samples at 4°C and extracts in a freezer (<-10°C) until
analysis. The sample storage area must be free of organic
solvent vapors.
551.1-18
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8.3.2 Extract all samples within 14 days of collection and analyze
within 14 days following extractidn. This applies to either
MTBE or pentane extracts). Samples not analyzed within these
time periods must be discarded and replaced.
9. QUALITY CONTROL
9.1 Each laboratory that uses this method is required to operate a
formal quality control (QC) program. Minimum QC requirements
include the laboratory performance check standard, initial
demonstration of laboratory capability, method detection limit
determination, analysis of laboratory reagent blanks, continuing
calibration check standard, laboratory fortified sample matrices,
field duplicates and monitoring surrogate and/or internal standard
peak response in each sample and blank. Additional quality control
practices may be added.
i
9.2 ASSESSING.INSTRUMENT SYSTEM - LABORATORY PERFORMANCE CHECK STANDARD
(LPC). Prior to any sample analyses, a laboratory performance check
standard must be analyzed. The LPC sample contains compounds
designed to indicate appropriate instrument sensitivity, endrin
breakdown, column performance (primary column), and chromatographic
performance. LPC sample components and performance criteria are
listed in Table 7. Inability to demonstrate acceptable instrument
performance indicates the need for revaluation of the instrument
system. The sensitivity requirement is based on the Estimated
Detection Limits (EDLs).published in this method. If laboratory
EDLs differ from those listed in this method, concentrations of the
LPC standard must be adjusted to be compatible with the laboratory
EDLs. If endrin breakdown exceeds 20 %, the problem can most likely
be solved by performing routine maintenance on the injection port
including replacing the injection port sleeve, and all associated
seals and septa. If column or chromatographic performance criteria
cannot be met, new columns may need to be installed, column flows
corrected, or modifications adapted to the oven temperature program.
During early method development work, significant chromatographic
and column performance problems were observed while using a DB-1
column which had been used for several years for drinking water
extract analysis. By installing a new DB-1 column, these
performance problems were overcome. If the columns to be used for
this method have been used for several years or have had extended
use with extracts from harsh sample matrices (i.e. wastewater,
acidified sample extracts, hazardous waste samples) it may be
difficult to meet the criteria established for this LPC standard and
column replacement may be the best alternative.
9.3 LABORATORY REAGENT BLANKS (LRB). Before processing any samples, the
analyst must analyze an LRB to demonstrate that all glassware and
reagent interferences are under control. In addition, each time a
set of samples is extracted or reagents are changed, a LRB must be
analyzed. If the LRB produces a peak within the retention time
window of any analyte (Sect. 12.2) preventing the quantitation of
551.1-19
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that analyte, determine the source of the contamination and
eliminate the interference before processing samples. LRB samples
must contain the appropriate buffer for the target analytes
(buffered/NH4Cl dechlorinated and/or buffered/Na2S03 dechlorinated
reagent water).
9.3.1 Prepare the two LRBs in the appropriate buffered/
dechlorinated reagent water* Add 50 //L of surrogate primary
dilution standard (Sect. 7.4.1) to each blank and follow the
procedure outlined in Sect. 11.2.
9.4 INITIAL DEMONSTRATION OF CAPABILITY (IDC)
9.4.1 Preparation' of the IDC Laboratory Fortified Blank (LFB).
Select a concentration for each of the target analyte which
is approximately 50 times the EDL or close to the expected
levels observed in field samples. Concentrations near
analyte levels in Table 3.A are recommended. Prepare a LFB
by adding the appropriate concentration of the primary
dilution standard (Sect. 7.4) to each of four to seven 50 mL .
aliquots of buffered/NH4Cl dechlorinated reagent water.
Separate Na,S03 preserved matrices need not be analyzed
(Sect. 9.4.1.1). Analyze the aliquots according to the
method beginning in Section 11.
9.4.1.1 Chloral hydrate is included in the buffered/NH4Cl
dechlorinated reagent water, containing all the
other target analytes since no matrix induced
recovery problems have been found from reagent water
preserved with NH4C1.
9.4.2 Following procedural calibration standard analysis and
subsequent instrument calibration, analyze a set of at least
seven IDC samples and calculate the mean percent recovery (R)
and the relative standard deviation of this recovery (RSD).
The percent recovery is determined as the ratio of the
measured concentration to the actual fortified concentration.
For each analyte, the mean recovery value must fall within
the range of 80% to 120% and the RSD must not exceed 15 %.
For those compounds that meet these criteria, performance is
considered acceptable, and sample analysis may begin. For
those compounds that fail these criteria, this procedure must
be repeated using eight fresh samples until satisfactory
performance has been demonstrated.
9.4.3 The initial demonstration of capability is used primarily to
preclude a laboratory from analyzing and reporting unknown
samples without obtaining some experience with an unfamiliar
method. It is expected that as laboratory personnel gain
experience with this method, the quality of data will improve
beyond those specified in Sect. 9.4.2.
551.1-20 i
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9.4.4 METHOD DETECTION LIMITS (MDL). Prior to the analysis of any
field samples the method detection limits must be determined.
Initially, estimate the concentration of an analyte which
would yield a peak equal to 5 times the baseline noise and
drift. Prepare a primary dilution standard with analyte
concentrations at 1000 times this level in acetone (or
methanol for chloral hydrate).
9.4.4.1 Prepare a 500 mL aliquot of buffered/ammonium
chloride dechlorinated reagent water. Fill a
minimum of seven replicate, 60-mL vials with 50 ml
of the buffered/dechlorinated (NH4C1) reagent water.
9.4.4.2 Fortify the 50 ml buffered/dechlorinated (NH4C1)
reagent water with 50 fjl of both the MDL concentrate
prepared in acetone and the chloral hydrate MDL
concentrate in methanol. •Separate preparation of a
reagent water containing Na2S03 as the
dechlorinating agent for chloral hydrate MDL
determination is not necessary. (See Sect. 9.4.1.1)
9...4.4.3 Extract and analyze these samples as outlined in
Section 11. MDL determination can then be performed
as discussed in Sect. 13.1.
9.5 LABORATORY FORTIFIED BLANK (LFB). Since this method utilizes
procedural calibration standards, which are fortified reagent water,
there is no difference between the LFB and the continuing
calibration check standard. Consequently, there is not a
requirement .for the analysis of an LFB. However, the criteria
established for the continuing calibration check standard (Sect.
10.4) should be evaluated as the LFB.
9.6 LABORATORY FORTIFIED SAMPLE MATRIX (L.FM).. The laboratory must add
known concentrations of analytes to a minimum of 10% of the routine
samples or one fortified sample per sample set, whichever is
greater, for both NH4C1 and Na2S03 dechlorinated sample matrices.
The concentrations should be equal to or greater than the background
concentrations in the sample selected for fortification. Over time,
samples from all routine sample sources should be fortified. By
fortifying sample matrices and calculating analyte recoveries, any
matrix induced analyte bias is evaluated. When an analyte recovery
falls outside the acceptance criteria outlined below, a bias is
concluded and that analyte for that matrix is reported to the data
user as suspect.
9.6.1 First, follow the procedure outlined in Sect. 11.1
9.6.2 Next, prepare thei LFM by adding 50/yL of an acetone based
standard solution into the remaining 50 mL of the buffered/
NH4C1 dechlorinated sample matrix in the vial in which it was
551.1-21
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sampled. This sample vial will have had the required amount
of aqueous sample- removed as specified in Sect. 11.1.2. Add
50 /jl of surrogate primary dilution standard (Sect. 7.4.1)
and follow procedure outlined in Sections 1.1 and 12.
9.6.3 When chloral hydrate is being determined, prepare the LFM by
adding 50 jul of a methanol based chloral hydrate standard
solution into 50 ml_ of the buffered/Na2S03 dechlorinated
sample matrix in the vial in which it was sampled. Add 50 /vL
of surrogate primary dilution standard (Sect. 7.4.1) and
follow procedure outlined in Sections.11 and 12.
9.6.4 Calculate the percent recovery, R, of the concentration for
each analyte, after correcting the total measured
concentration, A, from the fortified sample for the
background concentration, B, measured in the unfortified
sample, i.e.:
R = 100 (A - B) / C,
where C is the fortifying concentration. The recoveries of
all analytes being determined must fall between 75 % and 125
% and the recoveries of at least 90% of these analytes must
fall between 80 % and 120 %. This criteria is applicable to
both external and internal standard calibrated quantitation.
9.6.5 If a recovery falls outside of this acceptable range, a
matrix induced bias can be assumed for the respective analyte
and the data for that analyte in that sample matrix must be
reported to the data user as suspect.
9.6.6 If the unfortified matrix has analyte concentrations equal to
or greater than the concentration fortified, a duplicate
sample vial needs to be fortified at a higher concentration.
If no such sample is available the recovery data for the LFM
sample should not be reported for this analyte to the data
user.
9.7 FIELD DUPLICATES (FD1 and FD2). The laboratory must analyze a field
sample duplicate for a minimum of 10% of the total number of field
samples or at least one field sample duplicate per sample set,
whichever is greater. Duplicate results must not reflect a relative
percent difference (RPD as defined below) greater than 25% for any
one analyte and the RPD for 90% of the analytes being determined
must be less than 20%.
RPD
(FD1 - FD2)
((FD1 + FD2) / 2)
X 100
551.1-22
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where FD1 and FD2 represent the quantified concentration on an
individual analyte for the initial and duplicate field sample
analysis, respectively. If this criteria is not met the analysis
must be repeated. Upon repeated failure, the sampling must be
repeated or the analyte out of control must be reported as suspect
to the data user.
9.8 ASSESSING SURROGATE RECOVERY
9.8.1 The surrogate analyte is fortified into the aqueous portion
of all calibration standards, quality control samples and
field samples. By monitoring the surrogate response, the
analyst generates useful quality control information from
extraction precision through quantitative analysis.
Deviations in surrogate recovery may indicate an extraction
problem. If using external standard calibration the
surrogate retention time functions as a reference for
identification of target analytes.
9.8.2 Using the mean surrogate response from the calibration
standard analyses (Cal<.R), determine the surrogate percent
recovery (%RECS) in all calibration standards, LFBs, and
LFMs, and field samples. This recovery is calculated by
dividing the surrogate response from the sample (SamSR) by
the mean response from the initial calibration standards
(Sect. 10.2 or 10.3) and multiplying by 100, as shown below.
*,
SamSR
% RECS = x 100
Ca1SR
Recoveries must fall within the range of 80% to 120%. If a
sample provides a recovery outside of this range, the extract
must be reanalyzed. If upon reanalysis, the recovery
continues to fall outside the acceptable range a fresh sample
should be extracted and analyzed. If this is not possible
the data for all the analytes from this sample should be
reported to the data user as suspect due to surrogate
recovery outside acceptable limits.
9.8.3 If consecutive samples fail the surrogate response acceptance
criterion, immediately analyze a continuing calibration
standard.
9.8.3.1 If the continuing calibration standard provides a
recovery within the acceptable range of 80% to 120%,
then follow procedures itemized in Sect. 9.8.2 for
each sample failing the surrogate response
criterion.
9.8.3.2 If the check standard provides a surrogate recovery
which falls outside the acceptable range or fails
551.1-23
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the acceptance criteria specified in Sect. 10.4 for
the target analytes, then the analyst must
recalibrate, as specified in Sect. 10.
9.9 ASSESSING THE INTERNAL STANDARD (IS)
9.9.1 When using the internal standard calibration procedure, the
analyst must monitor the internal standard response (peak
area or peak height) of all samples during each analysis day.
The internal standard response should not deviate from mean
internal standard response of the past five continuing '
calibration standards by more than 20%. ..
9.9.2 If > 20% deviation occurs wiith an individual extract,
optimize instrument performance and inject a second aliquot
of that extract.
9.9.2.1 If the reinjected aliquot produces an acceptable
internal standard response, report results for that
aliquot.
9.9.2.2 If a deviation of greater than 20% is obtained for
the reinjected extract, analysis of a calibration
check standard must be performed (Sect. 10.4).
9.9.3 If consecutive samples fail this IS response acceptance
criterion, immediately analyze a calibration check standard.
9.9.3.1 If the check standard provides ,a response factor
(RF) within 20% of the predicted value for the
internal standard and the criteria for all the
target analytes as specified in Sect. .10.4 is met,
the previous sample(s) failing the IS response
criteria need to be reextracted provided the sample
is still available.1 In the event that reextraction
is not possible, report results obtained from the
reinjected extract (Sect 9.9.2) but annotate as
suspect due to internal standard recovery being
outside acceptable limits.
9.9.3.2 If the check standard provides a response factor
which deviates more than 20% of the predicted value
for the internal standard or the criteria for the
target analytes, as specified in Sect 10.4 are not
met, then the analyst must recalibrate, as specified
in Sect. 10.3 and a;ll samples analyzed since the
previous calibration check standard need to be
reanalyzed.
9.10 CONFIRMATION COLUMN ANALYSIS. If a positive result is observed on
the primary column, a confirmation analysis should be performed
using either the confirmation column or by GC/MS.
551.1-24
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9.11 The laboratory may adapt additional quality control practices for
use with this method. The specific practices that are most
productive depend upon.the needs of the laboratory and the nature of
the samples. For example, field reagent blanks may
be used to assess contamination of samples under
site conditions, transportation and storage.
9.12 Quality control samples (QCS) from an outside source, as defined in
i>ect. 3.12, should be analyzed at least quarterly.
10. CALIBRATION AND STANDARDIZATION
10.1 PREPARATION OF CALIBRATION STANDARDS
10.1,1 Five calibration standards are required. One should contain
the analytes at a concentration near to but greater than the
method detection limit (Table 2} for each compound; the
others should be evenly distributed throughout the
concentration range expected in samples or define the working
range of the detector. Guidance on the number of standards
is as follows: A minimum of three calibration standards are '
required to calibrate a range of a factor of 20 in
concentration. For a factor of 50 use at least four
standards, and for a factor of 100 at least five standards
For example, if the MDL is 0.1 /zg/L, and a sample
concentrations are expected to range from 1.0 jug/I to 10 0
jjg/L, aqueous standards should be prepared at 0 20 uq/L *0 80
/ig/L, 2.0 ./ig/L, 5.0 /tg/L, and 15.0 ftg/l.- *' '
10.1.2 As a means of eliminating any matrix effects due to the use
of the phosphate buffer and dechlorinating agents the
procedural calibration standards are prepared in reagent
water which has been buffered to pH 5.2 and dechlorinated
with ammonium chloride. To prepare this
buffered/dechlorinated reagent water, add 5.0 g of phosphate
buffer/dechlorinating agent (Sect 7.1.7.4, ammonium chloride
type) to 500 mL of reagent water (Sect. 7.2).
10.1.3 Next add 25 /yL of the desired concentration primary dilution
standards (acetone and methanol based, Sect. 7.4) to a 50 ml
aliquot of the buffered/dechlorinated reagent water in a 60-
r !u \ , a 50~/zL micro syringe and rapidly inject 25 ul
of the standard into the middle point of the water volume
M 2Ve ^erneed1e as quickly as possible after injection.'
Next, add 50 //L of the surrogate standard solution (Sect
7.4.1) in the same manner. Mix by slowly and carefully
inverting the sample vial two times with minimal sample
agitation. Aqueous standards must be prepared fresh daily
and extracted immediately after preparation (Section 11.2).
10.1.3.1 By including chloral hydrate into the total NH,C1
analyte matrix, .a separate calibration standard
551.1-25
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analysis for Na2S03 preserved reagent water
fortified with chloral hydrate is avoided. Chloral
hydrate is included in'the buffered/NH4Cl
dechlorinated reagent water, containing all the
other target analytes since no matrix induced
recovery problems have been found from reagent water
preserved with NH4C1. Warning! Do not attempt to
analyze chloral hydrate in field samples preserved
with NH4C1, low recoveries may result due to matrix
effects.
10.1.4 CAUTION - DO NOT prepare procedural calibration standards in
1 a volumetric flask and transfer the sample to an extraction
vial either directly for weight determination of volume or
into a graduated cylinder with a subsequent additional
transfer into the extraction vial. Volatility experiments
reflected as much as,a 30 % loss in volatile low molecular
weight analytes following such transfers. All fortified
samples and field samples mu$t be extracted in the vial or
bottle in which they were fortified and collected.
10.2 EXTERNAL STANDARD CALIBRATION PROCEDURE
10.2.1 Extract and analyze each calibration standard according to
Section 11 and tabulate peak height or area response versus
the concentration of the standard. The results are used to
prepare a calibration curve for each compound by plotting the
peak height or area response versus the concentration. This
curve can be defined as either first or second order.
Alternatively, if the ratio of response to concentration
(response factor) is constant over the working range (< 10%
relative standard'deviation,[RSD]), linearity through the
origin can be assumed, and the average ratio or calibration
factor can be used in place of a calibration curve.
10.2.2 Surrogate analyte recoveries must be verified as detailed in
Sections 9.8.
10.3 INTERNAL STANDARD (IS) CALIBRATION PROCEDURE
10.3.1 Extract each calibration standard according to Section 11.
Remove a 1.00 mL portion of ;the MTBE or pentane extract from
the sample extraction vial and place this into a 2.0-mL
autosampler vial. To this extract, add the 10 //L of the
internal standard primary dilution standard, cap the vial and
analyze. Following analysis, tabulate peak height or area
responses against concentration for each compound and the
internal standard. Calculate relative response factor (RRF)
for each compound using Equation 1.
551.1-26
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Equation 1
RRF = j
where
(A,.) (C.)
As = Response for the analyte to be measured
Ais = Response for the internal standard
C-s = Concentration of the internal standard
Cs = Concentration of the analyte to be measured (fJ.g/1)
If RF value over the working range is constant (< 10% RSD),
the average RF can be used for calculations. Alternatively,
the results can be used to plot a calibration curve of
response versus analyte ratios, As/Ais vs. Cs.
10.4 CONTINUING CALIBRATION CHECK STANDARD
10.4.1 Preceding each analysis set, after every tenth sample
analysis and after the final sample analysis, a calibration
standard should be analyzed as a continuing calibration
check. These check standards should be at two different
concentration levels to verify the calibration curve. This
criteria is applicable to both external and internal standard
calibrated quantitation. Surrogate and internal standard
recoveries must be verified as detailed in Sections 9.8 and
9.9, respectively.
10.4.2 In order for the calibration to be considered valid, analyte
recoveries for the continuing calibration check standard must
fall between 75 % and 125 % for all the target analytes. The
recoveries of at least 90% of the analytes determined must
fall between 80% and 120%
10.4.3 If this criteria cannot be met, the continuing calibration
check standard is reanalyzed in order to determine if the
response deviations observed from the initial analysis are
repeated. If this criteria still cannot be met then the
instrument is considered out of calibration for those
specific analytes beyond the acceptance range. The
instrument needs to be recalibrated and the previous samples
reanalyzed or those analytes out of acceptable range should
be reported as suspect to the data user for all the
previously analyzed samples.
11. PROCEDURE
11.1 SAMPLE PREPARATION
11.1.1 Remove samples from storage and allow them to equilibrate to
room temperature.
551.1-27
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11.1.2 Remove the vial caps. Remove a 10 ml volume of the sample.
Check the pH of this 10 ml aliquot to verify that it is
within a pH range of 4.5 anc'l 5.5. If the pH is out of this
range a new sample must be collected. Replace the vial caps
and weigh the containers with contents to the nearest 0.1 g
and record these weights for subsequent sample volume
determination. (See Sect. 11.2.4 for continuation of
weighing and calculation of true volume). Alternatively, the
sample vials may be precalibrated by weighing in 50 ml of
water and scoring the meniscus on the bottle. This will
eliminate the gravimetric step above and in Sect. 11.2.4.
11.1.3 Inject 50//L of the surrogate analyte fortification solution
(Sect. 7.4.1) into the sample. The aqueous concentration of
surrogate analyte must be tHe same as that used in preparing
calibration standards (Sect. 9.1.3). Mix by slowly and
carefully inverting the sample vial two times with minimal
sample agitation.
11.2 SAMPLE EXTRACTION i
11.2.1 WITH MTBE AS EXTRACTION SOLVENT
11.2.1.1 After addition of the surrogate (Sect 11.1.3) add
exactly 3.0 mL of MTBE with a type A, TD, transfer
or automatic dispensing pipet.
11.2.1.2 Add 10 g NaCl or 20 g Na2S04 to the sample vial.
(See Section 13.7 for an important notice concerning
the use of NaCl when analyzing for DBFs.) Recap and
extract the NaCl or Na2SO, /MTBE/sample mixture by
vigorously and consistently shaking the vial by hand
for 4 min. Invert the vial and allow the water and
MTBE phases to separate (approx. 2 min).
If a series of samples are being prepared for
extraction using Na2S04, immediately after the
addition of the Na2504, the sample should be
recapped, agitated and placed in a secure horizontal
position with the undissolved Na,SO, distributed
along the length of the vial. If trie vial is left
in a vertical position, while additional samples
have solvent and salt added, the Na2S04 will
solidify in the bottom of the vial and it will not
dissolve during sample extraction.
NOTE: Previous versions of this method call for the
addition of the salt by "shaking the vial
vigorously" before the MTBE has been added. Please
make a note that this procedural order has been
changed in an effort to minimize volatile analyte
losses.
551.1-28
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11.2.1.3 By using a disposable Pasteur pipet (Sect. 6.2),
transfer a portion of the solvent phase from the 60-
mL vial to an autosampler vial (Sect. 6.2). Be
certain no water has carried over onto the bottom of
the autosampler vial. If a dual phase appears in
the autosampler vial, the bottom layer can be easily
removed and discarded by using a Pasteur pipet. The
remaining MTBE phase may be transferred to a second
autosampler vial as a backup extract or for separate
confirmation analysis. Approximately 2.5 ml of the
solvent phase can be conveniently transferred from
the original 3 ml volume.
11.2.1.3.1 If using an internal standard
quantitation, the extract transfer into
the autosampler vial must be performed
in a quantitative manner. This may be
done using a 1.00 ml syringe or a 2.00-
mL graduated disposable pipet to
accurately transfer 1.00 mL o.f sample
extract to the autosampler vial where 10
//L of internal standard primary dilution
standard (Sect. 7.4.2) solution can be
added.
11.2.2 WITH PENTANE AS EXTRACTION SOLVENT
11.2.2.1 After addition of the surrogate (Sect 11.1.3) add
exactly 5.0 mL of pentane with a type A, TD,
transfer or automatic dispensing pipet.
11.2.2.2 Add 20 g Na2S04 to the sample vial. Recap and
extract the Na2S04/pentane/sample mixture by
vigorously and consistently shaking the vial by hand
for 4 min. Invert the vial and allow the water and
pentane phases to separate (approx. 2 min). NOTE:.
Previous versions of this method call for the
addition of NaCl by "shaking the vial vigorously"
before the pentane has been added. Please make a'
note that this procedural order has been changed in
an effort to minimize.volatile analyte losses. If a
series of samples are being prepared for extraction,
immediately after the addition of the Na2S04, the
sample should be recapped, agitated and placed in a
secure horizontal position with the undissolved
Na2S04 distributed along the length of the vial. If
the vial is left in a vertical position, while
additional samples have solvent and salt added, the
Na2SO^ will solidify in the bottom of the vial and
it will not dissolve during sample extraction.
551.1-29
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11.2.2.3 Using a disposable Pasteur pipet, transfer a portion
of the solvent phase from the 60-mL vial to an
autosampler vial,. Be certain no water has carried
over onto the bottom of the autosampler vial. If a
dual phase appeals in the autosampler vial, the
bottom layer can be easily removed and discarded
using a Pasteur pipet. The remaining pentane phase
may be transferred to a second autosampler vial as a
backup extract or for separate confirmation
analysis.
11.2.2.3.1 The extract transfer into the
autosampler vial must be performed in a
quantitative manner. This may be done
using a 1.00-mL syringe or a 2.00-mL
graduated disposable pipet to accurately
transfer 1.00 ml of sample, extract to
the autosampler vial where 10 /A. of
internal standard primary dilution
standard (Sect. 7.4.2) solution can be
added.
11.2.3 Discard the remaining contents of the sample vial. Shake off
the last few drops with short, brisk wrist movements.
11.2.4 Reweigh the empty vial with the original cap and calculate
the net weight of sample iby difference to the nearest 0.1 g
(Sect. 11.1.2 minus Sect. 11.2.4). This net weight (in
grams) is equivalent to the volume of water (in ml)
extracted, Vs.
11.2.5 The sample extract may be stored in a freezer (<-10°C) for a
maximum of fourteen days before chromatographic analysis but
no more than 24 hours at room temperature (i.e. on an
autosampler rack). Due to the volatility of the extraction
solvent, if the septum on a vial has been pierced, the crimp
top or screw cap septum needs to be replaced immediately or
the extract cannot be reanalyzed at a later time.
11.3 SAMPLE ANALYSIS
11.3.1 The recommended GC operating conditions are described in
6.9.2.1 and 6.9.2.2 along with recommended primary and
confirmation columns. Retention data for the primary and
confirmation columns are given in Table 1.
11.3.2 Inject 2 /zL of the sample extract and record the resulting
peak response. For optimum performance and precision, an
autosampler for sample injection and a data system for signal
processing are strongly recommended.
551.1-30
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12. DATA ANALYSIS AND CALCULATIONS
12.1 Identify sample components by comparison of retention times to
retention data from the calibration standard analysis. If the
retention time of an unknown compound corresponds, within limits
(Sect. 12.2), to the retention time of a standard compound, then
identification is considered positive.
12.2 The width of the retention time window used to make identifications
should be based upon measurements of actual retention time
variations of standards over the course of a day. Three times the
standard deviation of a retention time can be used to calculate a
suggested window size for a compound. However, the experience of
the analyst should weigh heavily in the interpretation of
chromatograms. Use the initial demonstration of capability
retention time data as an initial means of determining acceptable
retention time windows. Throughout the development of this method a
retention time window of 1.0 % of the total analyte retention time
was used.
12.3 Identification requires expert judgment when sample components are
not resolved chromatographically, that is, when GC peaks obviously
represent more than one sample component (i.e., broadened peak with
shoulder(s) or valley between two or more maxima). Whenever doubt
exists over the identification of a peak in a chromatogram,
confirmation is suggested by the use of a dissimilar column or by
GC-MS when sufficient concentrations of analytes are present.
12.4 If the peak response exceeds the linear range of the calibration
curve, the final extract should be diluted with the appropriate
extraction solvent and reanalyzed. The analyst is not permitted to
extrapolate beyond the concentration range of the calibration curve.
12.5 Calculate the uncorrected concentrations (Cf) of each analyte in the
sample from the response factors or calibration curves generated in
Sect. 10.2.1 or 10.3.1. do not use the daily calibration check
standard to calculate amounts of method analytes in samples.
12.6 Calculate the corrected sample concentration as:
Concentration, /ig/L = C- x 50 ,
Vs
where the sample volume, Vs in mL, is equivalent to the net sample
weight in grams determined in Sect. 11.1.2 and Sect. 11.2.4.
13. METHOD PERFORMANCE
13.1 In a single laboratory, analyte recoveries from reagent water with
MTBE as the extracting solvent, were determined at three
concentration levels, Tables 2A through 4B. Results from the lowest
fortified level were used to determine the analyte MDLs-(11) listed
551.1-31
-------
in Table 2. These MDLs along with the estimated detection limit
(EDL) were determined in the following manner. EDLs are provided
for informational purposes.
13.1.1 For each analyte, calculate the mean concentration and the
standard deviation of this mean between the seven replicates.
Multiply the student's t-value at 99% confidence and n-1
degrees of freedom (3.143 for seven replicates) by this
standard deviation to yield a statistical estimate of the
detection limit. This estimate is the MDL.
13.1.2 Since the statistical estimate is based on the precision of
the analysis, an additional estimate of detection can be
determined based upon themoise and drift of the baseline as
well as precision. This estimate, known as the "EDL" is
defined as either the MDL or a level of compound in a sample
yielding a peak in the final extract with a,signal to noise
(S/N) ratio of approximately 5, whichever is greater.
13.1.3 These MDL determinations were conducted on both the primary
(DB-1) and the confirmation (Rtx-1301) columns and are
presented in Tables 2.A. through 2.D.
13.2 Analyte recoveries were also determined for reagent water with
pentane as the extracting solvent. Two concentration levels were
studied and the results are presented in Tables 8 and 9. Results
from the lowest fortified level were used to determine the analyte
MDLs (11) listed in Table 8. These MDLs along with the estimated
detection limit (EDL) were determined in a manner analogous to that
described in Sect. 13.1.1 through 13.1.2.
13.3 In a single laboratory, method precision and accuracy were evaluated
using analyte recoveries from replicate buffered/dechlorinated (both
NH,C1 and Na2S03) matrices with MTBE as the extracting solvent. The
matrices studied included; fulvic acid fortified reagent water and
ground water displaying a high CaCO, content. The results for these
are presented in Tables 3.A. through 6.B. These matrices were
fortified using outside source analyte solutions (except for the
pesticides and herbicides) to assess accuracy and eight replicate
analyses were conducted to assess precision.
13.4 Holding time studies were conducted for buffered/dechlorinated
reagent water and tap water. Holding studies were also conducted on
MTBE sample extracts from these two matrices. Results indicated
that analytes were stable in these water matrices stored at 4°C.
13.5 MTBE and pentane extracts holding studies indicated the analytes
were stable for 14 days when stored in a freezer at <-10°C.
13.6 Chromatograms of a fortified, buffered/NH4Cl dechlorinated reagent
water extract are presented as Figures 1 through 3. In the
chromatograms of Figures 1 and 2, the elution of the method analytes
551.1-32
-------
from a MTBE extract can be seen on the primary DB-1 column and the
confirmation Rtx-1301 column, respectively. Figure 3 shows the
elution of the method analytes from a pentane extract, using a
modified temperature program, on the primary DB-1 column. Analyte
numerical peak identification, retention time and fortified
concentrations are presented for information purposes only in Tables
10, 11 and 12 for Figures 1, 2 and 3, respectively.
13.7 IMPORTANT NOTICE: All demonstration data presented in Section'17
using MTBE as the extracting solvent, was obtained using NaCl as the
salt. A recent report (19) indicated elevated recoveries (via
synthesis) of some brominated DBPs when NaCl was used in the
extraction process, due to the inevitable presence of bromide
impurities in the NaCl. This phenomenon has been confirmed by the
authors of this method in samples from chlorinated water systems
that were not extracted immediately after the NaCl was added.
Significant effects can be seen if extraction is delayed for as
little as 15 minutes after the addition of the NaCl. For this
reason, the use of Na?SO, is strongly recommended over NaCl for MTBE
extraction of DBPs. Although less method validation data have been
obtained for the Na2S04 option, sufficient data have been collected
to indicate that it is equivalent or superior to NaCl in salting out
the method analytes, and has no observed negative effect on
precision or accuracy.
14. POLLUTION PREVENTION
14.1 This method is a micro-extraction procedure which uses a minimal
amount of extraction solvent per sample. This microextraction
procedure reduces the hazards involved with handling large volumes
of potentially harmful organic solvents needed for conventional
liquid-liquid extractions.
14.2 For information about pollution prevention that may be applicable to
laboratory operations, consult "Less is Better: Laboratory Chemical
Management for Waste Reduction", available from the American
Chemical Society's Department of Government Relations and Science
Policy, 1155 16th Street N.W., Washington, D.C. 20036.
15. WASTE MANAGEMENT ,
15.1 Due to the nature of this method, there is little need for waste
management. No large volumes of solvents or hazardous chemicals are
used. The matrices of concern are finished drinking water or source
water,. However, the Agency requires that laboratory waste
management practices be conducted consistent with all applicable
rules and regulations, and that laboratories protect the air, water,
and land by minimizing and controlling all releases from fume hoods'
and bench operations. Also, compliance is required with any sewage'
discharge permits and regulations, particularly the hazardous waste
identification rules and land disposal restrictions. For further
information on waste management, consult "The Waste Management
551.1-33
-------
Manual for Laboratory Personnel,",also available from the American
Chemical Society at the address in Sect. 14.2.
16. REFERENCES '
1. Glaze, W.W., Lin, C.C., "Optimization of Liquid-Liquid Extraction
Methods for Analysis of Organics in Water", EPA-600/S4-83-052, U.S.
Environmental Protection Agency, January 1984.
2. Richard, J.J., Junk, G.A., "Liquid Extraction for Rapid
Determination of Halomethanes in Water," Journal AWWA. 69, 62, 1977.
3. Reding, R., P.S. Fair, C.J. Shipp, and H.J. Brass, "Measurement of
Dihaloacetonitriles and Chloropicrin in Drinking Water",
" Disinfection Byproducts: Current Perspectives ", AWWA, Denver,CO
1989.
4. Hodgeson, J.W., Cohen, A.L. and Collins, J. P., "Analytical Methods
for Measuring Organic Chlorination Byproducts" Proceedings Water
Quality Technology Conference (WQTC-16), St. Louis, MO, Nov. 13-17,
1988, American Water Works Association, Denver, CO, pp. 981-1001.
5. Henderson, J.E., Peyton, G.R. and Glaze, W.H. (1976). In
"Identification and Analysis of Organic Pollutants in Water" (L.H.
Keith ed.), pp 105-111. Ann Arbor Sci. Pub!., Ann Arbor, Michigan.
6. Fair, P.S., Barth, R.C., Flesch, J.J. and Brass, H., "Measurement of
Disinfection Byproducts in Chlorinated Drinking Water," Proceedings
Water Quality Technology Conference (WQTC 15), Baltimore, MD, None.
15-20, 1987, American Water Works Association, Denver, CO, pp 339-
353
7. Trehy, M.L. and Bieber, T.I. (1981). In " Advances in the
Identification and Analysis of Organic Pollutants in Water II" (L.H.
Keith, ed.) pp 941-975. Ann Arbor Sci. Publ., Ann Arbor, Michigan.
8. Oliver, B.G., "Dihaloacetonitriles in Drinking Water: Algae and
Fulvic Acid as Precursors," Environ. Sci. Techno!, 17, 80, 1983.
9. Krasner, S.W., Sclimenti, M.J. and Hwang, C.J., "Experience with
Implementing a Laboratory Program to Sample and Analyze for
Disinfection By-products in a National Study," Disinfection By-
products: Current Perspectives. AWWA, Denver, CO, 1989.
10. Munch, J. W., "Method 525.2-Deterrni nation of Organic Compounds in
Drinking Water by Liquid-Solid Extraction and Capillary Column
Chromatography/ Mass Spectrometry" in Methods for the Determination
of Organic Compounds in Drinking Water; Supplement 3 (1995).
USEPA, National Exposure Research Laboratory, Cincinnati, Ohio
45268.
551.1-34
-------
11. Munch, J.W., "Method 524.2- Measurement of Purgeable Organic
Compounds in Water by Capillary Column Gas Chromatography/ Mass
Spectrometry" in Methods for the Determination of Organic Compounds
in Drinking Water; Supplement 3 (1995). USEPA, National Exposure
Research Laboratory, Cincinnati, Ohio 45268.
12. Glaser, J.A., Foerst, D.L., McKee, G.D., Quave, S.A. and Budde, W.L.
"Trace Analysis for Wastewaters", Environ. Sci. Technol.. 15. 14£6,
1981. ~~ ~"
13. ASTM Annual Book of Standards, Part 11, Volume 11.02, D3694-82,
"Standard Practice for Preparation of Sample Containers and for
Preservation," American Society for Testing and Materials,
Philadelphia, PA, 1986.
14. Bellar, T.A., Stemmer, P., Lichtenburg, J.J., "Evaluation of
Capillary Systems for the Analysis of Environmental Extracts," EPA-
600/S4-84-004, March 1984.
15. "Carcinogens-Working with Carcinogens", Publication No. 77-206,
Department of Health, Education, and Welfare, Public Health Service,
Center for Disease Control, National Institute of Occupational
Safety and Health, Atlanta, Georgia, August 1977.
16. "OSHA Safety and Health Standards, General Industry", (29CFR1910),
OSHA 2206, Occupational Safety and Health Administration,
Washington, D.C. Revised January 1976.
17. "Safety in Academic Chemistry Laboratories", 3rd Edition, American
Chemical Society Publication, Committee on Chemical Safety,
Washington, D.C., 1979.
18. Cole, S., Henderson, D. "Atrazine and Simazine - Product Redesign
improves Stability". The Reporter, Volume 13, No. 6, 1994, pg 12.
Trade publication from Supelco, Inc.
19. Xie, Yuefeng, "Effects of Sodium Chloride on DBP Analytical
Results," Extended Abstract, Division of Environmental Chemistry,
American Chemical Society Annual Conference, Chicago, IL, Aug. 21-
26, 1995.
551.1-35
-------
TABLE 1. RETENTION TIME DATA USING MTBE
ANALYTE
Chloroform
1 , 1 , 1-Tri chl oroethane
Carbon Tetrachloride
Trichl oroacetoni tri le
Di chl oroacetoni tri 1 e
Bromodichloromethane
Trichloroethylene
Chloral Hydrate
1 , 1-Dichl oro-2-Propanone
1,1,2-Tri chl oroethane
Chloropicrin
Di bromochl oromethane
Bromochl oroacetoni tri 1 e
1,2-Dibromoethane (EDB)
Tetrachl oroethyl ene
1,1, 1-Tri chl oropropanone
Bromoform
Di bromoacetoni tril e
1 , 2,3-Trichl oropropane
l,2-Dibromo-3-chloropropane (DBCP)
Hexachl orocycl opentadi ene
Trifluralin
Simazine
Atrazine
Hexachl orobenzene
Lindane (gamma-BHC)
Metribuzin
Bromacil
Column Aa
Retention Time
minutes
7.04
8.64
9.94
10.39
12.01
12.42
12.61
13.41
14.96
19.91
23 . 10
23.69
24.03
24.56
26.24
27.55
29.17
29.42
30.40
35.28
40.33
45.17
46.27
46.55 .
47.39
47.95.
150.25
152.09
Column Bb
Retention Time
minutes
7.73
7.99
8.36
10.35
25.21
15.28
11.96
NR c
20.50
25.01
23.69
26.32
29.86
26.46
24.77
28.47
30.36
32.77
31.73
36.11
39.53
45.43
48.56d
48.56d
46.47
49.68
53.92
59.60
551.1-36
-------
TABLE 1. RETENTION TIME DATA USING MTBE (cont'd)
ANALYTE
Column Aa
Retention Time
minutes
Column Bb
Retention Time
minutes
Alachlor
Cyanazine
Heptachlor
Metolachlor
Heptachlor Epoxide
Endrin
Endrin Aldehyde
Endrin Ketone
Methoxychlor
Surrogate:
Decaf luorobiphenyl
Internal Standard:
52.25
53.43
53.72
55.44
58.42
64.15
65.46
72.33
73.53
36.35
31.00
54.38
59.89
53.15
57.07
59.05
65.24
71.56
81.28
76.73
36.28
31.30
Bromof1uorobenzene
(a) Column A - 0.25 mm ID x 30 m fused silica capillary with chemically
bonded methyl polysiloxane phase (J&W, DB-1, 1.0 /zm film
thickness or equivalent). The linear velocity of the
helium carrier is established at 25 cm/sec at 35°C.
The column oven is temperature programmed as follows:
[1] HOLD at 35°C for 22 min
[2] INCREASE to 145°C at 10°C/min and hold at 145°C for 2 min
[3] INCREASE to 225°C at 20°C/min and hold at 225°C for 15 min
[4] INCREASE to 260°C at 10°C/min and hold at 260°C for 30
min.. or until all expected compounds have eluted.
Injector temperature: 200°C
Detector temperature: 290°C
(b) Column B -
0.25 mm ID x 30 m with chemically bonded 6 %
cyanopropylphenyl/94 % dimethyl polysiloxane phase
(Restek, Rtx-1301, 1.0 jum film thickness or equivalent).
The linear velocity of the helium carrier gas is
established at 25 cm/sec at 35°C.
The column oven is temperature programmed exactly as indicated
for column A, above. The same temperature program is utilized
to allow for simultaneous confirmation analysis.
(c)
There is no retention time for this analyte since it does not separate
into a discreet peak on the Rtx-1301.
(d) Atrazine and simazine coelute on the confirmation column.
551.1-37
-------
TABLE 2. A.
NH,C1 PRESERVED
METHOD DETECTION LIMIT USING MTBE
REAGENT WATER ON PRIMARY DB-1 COLUMN
ANALYTE
Alachlor
Atrazine
Bromacil
Bromochl oroaceton i tr i 1 e
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloral Hydrate
Chloropicrin
Chloroform
Cyanazine
Di bromoacetoni tr i 1 e
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1 , 2-Di bromoethane
Dichloroacetonitrile
1 , 1-Di chl oro-2-propanone
Endrin
Endrin Aldehyde
Endrin Ketone
Heptachlor
Heptachlor Epoxide
Hexachlorobenzene
Hexachl orocycl opentadi ene
Lindane (g-BHC)
Methoxychlor
Metolachlor
Metribuzin
Simazine
Fort.
Cone. ,
fjg/i
0.327
0.633
0.094
0.010
0.010
0.010
0.010
0.025
0.010
0.050
0.567
0.010
0.010
0.010
0.010
0.010
0.010
0.016
0.022
0.016
0.047
0.044
0.006
0.019
0.009
0.063
0.219
0.062
0.625
Obs£r.a
Cone. ,
fjg/i
0.384
0.764
0.099
0.011
0.012
0.018
0.011
0.029
0.009
0.054
0.757
0.016
0.011
0.020
0.020
0.009
0.0)11
0.023
0.023
0.016
0.062
0.050
0.006
0.019
0.015
0.057
0.254
0.100
0.794
Avg.
%Rec.
117
121
105
110
120
180
110
116
90
108
134
160
110
200
200
90
110
144
105
100
132
114
100
100
167
90
116
161
127
% RSD
2.13
3.56
10.05
5.42
7.50
8.12
6.32
5.61
7.65
34.04
13.93
12.78
4.55
15.15
12.54
4.28
6.22
2.57
2.25
5.14
43.65
1.64
5.44
31.81
9.89
4.85
3.20
12.45
5.95
MDLb
//g/L
0.025
0.082
0.030
0.002
0.003
0.004
0.002
0.005
0.002
0.055
0.316
0.006
0.001
0.009
0.008
0.001
0.002
0.002
0.002
0.002
0.081
0.002
0.001
0.018
0.004
0.008
0.024
0.037
0.142
EDLC
//g/L
0.500
0.324
0.055
0.009
0.005
0.006
0.004
0.011
0.014
0.075
0.685
0.010
0.007
0.009
0.008
0.005.
0.007
0.011
0.010
0.020
0.081
0.030
0.006
0.022
0.016
0.046
0.146
0.037
0.431
551.1-38
-------
TABLE 2.A. METHOD DETECTION LIMIT USING MTBE (cont'd)
NHAC1 PRESERVED REAGENT HATER ON PRIMARY DB-1 COLUMN
ANALYTE
Tetrachl oroethyl ene
Tri chl oroacetoni tri 1 e
1,1, 1-Tri chl oroethane
1,1, 2-Tri chl oroethane
Tri chl oroethyl ene
1,2,3-Trichloropropane
1,1, 1-Tri chl oro-2-propanone
Trifluralin
Surrogate ===>
Decafl uorobyphenyl
Fort.
Cone. ,
^g/L
0.
0.
0.
0.
0.
0.
0.
0.
10.
010
010
010
140
010
156
010
022
0
(a) Based upon the analysis of eight
(b) MDL designates the statistically
Obser.a
Cone. ,
//g/L
0.012
0.010
0.013
0.124
0.008
0.137
0.027
0.026
10.8
Avg.
%Rec.
120
100
130
89
80
88
270
118
108
replicate MTBE
derived MDL and
%
5
5
12
3
8
1
20
3
2
RSD
.04
.31
.35
.27
.68
.95
.53
.89
.38
sample
is cal
0
0
0
0
0
0
0
0
MDLb
//g/L
.002
.002
.005
.012
.002
.008
.016
.003
extracts
culated
0
0
0
0
0
0
0
0
by
EDLC
.004
.004
.005
.040 ;
.008
.028
.016
.010
multiplying the standard deviation of the eight replicates by the
student's t-value (2.998) appropriate for a 99% confidence level and a
standard deviation estimate with n-1 degrees of freedom.
(c) Estimated Detection Limit (EDL) — Defined as either the MDL or a level
of compound in a sample yielding a peak in the final extract with a
signal to noise (S/N) ratio of approximately 5, whichever is greater.
551.1-39
-------
TABLE 2.B. METHOD DETECTION LIMIT USING MTBE
NH,C1 PRESERVED REAGENT HATER ON CONFIRMATION Rtx-1301
COLUMN
ANALYTE
Alachlor
Bromacil
Bromochl oroacetoni tri 1 e
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloropicrin
Chloroform
Cyanazine
Di bromoacetoni tri 1 e
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1 , 2-Di bromoethane
Di chl oroacetoni tri le
l,l-Dichloro-2-propanone
Endrin
Endrin Aldehyde
Endrin Ketone
Heptachlor
Heptachlor Epoxide
Hexachl orobenzene
Hexachl orocycl opentadi ene
Lindane (g-BHC)
Methoxychlor
Metolachlor
Metribuzin
Simazine/Atrazine
Tetrachl oroethyl ene
Tri chl oroacetoni tri 1 e
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
Fort.
Cone. ,
//g/L
.109
.094
.010
.010
.010
.010
.010
.010
.189
.010
.010
.010
.010
.010
.010
.016
.022
.047
.016
.044
.006
.019
.009
.188
.219
.062
.26 e
.010
.010
Obser.3
Cone. ,
0g/L
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
,0
0
0
0
0
0
0
0
1
0
0
.107
.134
.008
.012
.015
.0.11
NR d
.059
.279
.010
.021
.020
.039
.010
.009
.0,25
.034
.049
.018
.079
.006
NR
.011
.221
.280
.(#6
.619
.012
.006
Avg.
%Rec.
98
143
80
120
150
110
NR
590
148
100
210
200
390
100
90
156
155
104
113
180
100
NR
122
118
128
123
129
120
60
%RSD
1.
11.
9.
4.
29.
18.
70
65
49
34
51
70
MDLb
fjg/i
0
0
0
0
0
0
NR
2.
7.
4.
29.
9.
6.
4.
11.
4.
22.
5.
3.
84.
16.
82
56
87
30
95
44
11
65
09
45
49
79
71
47
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.005
.047
.002
.002
.013
.006
NR
.005
.063
.001
.018
.006
.007
.001
.003
.003
.023
.008
.002
.202
.003
NR
6.
3.
1.
2.
2.
6.
16.
09
53
45
17
48
97
01
0
0
0
0
0
0
0
.002
.023
.012
.005
.121
.002
.003
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
d
0
0
0
0
0
0
0
EDL°
/>g/L
.076
.071
.015
.006
.013
.006
.062
.008
.065
.007
.018
.024
.007
.003
.015
.015
.030
.047
.010
.202
.011
.327 .
.009
.041
.268
.013
.629
.003
.010
551.1-40
-------
TABLE 2.B. METHOD DETECTION LIMIT USING MTBE (cont'd)
ANALYTE
1,1, 1-Tri chl oroethane
1,1, 2-Tri chl oroethane
Trichloroethylene
1,2, 3-Tri chl oropropane
1,1, 1-Tri chl oro-2-propanone
Trifluralin
Fort.
Cone. ,
y^g/L
0
0
0
0
0
0
.010
.140
.010
.156
.010
.022
Obser.a
Cone. ,
/jg/i
0
0
0
0
0
0
.020
.133
.009
.160
.011
.024
Avg.
%Rec .
200
95
90
103
110
109
%RSD
19
3
13
3
7
3
.22
.40
.77
.11
.11
.07
MDLb
/vg/L
0
0
0
0
0
0
.012
.014
.004
.015
.002
.002
EDLC
0.
0.
0.
0.
0.
0.
012
020
007
114
010
006
Surrogate ===> 10.0 10.6 106 1.78
Decaf1uorobyphenyl
(a) Based upon the analysis of eight replicate MTBE sample extracts. ;
(b) MDL designates the statistically derived MDL and is calculated by
multiplying the standard deviation of the eight replicates by the
student's t-value (2.998) appropriate for a 99% confidence level and a
standard deviation estimate with n-1 degrees of freedom.
(c) Estimated Detection Limit (EDL) — Defined as either the MDL or a
level of compound in a sample yielding a peak in the final extract
with a signal to noise (S/N) ratio of approximately 5, whichever is
. greater. .
(d) NR indicates Not Reported since their was no peak detected for the
eight replicate MDL determination.
(e) The concentration of atrazine and simazine were added together for
this determination since these two peaks coelute on the confirmation
column.
551.1-41
-------
TABLE 3.A. PRECISION.AND ACCURACY RESULTS USING MTBEa
NH,C1 PRESERVED FORTIFIED REAGENT WATER ON THE PRIMARY DB-1 COLUMN
ANALYTE
Alachlor
Atrazine
Bromacil
Bromochl oroacetoni tri 1 e
Bromodichloromethane
Bromoform
Carbon Tetrachloride
Chloropicrin
Chloroform
Cyanazine
Di bromoacetoni tri 1 e
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1 , 2-Di bromoethane
Dichl oroacetoni tri le
1 , 1-Di chl oro-2-propanone
Endrin
Endrin Aldehyde
Endrin Ketone
Heptachlor
Heptachlor Epoxide
Hexachlorobenzene
Hexachl orocycl opentadi ene
Lindane (g-BHC)
Methoxychl or
Hetolachlor
Metribuzin
Simazine
Tetrachl oroethyl ene
Tri chl oroacetoni tri le
Fortified ; Mean Meas.
Cone., /yg/L Cone., /yg/L
2.18
12.6
1.88
5.00
5.00 ''•
5.00
5.00 ;
5.00
5.00
3.77
5.00
5.00
5.00
5.00 ;
5.00
5.00
0.311
0.437
0.310 :
0.313
0.875
t
0.124
0.374
0.188
1.26
4.39
1.24 :
12.5
5.00
5.00
2.40
12.4
1.85
5.69
4.94
5.07
5.07
5.32
5.10
3.89
5.78
4.87
5.11
4.96
5.35
5.08
0.337
0.503
0.319
0.351
0.968
0.137
0.368
0.199
1.48
4.89
1.21
13.1
5.07
5.73
%RSD
1.47
1.71
3.13
0.71
1.14
0.72
1.72
1.38
1.30
2.85
1.43
0.71
0.59
0.73
0.57
0.72
1.40
1.32
1.52
2.84
0.65
0.89
1.18
1.41
2.84
0.87
3.94
2.02
1.62
1.34
Percent
Recovery
110
98
98
114
99
101
101
106
102
103
116
97
102
99
107
102
108
115
103
112
111
110
98
106
117
111
97
105
101
115
551.1-42
-------
TABLE 3.A. PRECISION AND ACCURACY RESULTS USING MTBE" (cont'd)
NH.C1 PRESERVED FORTIFIED REAGENT WATER ON THE PRIMARY DB-1 COLUMN
Fortified Mean Meas.
ANALYTE Cone., //g/L Cone., UQ/i
1,1, 1-Trichl oroethane
1, 1,2-Trichloroethane
Trichloroethylene
1,2,3-Trichloropropane
1,1, 1-Tri chl oro-2-propanone
Trifluralin
5.00
2.80
5.00
3.12
5.00
0.439
5.02
2.92
4.87
3.08
5.30
0.503
%RSD
1.22
0.91
1.48
0.62
0.81
1.09 -
Percent
Recovery
100
104
97
99
106
115
Surrogate ===>
Decaf!uprobyphenyl
10.0
10.4
1.93
104
(a) Based upon the analysis of eight replicate MTBE sample extracts.
551.1-43
-------
TABLE 3.B. PRECISION AND ACCURACY RESULTS USING MTBE a
Na,SO, PRESERVED FORTIFIED REAGENT WATER ON THE PRIMARY DB-1 COLUMN
Fortified Mean Meas.
ANALYTE ' Cone., /jg/l Cone., fjg/i
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloral Hydrate
Chloroform
Dibromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1 , 2-Di bromoethane
Tetrachl oroethyl ene
1,1, 1-Tri chl oroethane
Tri chl oroethyl ene
5.00
5.00
5.00 :
1.00
5.00
5.00
5.00
5.00
5.00
5.00 ;
5.00 :
4.91
5.05
5.08
0.93
4.96
4.83
5.07
4.90
5.06
5.01
4.81
%RSD
1,49
1.32
2.24
1.81
1.71
1.43
1.04
1.02
2.53
2.11
2.21
Percent
Recovery
98
101
102
93
99
97
101
98
101
100
96
Surrogate ===>
Decafluorobyphenyl
10.0 10.2 1.88 102
(a) Based upon the analysis of eight replicate MTBE sample extracts.
551.1-44
-------
TABLE 3.C. PRECISION AND ACCURACY RESULTS USING MTBEa
NH4C1 PRESERVED FORTIFIED REAGENT WATER ON THE CONFIRMATION
Rtx-1301 COLUMN
ANALYTE
Alachlor
Bromacil
Bromochl oroacetoni tri le
Bromodichloromethane
Bromoform
Carbon Tetrachloride
Chloropicrin
Chloroform ,
Cyanazine
Di bromoacetoni tr i 1 e
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1,2-Dibromoethane
Dichl oroacetoni tri le
1, l-Dichloro-2-propanone
Endrin
Endrin Aldehyde
Endrin Ketone
Heptachlor
Heptachlor Epoxide
Hexachl orobenzene
Hexachl orocycl opentadi ene
Lindane (g-BHC)
Methoxychlor
Metolachlor
Metribuzin
Simazine/Atrazine
Tetrachl oroethyl ene
Tri chl oroacetoni tri 1 e
Fortified
Cone., jjg/L
2.18
1.88
5.00
5.00
5.00
5.00
5.00
5.00
3.77
5.00
5.00
5.00
5.00
5.00
5.00
0.310
0.440
0.310
0.310
0.880
0.124
0.374 .
0.188
1.26
4.39
1.24
25.1 b
5.00
5.00
Mean Meas.
Cone., //g/L
2.26
1.77
5.59
4.92
5.04
4.90
5.24
5.05
3.90
5.47
5.04
5.12
5.09
5.30
4.94
0.335
0.490
0.317
0.349
0.978
0.135
0.474
0.205
1.42
4.57
1.29
30.0
4.93
5.48
%RSD
0.81
3.50
0.86
1.02
0.73
1.72
1.20
1.20
2.30
0.58
0.90
0.54
1.82
0.55
0.70
2.08
2.13
1.63
1.06
0.80
0.59
7.19
0.75
2.30
3.43
1.15
1.11
1.65
1.31
. Percent
Recovery
104
94
112
98
101
98
105
101
103
109
101
102
102
106
99
108
111
102
113
111
109
127
109
113
104
104
119
99
110
551.1-45
-------
TABLE 3.C. PRECISION AND ACCURACY RESULTS USING MTBE a (cont'd)
NH,C1 PRESERVED FORTIFIED REAGENT WATER ON THE CONFIRMATION
Rtx-1301 COLUMN
ANALYTE
1,1, 1-Tri chl oroethane
1,1, 2-Tri chl oroethane
Trichloroethylene
1,2,3-Trichloropropane
1,1, 1-Tri chl oro-2-propanone
Trifluralin
Fortified
Cone. , //g/L
5.00
2.80
5.00
3.12
5.00
0.440
Mean Meas.
Cone., fjg/L
4.87
2.76
4.87
3.07
4.90
0.486
%RSD
1.66
1.52
1.52
0.88
0.89
0.93
Percent
Recovery
97
98
97 .
98
98
110
1.96
106
Surrogate -==> 10.0 10.6
Decafluorobyphenyl
(a) Based upon the analysis of eight replicate MTBE sample extracts.
(b) Simazine and atrazine coelute on the confirmation column and therefore
there results were added together.
551.1-46
-------
TABLE 3.D. PRECISION AND ACCURACY RESULTS USING MTBE a
Na2S03 PRESERVED FORTIFIED REAGENT WATER ON THE CONFIRMATION
Rtx-1301 COLUMN
ANALYTE
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloroform
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1,2-Dibromoethane
Tetrachl oroethyl ene
1,1,, 1-Trichloroethane
Trichl oroethyl ene
Fortified
Cone. , fjg/L
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
Mean Meas.
Cone. , fjg/L
4.88
5.03
4.90
4.90
5.15
5.07
5.02
4.89
4.84
4.83
%RSD
1.53
1.19
2.27
1.58
1.78
0.94
0.82
2.47
2.18
2.06
Percent
Recovery
98
101
98
98
103
101
100
98
97
97
Surrogate ===> 10iO 10.3 1-.64
Decafluorobyphenyl
(a) Based upon the analysis of eight replicate MTBE sample extracts.
103
551.1-47
-------
TABLE 4.A. PRECISION AND ACCURACY RESULTS USING MTBE3
NH,.C1 PRESERVED FORTIFIED REAGENT HATER ON THE PRIMARY DB-1 COLUMN
ANALYTE
Alachlor
Atrazine
Bromacil
Bromochl oroaceton i tri 1 e
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloropicrin
Chloroform
Cyanazine
Di bromoacetoni tr i 1 e
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1,2-Dibromoethane
Di chl oroacetoni tri 1 e
1 , 1-Di chl oro-2-propanone
Endrin
Endrin Aldehyde
Endrin Ketone
Heptachlor
Heptachlor Epoxide
Hexachlorobenzene
Hexachlorocyclopentadiene
Lindane (g-BHC)
Hethoxychlor
Metolachlor
Hetribuzin
Simazine
Tetrachl oroethyl ene
Tri chl oroaceton i tr i 1 e
Fortified
Cone., fjg/l
0.436
2.520
0.376
0.250
0.250
0.250
0.250
0.250
0.250
0.754
0.250
0.250
0.250
0.250
0.250
0.250
0.062
0.087
0.062
0.063
0.175
0.025
0.075
0.038
0.252
0.878
0.248
2.500
0.250
0.250
Mean Meas.
Cone. , fjg/l
0.515
2.994
0.376
' 0.281
0.276
0.260
0.299
0.285
0.264
0.761
0.276
0.266
0.261
0.274
0.268
0.261
0.073
0.108
0.062
0.059
0.206
0.030
0.074
0.047
0.298
1.056
0.264
2.960
0.263
0.291
%RSD
1.84
1.95
3.32
1.57
1.42
1.62
1.60
2,03.
1.94
1.97
1.89
1.20
1.82
1.89
1.12
0.91
2.65
1.29
0.76
10.29
0.90
3.77
3.22
2.74
3.24
1.00
2.15
2.71
1.93
1.02
Percent
Recovery
118
119
100
113
110
104
120
- 114
105
101
110
106
104
110
107
105
117
123
100
93
118
120
99
125
118
120
107
118
105
116
551.1-48
-------
TABLE 4.A. PRECISION AND ACCURACY RESULTS USING MTBEa (cont'd)
NH^Cl PRESERVED FORTIFIED REAGENT WATER ON THE PRIMARY DB-1 COLUMN
ANALYTE
1,1, 1-Tr i chl oroethane
1,1, 2-Tri chl oroethane
Trichloroethylene
1,2,3-Trichloropropane
1, l,l-Tn'ch1oro-2-propanone.
Trifluralin
Fortified
Cone., //g/L
0.250
0,560
0.250
0.624
0.250
0.088
Mean Meas.
Cone., //g/L
0.291
0.531
0.252
0.595
0.286
0.106
%RSD
3.65
0.85
1.20
0.83
3.72
1.50
Percent
Recovery
116
95
101
95
114
121
Surrogate ===>
Decaf1uorobyphenyl
10.0 - 10.9 2.49 109
s.
(a) Based upon the analysis of eight replicate MTBE sample extracts.
551.1-49
-------
TABLE 4.B. PRECISION AND ACCURACY RESULTS USING MTBE8
Na,SO, PRESERVED FORTIFIED REAGENT WATER ON THE PRIMARY DB-1 COLUMN
ANALYTE
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloral Hydrate
Chloroform
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1,2-Dibromoethane
Tetrachl oroethyl ene
1,1, 1-Tri chl oroethane
Tri chl oroethyl ene
Fortified
Cone., /jg/l
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
0.250
Mean Meas.
Cone. , //g/L
0,270
0.257
0.287
0.258
0.248
0.261
0.258
' 0.243
0.256
0.276
0.246
%RSD
1.77
2.04
5.18
4.12
1.88
1.36
1.26
0.90
1.95
5.72
1,01
Percent
Recovery
108
103
115
103
99
105
103
97
102
110
98
Surrogate -«> 10.0 10.6 3.51 106
Decafluorobyphenyl
(a) Based upon the analysis of eight replicate MTBE sample extracts..
551.1-50
-------
TABLE 5.A. PRECISION AND ACCURACY RESULTS USING MTBEa
NH4C1 PRESERVED FORTIFIED FULVIC ACID ENRICHED REAGENT WATER6 ON THE PRIMARY
DB-1 COLUMN
ANALYTE
Alachlor
Atrazine
Bromacil
Bromochloroacetonitrile
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloropicrin
Chloroform
Cyanazine
Dibromoacetonitrile
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1,2-Dibromoethane
Dichloroacetoni trile
l,l-Dichloro-2-propanone
Eridrin
Endrin Aldehyde
Endrin Ketone
Heptachlor
Heptachlor Epoxide
Hexachlorobenzene
Hexachlorocyclopentadiene
Lindane (g-BHC)
Methoxychlor
Metolachlor
Metribuzin
Simazine
Tetrachl oroethyl ene
Fortified
Cone. , jjq/L
2.18
12.6
1.88
1.00
1.00
1.00
1.00
1.00
1.00
3.77
1.00
1.00
.1.00
1.00
1.00
1.00
0.311
0.437
0.310
0.313
0.875
0.124
0.374
0.188
1.26
4.39
1.24
12.5
1.00
Mean Meas.
Cone., fjq/l
2.38
11.6
1.89
1.11
0.87
0.97
0.88
1.13
1.03
4.02
1.14
0.89
0.93
0.96
1.05
1.03
0.325
0.505
0.319
0.358
0.978
0.139
0.363
0.206
1.41
4.84
1.30
12.0
0.90
%RSD
1.57
2.31
3.33
1.51
1.93
1.50
3.91
2.49
2.47
3.99
1.61
1.78
1.37
1.58
0.98
0.90
3.50
1.99
2.62
5.45
1.28
1.82
3.55
1.79
4.78
1.27
2.08
1.09
4.02
Percent
Recovery
109
92
101
111
87
97
88
113
103
107
114
89
93
96 .
105
103
104
116
103
114
112
112
97
110
112
110
105
96
90
551.1-51
-------
TABLE 5.A. PRECISION AND ACCURACY RESULTS USING MTBE a (cont'd)
NH,C1 PRESERVED FORTIFIED FULVIC ACID ENRICHED REAGENT WATER*5 ON THE PRIMARY
DB-1 COLUMN
ANALYTE
Trichloroacetonitrile
1,1, 1-Tri chl oroethane
1 , 1 , 2-Tri chl oroethane
Trichloroethylene
1,2,3-Trichloropropane
1,1, 1-Tri chl oro-2-propanone
Trifluralin
Fortified
Cone., /yg/L
1.00
1.00
2.80
1.00
3.12
1.00
0.439
Mean Meas.
Cone. , //g/L
1.11
0.96
2.81
0.93
; 2.92
1.10
0.517
%RSD
2.41
3.89
2.89
3.55
0.82
2.05
1.27
Percent
Recovery
111
96
100
93
93
110
118
Surrogate ===> 10.0 10.4 1.84 104
Decaf1uorobyphenyl
(a) Based upon the analysis of eight replicate MTBE sample extracts.
(b) Reagent water fortified at 1.0 mg/L with fulvic acid extracted from
Ohio River water. Sample simulated high TOC matrix.
551.1-52
-------
TABLE 5.B. PRECISION AND ACCURACY RESULTS USING MTBE a
Na2S03 PRESERVED FORTIFIED FULVIC ACID ENRICHED REAGENT WATER ON THE PRIMARY
DB-j.COLUMN
ANALYTE
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloral Hydrate
Chloroform
Dibromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1,2-Dibromoethane
Tetrachl oroethyl ene
1 , 1 , 1-Trichl oroethane
Tri chl oroethyl ene
Fortified
Cone. , fjg/L
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
Mean Meas.
Cone., fjg/L
0.87
0.97
0.88
0.90
0.96
0.88
0.92
0.93
0.90
0.97
0.94
%RSD
1.13
1.28
1-71
0.95
1.51
1.25
0.98
1.01
2.07
1.57
1.62
Percent
Recovery
87
97
88
90
96
88
92
93
90
97
94
Surrogate ===> 10.0 10.6 2.56 106
Decaf1uorobyphenyl
(a) Based upon the analysis of eight replicate MTBE sample extracts.
(b) Reagent water fortified at 1.0 mg/L with fulvic acid extracted from
Ohio River water. Sample simulated high TOC matrix.
551.1-53
-------
TABLE 6.A. PRECISION AND ACCURACY RESULTS USING MTBEa
NH,C1 PRESERVED FORTIFIED GROUND WATER6 ON THE PRIMARY
DB-1 COLUMN
ANALYTE
Alachlor
Atrazine
Bromacil
Bromochl oroacetoni tri 1 e
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloropicrin
Chloroform
Cyanazine
Di bromoacetoni tri 1 e
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1,2-Dibromoethane
Di chl oroacetoni tri 1 e
1 , 1-Di chl oro-2-propanone
Endrin
Endrin Aldehyde
Endrin Ketone
Heptachlor
Heptachlor Epoxide
Hexachlorobenzene
Hexachl orocycl opentadi ene
Lindane (g-BHC)
Methoxychlor
Metolachlor
Metribuzin
Simazine
Tetrachl oroethyl ene
Unfort.
matrix
cone. ,
//g/L
ND c
N.D
ND
ND
1.70
20.1
ND
ND
0.571
ND
ND
6.00
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Fort.
Cone. ,
/vg/L
8,72
50,4
7 , 52
5.00
5.00
5.00
5.00
5.00
5.00
15.1
5.00
5:.00
5,00
5.00
5.00
5.00
1.24
1.75
1.24
1.25
3.50
0 . 50
1.50
0.75
5.04
.17.6
4.96
50.0
5.00
Mean
Meas.
Cone. ,
//g/L
9.01
46.7
6.53
5.74
6.68
24.8
4.99
5.29
5.73
15.4
5.84
11.1
5.04
4.87
5.29
5.01
1.32
1.91
1.22
1.33
3.67
0.509
1.41
0.773
5.60
18.2
4.85
48.3
4.97
%RSD
2.93
3.30
7.81
1.38
2.59
1.61
6.65
3.59
3.68
6.07
1.59
1.89
1.64
1.90
1.52
1.30
4.81
2.36
3.77
4.46
2.92
3.42
3.70
1.91
5.86
3.06
6.15
3.30
6.29
Percent
Recovery
103
93
87
115
100
95
100
106
103
102
117
102
101
97
106
100
106
109
98
106
105
103
94
103
111
103
98
97
99
551.1-54
-------
TABLE 6.A. PRECISION AND ACCURACY RESULTS USING MTBEa (cont'd)
NH4C1 PRESERVED FORTIFIED GROUND WATER6 ON THE PRIMARY
DB-1 COLUMN
ANALYTE
Trichloroacetonitrile
1,1,1-Trichloroethane
1,1, 2-Tri chl oroethane
Trichloroethylene
1,2, 3-Tri chl oropropane
1,1, 1-Trichl oro-2-propanone
Trifluralin
Unfort.
matrix
cone.,
//9/L
ND
1.77
ND
ND
0.340
ND
ND
Fort.
Cone. ,
ywg/L
5.00
5.00
11.2
5.00
12.5
5.00
1.76
Mean
Meas.
Cone.,
//9/L
5.59
6.62
10.4
4.74
12.5
5.21
1.94
%RSD
4.89
4.60
2.98
5.78
3.92
1.58
3.38
Percent
Recovery
112
97
93
95
97
104
110
Surrogate ===> 10.0 10.4 2.25 104
Decaf1uorobyphenyl
(a) Based upon the analysis of eight replicate MTBE sample extracts.
(b) Chlorinated ground water from a water source displaying a hardness of
460 mg/L as CaC03.
(c) ND indicates not detected above the EDL.
551.1-55
-------
TABLE 6.B. PRECISION AND ACCURACY RESULTS USING MTBEa
Na,SO, PRESERVED FORTIFIED GROUND WATER6 ON THE'PRIMARY'DB-1 COLUMN
ANALYTE
Bromodichloromethane
Bromoform
Carbon Tetrachloride
Chloral Hydrate
Chloroform
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1 , 2-Di bromoethane
Tetrachl oroethyl ene
1,1, 1-Tri chl oroethane
Trichl oroethyl ene
Unfort.
matrix
cone. ,
X/9/L
1.77
20.5
ND c
ND
0.600
6.16
ND
ND
ND
1.91
ND
Fort.
Cone. ,
/>g/L
5.00
5.00
5 . 00
2.00
5.00
5.00'
5.00
5.00
5.00
5.00
5.00
Mean
Meas.
Cone.,
//g/L
6.64 :
24.6
4.99
1.84,
5.22
11.0
5.01 .
4,79 :
4.95 '
6.73
4.69
%RSD
1.70
1.63
2.72
1,38
1.89,
1.53
1.19
1.86
2.49
3.18
2.38
Percent
Recovery
97
82
100
92,
92
98
100
96
99;
96
94
Surrogate —=>
Decaf1uorobyphenyl
10.0
10.1
8.71
101
(a) Based upon the analysis of eight replicate MTBE sample extracts.
(b) Chlorinated ground water from a water source displaying a hardness of
460 mg/L as CaC03.
(c) ND indicates Not Detected above the detection limit.
551.1-56
-------
TABLE 7. LABORATORY PERFORMANCE CHECK SOLUTION
parameter
Instrument
Sensitivity
Chromatographic
Performance
Column
Performance
Analyte
Breakdown
Analyte
Lindane
(gamma-BHC)
Hexachl orocycl opentadi ene
Bromodichloromethane
Trichloroethylene
Bromacil
Alachlor
Endrin
Cone.,
jt/g/mL
in MTBE
or pentane
0.000200
0.0200
0.0300
0.0300
0.0830
0.0830
0.0300
Acceptance
Criteria
Detection of
Analyte; = . .-.
Signal to
Noise > 3
PGF between
0.80 and 1.1 5a
Resolution >
0.50b
Resolution >
0.50
%BDC < 20 %
PGF = Peak Gaussian Factor. Calculated using the equation-
1.83 x W(l/2)
PGF = ------ - -------------
b
where W(l/2) is the peak width at half height and W(l/10) is the
peak width at tenth height.
Resolution between the two peaks as defined by the equation:
R = -----
W
where t is the difference in elution times between the two peaks and
W is the average peak width, at the baseline, of the two peaks.
%BD = Percent Breakdown. Endrin breakdown calculated using the
equation.
(AREA Endrin Ketone + AREA Endrin Aldehyde)
= x
(AREA Endrin Ketone + AREA Endrin Aldehyde + AREA Endrin)
Note: If laboratory EDL's differ from those listed in this method,
concentrations of the LPC standard must be adjusted to be
compatible with the laboratory EDL's.
551.1-57
-------
TABLE 8. METHOD DETECTION LIMIT USING PENTANE
NH4C1 PRESERVED REAGENT WATER ON PRIMARY DB-1 COLUMN
ANALYTE
Alachlor
Atrazine
Bromacil
Bromochl oroaceton i tri 1 e
Bromodi chl oromethane
Bromoform
Carbon Tetrachloride
Chloropicrin
Chloroform
Cyanazine
Di bromoacetoni tri 1 e
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1,2-Dibromomethane
Di chloroacetoni tri 1 e
i;i-Dichloro-2-propanone
Endrin
Endrin Aldehyde
Endrin Ketone
Heptachlor
Heptachlor Epoxide
Hexachlorobenzene
Hexachl oropentadi ene
Lindane (g-BHC)
Methoxychlor
Metol achl or
Metribuzin
Simazine
Tetrachl oroethyl ene
Fort.
Cone.
A/g/L
0.109
0.633
0.094
0.040
0.040
0,
0,
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.040
.040
.040
.040
.189
.040
.040
.040
.040
.040
.040
.016
.022
.016
.016
.044
.0062
.040
.0094
.063
.219
.062
.625
.040
Observ.b
Cone.
A/g/L
0.095a
0.663
0.058
0.
,047
0.054
0,033
0,
.060
0,045
0,
0.
0
0
0
0
0
0
0
0
0
0.
0
0
0
0
0
0
0
0
0
,110
170a
,046
,050
.053
.053
.037
.042
.019
.023
•.014
Olla
.045
,008
.022
.006
.069
.267
.076
.662
.052
Avg.
%Rec.
87
105
62
118
135
83
150
113
275
90
115
125
133
133
93
105
119
105
88
69
102
129
55
64
110
122
123
106
130
%RSD
5.37
5.00
21.44
3.61
42.05
20.60
27.76
4.25
24.36
13.37
3
5
5
19
20
4
4
5
9
18
5
9
24
91
12
10
18
9
5
.84
.48
.39
.85
.09
.86
.69
.52 .
. 50
.14
.02
.56
.42
.20
.76
.35
.15
.42
.33
MDLC
A/g/L
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
015
099
037
005
068
020
050
006
080
068
005
008
009
032
022
006
,003
0.004
0.004
0.006
0.007
0.002
0.016
0.017
0
0
0
0
0
.026
.083
.041
.187
.008
EDLd
A/g/L
0.050
0.390
0.330
0.026
0.068
0.035
0.050
0.023
0.080
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.200
.030
.026
.017
.032
.042
.022
.016
.022
.020
.009
.0*16
.002
.016
.017
.066
.172
.041
.420
.016
551.1-58
-------
TABLE 8. METHOD DETECTION LIMIT USING PENTANE (cont'd)
NH4C1 PRESERVED REAGENT WATER ON PRIMARY DB-1 COLUMN
ANALYTE
Tri chl oroaceton itr i 1 e
1,1,1-Trichloroethane
1,1, 2-Trl chl oroethane
Trichloroethylene
1,2,3-Trichloropropane
1, 1, l-Trichloro-2-propanone
Trifluralin
Fort.
Cone.
//g/L
0.040
0.040
0.140
0.040
0.156
0.040
0.040
Observ.b
Cone.
//g/L
0.048
0.058
0.141
0.064
0.151
0.045
0.021
Avg.
%Rec.'
120
145
101
160
97
113
53
%RSD
2.79
4.26
4.01
21.80
3.54
3.65
19.28
MDLC
//g/L
0.004
0.007
0.017
0.042
0.016
0.005
0.012
EDLd
//g/L
0.014
0.017
0.052
0.042
0.116
0.024
0.012
Surrogate ===>
Decaf1uorobyphenyl
10.0
11.2 112
3.98
(a) Quantitated from confirmation column due to.baseline interference on
primary column.
(b) Based upon the analysis of eight replicate pentane sample extracts.
(c) MDL designates the statistically derived MDL and is calculated by '
multiplying the standard deviation of the eight replicates by the
student's t-value (2.998) appropriate for a 99% confidence level and a
standard deviation estimate with n-1 degrees of freedom.
(d) Estimated Detection Limit (EDL) — Defined as either the MDL or a level
of compound in a sample yielding a peak in the final extract with a
signal to noise (S/N) ratio of approximately 5, whichever is greater
551.1-59
-------
TABLE 9. PRECISION AND ACCURACY RESULTS3
USING PENTANE
NH4C1 PRESERVED FORTIFIED REAGENT HATER ON THE PRIMARY DB-1
COLUMN
ANALYTE
Alachlor
Atrazine
Bromacil
Bromochl oroacetoni tri 1 e
Bromodichloromethane
Bromoform
Carbon Tetrachloride
Chloropicrin
Chloroform
Cyanazine
Dibromoacetonitrile
Di bromochl oromethane
1 , 2-Di bromo-3-chl oropropane
1,2-Dibromoethane
Dichloroacetonitrile
l,l-Dichloro-2-propanone
Endrin
Endrin Aldehyde
Endrin Ketone
Heptachlor Epoxide
Heptachlor
Hexachlorobenzene
Hexachl orocycl opentadi ene
Lindane (g-BHC)
Methoxychlor
Metolachlor
Hetribuzin
Simazine
Tetrachl oroethyl ene
Fortified
Cone. , jjg/L
2.18
12.6
1.88
5.00
5.00 :
5.00
5.00
5.00
5.00
3.77
5.00
5.00
5.00
5.00
5.00
5.00
0.311
0.437
0.310':
0.875
0.313b'
0.124
0.374
0.188.
1.26
4.39 :
1.24
12.5 '
5.00 [
551.1-60;
Mean Meas.
Cone. , //g/L
1.98 b
12.0
1.74
4.63
4.46
4.81
4.61
4.51
4.95
4.00 b
4.80
4.23
4.73
4.69
4.73
4.78
0.312
0.443
0.311
0.866
0.30
0.123
0.384
0.176
1.28
4.42
1.34
12.5
4.46
%RSD
5.09
3.09
2.95
3.18
4.07
2.76
4.14
2.46
2.90
2.59
2.87
3.38
3.00
2.54
3.39
3.04
2.61
2.29
2.10
2.11
3.47
2.51
3.30
10.23
3.03
2.36
2.13
2.20
3.67
Percent
Recovery
91
95
93
93
89
96
92
90
99
106
96
85
95
94
95
96
100
101
100
99
97
99
103
94
102
101
108
100
89
-------
TABLE 9. PRECISION AND ACCURACY RESULTS3 (cont'd)
USING PENTANE
NH4C1 PRESERVED FORTIFIED REAGENT WATER ON THE PRIMARY DB-1 COLUMN
ANALYTE
Trichloroacetonitrile
1, 1 , 1-Trichloroethane
1, 1,2-Trichloroethane
Trichloroethylene
1,2,3-Trichloropropane
1 , 1 , 1-Tri chl oro-2-propanone
Trifluralin
Surrogate===>
Decaf luorobyphenyl
Fortified
Cone., fjg/l
5.00
5.00
2.80
5.00
3.12
5.00
0.439
10.0
Mean Meas.
Cone., jjq/l
5.07
4.70
2.62
4.84
3.13
4.88
0.446
10.7
%RSD
4.02
3.39
2.03
2.98
1.76
2.80
2.74
1.88
Percent
Recovery
101
94
93
97
100
98
102
107
(a) Based upon the analysis of eight replicate pentane sample extracts.
(b) Quantitated from confirmation column due to baseline interference
on primary column.
551.1-61
-------
TABLE 10. ANALYTE PEAK IDENTIFICATION, RETENTION TIMES,
CONCENTRATIONS AND CONDITIONS USING MTBE FOR FIGURE 1
NH,C1 PRESERVED FORTIFIED REAGENT WATER ON THE
PRIMARY DB-1 COLUMN
PEAK
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Retention
Time3
ANALYTE minutes
Chloroform
1,1,1-Trichloroethane
Carbon Tetrachloride
Trichloroacetonitrile ;
Dichloroacetonitrile
Bromodi chl oromethane
Trichloroethylene
Chloral Hydrate
1 , 1-Di chl oro-2-Propanone
1 , 1 , 2-Tri chl oroethane
Chloropicrin
Di bromochl oromethane
Bromochl oroacetoni tri 1 e
1,2-Dibromoethane (EDB)
Tetrachl oroethyl ene
1 , 1 , 1-Tri chl oropropanone
Bromoform
Di bromoacetoni tri 1 e
1,2,3-Trichloropropane
1 , 2-Di bromo-3-chl oropropane (DBCP)
Surrogate: Decaf luorobiphenyl
Hexachl orocycl opentadi ene
Trifluralin
Simazine
Atrazine
Hexachl orobenzene
Lindane (gamma-BHC)
Metribuzin
7.04
8.64.
9.94
10.39
12.01
12.42
12.61
13.41
14.96
19.91
23.10
23.69
24.03
24.56
26.24
27.55
29.17
29.42
30.40
35.28
36.35
40.33
45.17
46.27
46.55
47.39
47.95
50.25
Cone.
' M/l
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
44.8
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
50.0
5.00
10.0
28.0
7.04
200
200
1.98
30.1
19.9
551.1-6?.
-------
TABLE 10. ANALYTE PEAK IDENTIFICATION, RETENTION TIMES,
CONCENTRATIONS AND CONDITIONS USING MTBE FOR FIGURE 1 (cont'd)
NH4C1 PRESERVED FORTIFIED REAGENT WATER ON THE
PRIMARY DB-1 COLUMN
PEAK
#
29
30
31
32
33
34
35
36
37
38
NOTE:
ANALYTE
Bromacil
Alachlor
Cyanazine
Heptachlor
Metolachlor
Heptachlor Epoxide
Endrin
Endrin Aldehyde
Endrin Ketone
Methoxychlor
Bromofiuorobenzene (ret.
standard was not included
Retention
Time3
minutes
52.09
52.25
53.43
53.72
55.44
58.42
64.15
65.46
72.33
73.53
time 31.00 rri'in.) as the
in this chromatogram.
Cone.
ywg/L
30.1
34.9
60.4
5.00
70.0
14.0
5.00
7.00
4.96
20.1
internal
(a) Column A -
0.25 mm ID x 30 m fused silica capillary with chemically
bonded methyl polysiloxane phase (J&W, DB-1, 1.0 urn film
thickness or equivalent). The linear velocity of the
helium carrier is established at 25 cm/sec at 35°C.
The column oven is temperature programmed as follows:
[1] HOLD at 35°C for 22 min
[2] INCREASE to 145°C at 10°C/min and hold at 145°C for 2 min.
[3] INCREASE to 225°C at 20°C/min and hold at 225°C for 15
min.
[4] INCREASE to 260°C at 10°C/min and hold at 260°C for 30
min. or until all expected compounds have eluted.
Injector temperature: 200°C
Detector temperature: 290°C
551.1-63
-------
FIGURE 1. FORTIFIED REAGENT WATER EXTRACT USING MTBE ON PRIMARY DB-1 COLUMN
15
12
_A
17
1« "18
"
H
"
.... -._! _ , _ . - . - . - 1 - , - . - . - . - 1
IB 15
2i 25
MINUTES
38
3*
21
23
25
'(
bUL
33
li
i .... _.i
35 48
45 Si 55
69
65
MINUTES
78 75 60 85
551.1-64
-------
TABLE 11. ANALYTE PEAK IDENTIFICATION, RETENTION TIMES,
CONCENTRATIONS AND CONDITIONS USING MTBE FOR FIGURE 2
NH4C1 PRESERVED FORTIFIED REAGENT WATER ON THE
CONFIRMATION RtX-1301
PEAK
.#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19 .
20
21
22
23
24
25
26
27
ANALYTE
Chloroform
1,1,1-Trichloroethane
Carbon Tetrachloride
Trichloroacetonitrile
Trichloroethylene
Bromodichloromethane
1 , l-Dichloro-2-Propanone
Chloropicrin
Tetrachl oroethyl ene
1 , 1 , 2-Tri chl oroethane
Dichloroacetonitrile
Di bromochl oromethane
1,2-Dibromoethane (EDB)
1,1, 1-Tri chl oropropancne
Bromochl oroacetoni tri 1 e
Bromoform
1 , 2 , 3-Tri chl oropropane
Dibromoacetonitrile
1 , 2-Di bromo-3-chl oropropane (DBCP)
Surrogate: Decaf luorobiphenyl
Hexachl orocycl opentadi ene
Trifluralin
Hexachl orobenzene
Atrazine/Simazine
Lindane (gamma-BHC)
Heptachlor
Metribuzin
Retention
Time3
minutes
7.73
7.99
8.36
10.35
11.96
15.28
20.50
23.69
24.77
25.01
25.21
26.32
26.46
28.47
29.86
30.36
31.73
32.77
36.11
36.28
39.53
45.43
46.47
48.56
49.68
53.15
53.92
Cone.
//g/L
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
44.8
5.00
5.00
5.00
5.00.
5.00
5.00
50.0
5.00
5.00
10.0
28.0
7.04
1.98
400
30.1
5.00
19.9
551.1-65
-------
TABLE 11. ANALYTE PEAK IDENTIFICATION, RETENTION TIMES,
CONCENTRATIONS AND CONDITIONS USING MTBE FOR FIGURE 2 (cont'd)
NH,C1 PRESERVED FORTIFIED REAGENT WATER ON THE
CONFIRMATION RtX-1301
Retention
Time3 Cone.
ANALYTE minutes /vg/L
28 Alachlor 54.38 34.9
29 Metolachlor 57.07 70.0
30 Heptachlor Epoxide 59.05 14.0
31 Bromacil 59.60 30.1
32 Cyanazine - 59.89 60.4
33 Endrin 65.24 5.00
34 Endrin Aldehyde 71.56 7.00
35 Methoxychlor 76.73 20.1
36 Endrj n Ketone 81.28 4.96
"NOTE': BTbmoTTuorobenz'erie (ret. time 31.30 min.) as the internal
standard was not included in this chromatogram.
(a) Column B - 0.25 mm ID x 30 m with chemically bonded 6 %
cyanopropylphenyl / 94 % dimethyl polysiloxane phase
(Restek, Rtx-1301, 1.0 fim film thickness or equivalent).
The linear velocity of the helium carrier gas is
established at 25 cm/sec at 35°C.
The column oven is temperature programmed as follows:
The column oven is temperature programmed as follows:
[1] HOLD at 35°C for 22 min
[2] INCREASE to 145°C at lp°C/min and hold at 145°C for 2 min
[3] INCREASE to 225°C at 20°C/min and hold at 225°C for 15 min
[4] INCREASE to 260°C at 10°C/min and hold at 260°C for 30
min. or until all expected compounds have eluted.
Injector temperature: 200°t
Detector temperature: 290°C
551.1-66
-------
FIGURE 2. FORTIFIED REAGENT WATER EXTRACT USING MTBE ON CONFIRMATION Rtx-1301
COLUMN
I 8
12
U
,13
15
16
17
U
21
-J—.—i—i—i—I—i—i—.—i—i—, 1—.—i—i—,—, , i, .... i
5 10 15
2B 25
MINUTES
3B 35
38
27
22
29
28
32
33
A
31
35
-1 i ' 1 1 1 . . 1 . 1 1 L : , 1 , , ,__, I , . . . I
45 50 55
60 65
MINUTES
78 75 81 85
551.1-67
-------
TABLE 12. ANALYTE PEAK IDENTIFICATION, RETENTION TIMES, CONCENTRATIONS
AND CONDITIONS USING PENTANE FOR FIGURE 3
NH4C1 PRESERVED FORTIFIED REAGENT WATER ON THE
PRIMARY DB-1 COLUMN
Retention
PEAK Time3
-# ANALYTE minutes
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
Chloroform
1 , 1 , 1-Tri chl oroethane
Carbon Tetrachloride
Trichloroacetonitrile
Di chl oroaceton i tri 1 e
Bromodi chl oromethane
Tri chl oroethyl ene
1 , 1-Di chl oro-2-Propanone
1 , 1 , 2-Tri chl oroethane
Chloropicrin
Di bromochl oromethane
Bromochl oroacetoni tri le
1,2-Dibromoethane (EDB)
Tetrachl oroethyl ene
1 , 1 , 1-Tri chl oropropanone
Bromoform
Di bromoacetoni tri 1 e
1,2, 3-Tri chl oropropane
Internal Standard: Bromofluorobenzene
1 , 2-Di bromo-3-chl oropropane (DBCP)
Surrogate: Decaf luorobiphenyl
Hexachl orocycl opentadi ene
TrifluraTin
Simazine
Atrazine
Hexachl orobenzene
Lindane (gamma-BHC)
8.41
10.26
11.56
12.03
13.53
13.73
13.89
15.60
18.57
20.49
21.03
21.25
22.03
24.75
27.94
30.97
31.45
32.82
33.60
38.34
39.48
43.92
49.04
50.08
50.37
51.11
51.66
Cone.
fJ<3/l
5.00
5.00
5.00
5.00
5.00
5.00
5.00
5.00
44.8
5.00
5.00
5.00
5.00
5.00
5.00
5.00
. 5.00
50.0
1.00 /yg/mL in
pentane extract
5.00
10.0
28.0
7.04
200
200
1.98
30.1
551.1-68
-------
TABLE 12. ANALYTE PEAK IDENTIFICATION, RETENTION TIMES, CONCENTRATIONS
AND CONDITIONS USING PENTANE FOR FIGURE 3 (cont'd)
NH4C1 PRESERVED FORTIFIED REAGENT WATER ON THE .
PRIMARY DB-1 COLUMN
PEAK
#
28
29
30
31
32
33
34
35
36
37
38
(a) Col
ANALYTE
Metribuzin
Bromacil
Alachlor
Cyanazine
Heptachlor
Metolachlor
Heptachlor Epoxide
Endrin
Endrin Aldehyde
Endrin Ketone
Methoxychlor
umn A - 0.25 mm
Retention
Time3
minutes
53.95
55.72
55.87
57.04
57.21
59.13
62.50
68.00
69.25
75.74
76.98
ID x 30 m fused silica capillary
Cone.
0g/L
19.9
30.1
34.9
60.4
5.00
70.0
14.0
5.00
7.00
4.96
20.1
r with chemically
bonded methyl polysiloxane .phase (J&W, DB-1, 1.0 fim film
thickness or equivalent). The linear velocity of the
helium carrier is established at 25 cm/sec at 35°C.
The column oven is temperature programmed as follows:
[1] HOLD at 15°C for 0 min
[2] INCREASE to 50°C at 2°C/min and hold at 50°C for 10 min
[3] INCREASE to 225°C at 10°C/min and hold at 225°C for 15 min
[4] INCREASE to 260°C at 10°C/min and hold at 260°C for 30
min. or until all expected compounds have eluted.
Injector temperature: 200°C
Detector temperature: 290°C
551.1-69
-------
FIGURE 3.
COLUMN
FORTIFIED REAGENT WATER EXTRACT USING PENTANE ON PRIMARY DB-1
U
21
5 J
IB
13
15
17 19
21
1 , . 1 1
11 15
2B 25
MINUTES
30 35 M
28
23
KM
Nl (27
31
3i 32
V 33
36
35
38
37
45 5B 55
65 70
MINUTES
75 80 15
551.1-70
-------
I
METHOD.552.2 DETERMINATION OF HALOACETIC ACIDS AND DALAPON IN DRINKING WATER
BY LIQUID-LIQUID EXTRACTION, DERIVATIZATION AND GAS
CHROMATOGRAPHY WITH ELECTRON CAPTURE DETECTION.
Revision 1.0
J.W. Hodgeson (USEPA), J. Collins and R.E. Barth (Technology Applications
Inc.) - Method 552.0, (1990)
J.W. Hodgeson (USEPA), D. Becker (Technology Applications Inc.) -? Method
552.1, (1992)
D.J. Munch, J.W. Munch (USEPA) and A.M. Pawlecki (International Consultants,
Inc.), Method 552.2, Rev. 1.0, (1995)
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
552.2-1
-------
METHOD 552.2 DETERMINATION OF HALOACETIC ACIDS AND DALAPON
IN DRINKING WATER BY LIQUID-LIQUID EXTRACTION, DERIVATIZATION
AND GAS CHROMATOGRAPHY WITH ELECTRON CAPTURE DETECTION
1. SCOPE AND APPLICATION
1.1 This is a gas chromatographic (GC) method (1-8) applicable to the
determination of the listed halogenated acetic acids in drinking
water, ground water, raw source water and water at any intermediate
treatment stage. In addition, the chlorinated herbicide, Dalapon,
may be determined using this method.
Chemical Abstract Services
Analvte Registry Number
Bromochloroacetic Acid (BCAA) 5589-96-3
Bromodichloroacetic Acid (BDCAA) 7113-314-7
Chlorodibromoacetic Acid (CDBAA) 5278-95-5
Dalapon 75-99-0
Dibromoacetic Acid (DBAA) 631-64-1
Dichloroacetic Acid (DCAA) 79-43-6
Monobromoacetic Acid (MBAA) 79-08-3
Monochl.oroacetic Acid (MCAA) 79-11-8
Tribromoacetic Acid (TBAA) 75-96-7
Trichloroacetic Acid (TCAA) 76-03-9
1.2 This method is applicable to the determination of the target
analytes over the concentration ranges typically found in drinking
water (1,2,4). Experimentally determined method detection limits
(MDLs) for the above listed analytes are provided in Table 2.
Actual MDLs may vary according to the particular matrix analyzed and
the specific instrumentation employed. The haloacetic acids are
observed ubiquitously in chlorinated drinking water supplies at
concentrations ranging from <1 to >50 M9/L-
1.3 This method is designed for analysts skilled in liquid-liquid
extractions, derivatization procedures and the .use of GC and
interpretation of gas chromatograms. Each analyst must demonstrate
the ability to generate acceptable results with this method using
the procedure described in Section 9.3.
1.4 When this method is used for the analyses of waters from unfamiliar
sources, it is strongly recommended that analyte identifications be
confirmed by GC using a dissimilar column or by GC/MS if
concentrations are sufficient.
2. SUMMARY OF METHOD
2.1 A 40-mL volume of sample is adjusted to pH <0.5 and extracted with
4-mL of methyl-tert-butyl-ether (MTBE). The haloacetic acids that
have been partitioned into the organic phase are then converted to
552.2-2
-------
their methyl esters by the addition of acidic methanol followed by
slight heating. The acidic extract is neutralized by a back-
extraction with a saturated solution of sodium bicarbonate and the
target analytes are identified and measured by capillary column gas
chromatography using an electron capture detector (GC/ECD).
Analytes are quantitated using procedural standard calibration.
3. DEFINITIONS
3.1 INTERNAL STANDARD (IS) — A pure analyte(s) added to a sample,
extract, or standard solution in known amount(s) and used to measure
the relative responses of other method analytes and surrogates that
are components of the same sample or solution. The internal
standard must be an analyte that is not a sample component.
3.2 SURROGATE ANALYTE (SA) — A pure analyte(s), which is extremely
unlikely to be found in any sample, and which is added to a sample
aliquot in known amount(s).before extraction or other processing and
is measured with the same procedures used to measure other sample
components. The purpose of the SA is to monitor method performance
with each sample. <
3.3 LABORATORY DUPLICATES (LD1 AND LD2) — Two aliquots of the same
sample designated as such in the laboratory. Each aliquot is
extracted, derivatized and analyzed separately with identical
procedures. Analyses of LD1 and LD2 indicate the precision
associated with laboratory procedures, but not with sample
collection, preservation, or storage procedures.
3.4 FIELD DUPLICATES (FD1 AND FD2J — Two separate samples collected at
the same time and place under identical circumstances and treated
exactly the same throughout field and laboratory procedures.
Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation and storage, as well as with
laboratory procedures.
3.5 LABORATORY REAGENT BLANK (LRB) — An aliquot of reagent water or
other blank matrix that are treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents, internal
standards, and surrogates that are used with other samples. The LRB
is used to determine if method analytes or other interferences are
present in the laboratory environment, the reagents, or the
apparatus.
3.6 FIELD REAGENT BLANK (FRB) — An aliquot of reagent water or other
blank matrix that is placed in a sample container in the laboratory
and treated as a sample in all respects, including shipment to the
sampling site, exposure to sampling site conditions, storage,
preservation and all analytical procedures. The purpose of the FRB
is to determine if method analytes or other interferences are
present in the field environment.
552.2-3
-------
3.7 LABORATORY FORTIFIED BLANK (LFB) ~ An aliquot of reagent water or
other blank matrix to which known quantities of the method analytes
are added'in the laboratory. The LFB is analyzed exactly like a
sample, and its purpose is to determine whether,the methodology is
in control, and whether the laboratory is capable of making accurate
and precise measurements.
3.8 LABORATORY FORTIFIED SAMPLE MATRIX (LFM) — An aliquot of an
environmental sample to which known quantities of the method
analytes are added in the laboratory. The LFM is analyzed exactly
like -a sample, and its purpose is to determine whether the sample
matrix contributes bias to the analytical results. The background
concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the LFM
corrected for background concentrations.
3.9 STOCK STANDARD SOLUTION (SSS) — A concentrated solution containing
one or more method analytes prepared in the laboratory using assayed
reference materials or purchased from a reputable commercial source.
3.10 PRIMARY DILUTION STANDARD SOLUTION (PDS) — A solution of several
analytes prepared in the laboratory from stock standard solutions
and diluted as needed to prepare calibration solutions and other
needed analyte solutions.
3.11 CALIBRATION STANDARD (CAL) — A solution prepared from the primary
dilution standard solution and stock standard solutions of the
internal standards and surrogate analytes. The CAL solutions are
used to calibrate the instrument response with respect to analyte
concentration.
3.12 QUALITY CONTROL SAMPLE (QCS) — A solution of method analytes of
known concentration which is used to fortify an aliquot of reagent
water or sample matrix. The QCS is obtained from a source external
to the laboratory and different from the source of calibration
standards. It is used to check laboratory performance with
externally prepared test material si
3.13 LABORATORY PERFORMANCE CHECK SOLUTION (LPC) — A solution of
selected method analytes used to evaluate the performance of the
instrumental system with respect to a defined set of method
criteria.
3.14 METHOD DETECTION LIMIT (MDL) — The minimum concentration of an
analyte that can be identified, measured and reported with 99%
confidence that the analyte concentration is greater than zero.
3.15 MATERIAL SAFETY DATA SHEET (MSDS) — Written information provided by
vendors concerning a chemical's toxicity, health hazards, physical
properties, fire and reactivity da;ta including storage, spill, and
handling precautions.
552.2-4
-------
3.16 ESTIMATED DETECTION LIMIT (EDL) -- Defined as either the MDL or a
level of a compound in a sample yielding a peak in the final extract
with a signal to noise (S/N) ratio of approximately 5, whichever is
greater.
3.17 PROCEDURAL STANDARD CALIBRATION — A calibration method where
aqueous calibration standards are prepared and processed (e.g.
purged, extracted and/or derivatized) in exactly the same manner as
a sample. All steps in the process from addition of sampling
preservatives through instrumental analyses are included in the
calibration. Using procedural standard calibration compensates for
any inefficiencies in the processing procedure.
3.18 CONTINUING CALIBRATION CHECK (CCC) -- A calibration standard con-
taining one or more method analytes, which is analyzed periodically
to verify the accuracy of the existing calibration curves or re-
sponse factors for those analytes.
4. INTERFERENCES
4.1
Method interferences may be caused by contaminants in solvents,
reagents, glassware and other.sample processing apparatus that lead
to discrete artifacts or elevated baselines in chromatograms. All
reagents and apparatus must be routinely demonstrated to be free
from interferences under the conditions of the analysis by analyzing
laboratory reagent blanks as described in Section 9.5. Subtracting
blank values from sample results is not permitted.
4.1.1 Glassware must be scrupulously cleaned. Clean all glassware
as soon as possible after use by thoroughly rinsing with the
last solvent used in it. Follow by washing with hot water
and detergent and thorough rinsing with tap water and reagent
water. Drain and heat in an oven or muffle furnace at 400°C
for 1 hr. Do not heat volumetric ware but instead rinse
three times with HPLC grade or better acetone. Thorough
rinsing with reagent grade acetone may be substituted for the
heating provided method blank analysis confirms no background
interferant contamination is present. Thermally stable
materials such as PCBs may not be eliminated by these treat-
ments. After drying and cooling, store'glassware in a clean
environment free of all potential contamination. To prevent
any accumulation of dust or other contaminants, store glass-
ware inverted or capped with aluminum foil.
4.1.2 The use of high purity reagents and solvents helps to mini-
mize interference problems. Each new bottle of solvent
should be analyzed before use. An interference free solvent
is a solvent containing no peaks yielding data at > MDL
(Table 2) and at the retention times of the analytes of
interest. Purification of solvents by distillation in all-
glass systems may be required.
552.2-5
-------
4.2 Interfering contamination may occur when a sample containing low
concentrations of analytes is analyzed immediately following a
sample containing relatively high concentrations of analytes.
Routine between-sample rinsing of the sample syringe and associated
equipment with MTBE can minimize ;sample cross-contamination. After-
analysis of a sample containing high concentrations of analytes, one
or more injections of MTBE should be made to ensure that accurate
values are obtained for the next sample.
4.3 Matrix interferences may be caused by contaminants that are coex-
tracted from the sample. The extent of matrix interferences will
vary considerably from source to ;source, depending upon the water
sampled. Analyte identifications should be confirmed using the
confirmation column specified in Table 1 or by GC/MS if the concen-
trations are sufficient.
4.4 Bromochloroacetic acid coelutes with an interferant on the DB-1701
confirmation column. The interferant has been tentatively identi-
fied as dimethyl sulfide. However, because of the difference in
peak shapes, the peak for the ester of BCAA tends to "ride on" the .
interferant peak and quantitative confirmation can be performed by
manual integration that includes only the peak area of the target
ester.
4.5 Methylation using acidic methanol results in a partial decarboxyl-
ation of tribromoacetic acid (8). Therefore a substantial peak for
' bromoform will be observed in the chromatograms. Its elution does
not, however, interfere with any other analytes. Furthermore, this
demonstrates the need for procedural standards to establish the
calibration curve by which unknov/n samples are quantitated.
5. SAFETY
5.1 The toxicity or carcinogenicity of each reagent used in this method
has not been precisely defined; however, each chemical compound must
be treated as a potential health hazard. From this viewpoint,
exposure to these chemicals must be minimized. The laboratory is
responsible for maintaining a current awareness file of OSHA regula-
tions regarding the safe handling of the chemicals specified in this
method. A reference file of material safety data sheets should also
be made available to all personnel involved in the chemical analy-
sis. Additional references to laboratory safety are available and
have been identified (9-11) for the information of the analyst.
5.2 The toxicity of the extraction solvent, MTBE, has not been well
defined. Susceptible individuals may experience adverse affects
upon skin contact or inhalation of vapors. Therefore protective •
clothing and gloves should be used and MTBE should be used only in a
chemical fume hood or glove box. The same precaution applies to
pure standard materials.
552.2-6
-------
6. APPARATUS AND EQUIPMENT
6.1 SAMPLE CONTAINERS — Amber glass bottles, approximately 50 ml
, fitted with Teflon-lined screw caps. '
6.2 EXTRACTION VIALS— 60 ml clear glass vials with teflon-lined screw
caps.
6.3 VIALS — Autosampler, 2.0 mL vials with screw or crimp cap and a
teflon-faced seal. ,, -.
6.4 STANDARD SOLUTION STORAGE CONTAINERS - .-10-20-ml amber glass vials
with teflon lined-screw caps. .
6.5 GRADUATED CONICAL CENTRIFUGE TUBES WITH TEFLON-LINED SCREW CAPS -
15-mL with graduated 1 mL markings.
6.6 BLOCK HEATER (or SAND BATH) - Capable of holding screw cap conical
centrifuge .tubes in Section 6.4.
6.7 PASTEUR PIPETS — Glass, disposable. .
6.8 PIPETS — 2.0 mL and 4.0 mL, type A, TD, glass.
6.9- VOLUMETRIC FLASKS — 5 ml, 10 mL.
6-10 MICRO SYRINGES - 10 /tl_, 25 fil, 50 /iL, 100 0L, 250 fil, 500V and
6.11 BALANCE — analytical, capable of weighing to 0.0001 g.
6.12 GAS CHROMATOGRAPH — Analytical system complete with gas chromato-
graph equipped for electron capture detection, split/splitless
capillary or direct injection, temperature programming, differential
flow control, and with all required accessories including syringes
analytical columns, gases and strip-chart recorder. A data system'
is recommended for measuring peak areas. An autoinjector is recom-
. mended for improved precision of analyses. The gases flowing
through the electron capture detector should be vented through the
laboratory fume hood system.
6.13 PRIMARY GC COLUMN - DB-5.625 [fused silica capillary with chemical-
ly bonded (5% phenyl)-methylpolysiloxane)] or equivalent bonded
fused silica column, 30m x 0.25mm ID, 0.25 /im film thickness. '
6.14 CONFIRMATION GC COLUMN -- DB-1701 [fused silica capillary with
chemically bonded (14% cyanopropylphenyl)-methylpolysiloxane)l or
equivalent bonded, fused silica column, 30 m x 0.25 mm ID, 0.25 urn
film thickness.
552.2-7
-------
7. REAGENTS AND STANDARDS
7.1 REAGENT WATER — Reagent water is defined as a water in which an
interference is not observed > to the MDL of each analyte of inter-
est.
7.1.1 A Millipore Super-Q water system or its equivalent may be
used to generate deionized reagent water. Distilled water
that has been passed through granular charcoal may also be
suitable.
7.1.2 Reagent water is monitored through analysis of the labora-
tory reagent blank (Section 9.5).
7.2 SOLVENTS
7.2.1 METHYL-TERT-BUTYL ETHER — High purity, demonstrated to be
free of analytes and interferences, redistilled in glass if
necessary.
7.2.2 METHANOL — High purity, demonstrated to be free of
analytes and interferences.
7.2.3 ACETONE — High purity, demonstrated to be free of analytes
and interferences.
7.3 REAGENTS
7.3.1 SODIUM SULFATE, Na2S04 — (ACS) granular* anhydrous. If
interferences are observedj.it may be necessary to heat the
sodium sulfate in a shallow tray at 400°C for up to 4 hr. to
remove phthalates and other interfering organic substances.
Alternatively, it can be extracted with methylene chloride in
a Soxhlet apparatus for 48 hr. Store in a capped glass
bottle rather than a plastic container.
7.3.2 COPPER II SULFATE PENTAHYDRATE, CuS04'5H20 -- ACS re-
agent grade.
7.3.3 SODIUM BICARBONATE, NaHC03 -- ACS reagent grade.
7.3.4 AMMONIUM CHLORIDE, NH4C1 — ACS reagent grade, used to
convert free chlorine to monochloramine. Although this
is not the traditional dechlorination mechanism, ammoni-
um chloride is categorized as a dechlorinating agent in
this method.
7.4 SOLUTIONS
7.4.1 10% H2S04/METHANOL SOLUTION -- Use caution when prepar-
ing sulfuric acid solutions. To prepare a 10% solution,
add 5 mL sulfuric acid dropwise (due to heat evolution)
552.2-8
-------
7.4.2
to 20-30 mL methanol contained in a 50.0 mL volumetric
flask that has been placed in a cooling bath. Then
dilute to the 50.0 ml mark with methanol.
SATURATED SODIUM BICARBONATE SOLUTION — Add sodium
bicarbonate to a volume of water, mixing periodically
until the solution has reached saturation.
7.5 STANDARDS
7.5.1
1,2,3-TRICHLOROPROPANE, 99+% — For use as the internal
standard. Prepare an internal standard stock standard solu-
tion of 1,2,3-trichloropropane in MTBE at a concentration of
approximately 1 mg/mL. From this stock standard solution,
prepare a primary dilution standard in MTBE at a concentra-
tion of 25
7.5.2 2,3-DIBROMOPROPIONIC ACID, 99+% — For use as a surrogate
compound. Prepare a surrogate stock standard solution of
2,3-dibromopropionic acid in MTBE at a concentration of
approximately 1 mg/mL. From this stock standard solution,
prepare a primary dilution standard in MTBE at a concentra-
tion of 10 /ig/mL.
7.5.3 STOCK STANDARD SOLUTION (SSS) .
Prepare separate stock standard solutions for each analyte of
interest at a concentration of 1-5 mg/mL in MTBE. Method
analytes may be obtained as neat materials or ampulized
solutions (> 99% purity) from a number of commercial suppli-
ers. These stock standard solutions shcjld be stored at -
10°C and protected from light. They are stable for at least
one month but should be checked frequently for signs of
evaporation.
7.5.3.1. For analytes which are solids in their pure form,
prepare stock standard solutions by accurately
weighing approximately 0.01 to 0.05 grams of pure
material in a 10.0 mL volumetric flask. Dilute to
volume with MTBE. When a compound purity is assayed
to be 96% or greater, the weight can be used without
correction to calculate the concentration of the
stock standard. .
7.5.3.2. Stock standard solutions for analytes which are
liquid in their pure form at room temperature can
be accurately prepared in the following manner.
7.5.3.3. Place about 9.8 mL of MTBE into a 10.0 mL volumetric
flask. Allow the flask to standj unstoppered, for
about 10 minutes to allow solvent film to evaporate
552.2-9
-------
from the inner walls of the volumetric, and weigh to
the nearest 0.1 mg.
7.5.3.4. Use a 10 /iL syringe and immediately add 10.0 /iL of
standard material to; the flask by keeping the
syringe needle just above the surface of the MTBE.
Be sure that the standard material falls dropwise
directly into the MT;BE without contacting the inner
wall of the volumetric.
7.5.3.5. Reweigh, dilute to v'olume, stopper, then mix by
inverting the flask several times. Calculate the
concentration in milligrams' per milliliter from the
net gain in weight.
7.5.4 PRIMARY DILUTION STANDARD (PDS) — Prepare the primary
dilution standard solution by combining and diluting stock
standard solutions with MTBE .(the surrogate' stock standard ..
solution was prepared in Section 7.5.2). This primary
dilution standard solution should be stored at -10°C and
protected from light. It is stable for at least one month
but should be checked before :use for signs of evaporation.
As a guideline to the analyst, the primary dilution standard
solution used in the validation of this method is described
below.
Concentration.
Monochloroacetic acid 60
Monobromoacetic acid 40
Dalapon 40
Dichloroacetic acid 60
Trichloroacetic acid ,20
Bromochloroacetic acid 40
Dibromoacetic acid .20
Bromodichloroacetic acid 40
Chlorodibromoacetic acid 100
Tribromoacetic acid 200
2,3-Dibromopropionic acid (surr.) 100
This primary dilution standard is used to prepare calibration
standards, which comprise five concentration levels of each
analyte with the lowest standard being at or near the MDL of
each analyte. The concentrations of the other standards
should define a range containing the expected sample
concentrations or the working range of the detector.
NOTE: When purchasing commercially prepared standards, solu-
tions prepared in methanol must not be used because it has
been found that the haloacetic acids are subject to
spontaneous methylation when stored in this solvent (12).
552.2-10
-------
7.5.6
Furthermore, tribromoacetic acid has been found to be unsta-
ble in methanol because it undergoes decarboxylation when
stored in this solvent.
7.5.4.1. Include the surrogate analyte, 2,3-dibromopropionic
acid, within the primary dilution standard prepared
in Section 7.5.4. By incorporating the surrogate
into the primary dilution standard, it is diluted
alongside the target analytes in the standard
calibration curve. This is done so that the peaks
for the surrogate and the ester of chlorodibromo-
acetic acid, which elute fairly closely, are
relatively close in size and adequate resolution is
therefore insured. Furthermore, if a sample should
have a very large concentration of chlorodibromo-
acetic acid, it may be impossible to obtain an
accurate measurement of surrogate recovery. If this
happens, reextraction with a higher surrogate
concentration would be an option.
LABORATORY PERFORMANCE CHECK STANDARD (LPC) — A low level '
calibration standard can. serve as the LPC standard.
8. SAMPLE COLLECTION. PRESERVATION AND STORAGE
8.1 SAMPLE VIAL PREPARATION
8.1.1
8.1.2
Grab samples must be collected in accordance with conven-
tional sampling practices (13) using amber glass containers
with TFE-lined screw-caps and capacities of at least 50 ml.
Prior to shipment to the field, add crystalline or granular
ammonium chloride (NH4C1) to the sample container in an
amount to produce a concentration of 100 mg/L in the sample.
For a typical 50 mL sample, 5 mg of ammonium chloride is
added.
NOTE: Enough ammonium chloride must be added to the sample
to convert the free chlorine residual in the sample matrix to
combined chlorine. Typically, the ammonium chloride
concentration here will accomplish that. If high doses of
chlorine are used, additional ammonium chloride may be re-
quired.
8.2 SAMPLE COLLECTION
8.2.1
8.2.2
Fill sample bottles to just overflowing but take care not to
flush out the ammonium chloride.
When sampling from a water tap, open the tap and allow the
system to flush until the water temperature has stabilized
(usually about 3-5 minutes). Remove the aerator so that no
552.2-11
-------
air bubbles can be visibly detected and collect samples from
the flowing system.
8.2.3 When sampling from an open body of water, fill a 1-quart
wide-mouth bottle or 1-liter beaker with sample from a
representative area, and carefully fill sample vials from the
container.
8.2.4 After collecting the sample in the bottle containing the
ammonium chloride, seal the bottle and agitate by hand for 1
min.
8.3 SAMPLE STORAGE/HOLDING TIMES
8.3.1 Samples must be iced or refrigerated at 4°C and maintained at
these conditions away from light until extraction. Synthetic
ice (i.e., blue ice) is not recommended. Holding studies
performed to date have suggested that, in samples preserved
with NH4C1, the analytes are stable for up to 14 days. Since
stability may be matrix dependent, the analyst should verify
that the prescribed preservation technique is suitable for
the samples under study.
8.3.2 Extracts (Section 11.2.7) must be stored at 4°C or less away
from light in glass vials with Teflon-lined caps. Extracts
must be analyzed within 7 days from extraction if stored at
4°C or within 14 days if stored at -10°C or less.
9. QUALITY CONTROL
9.1 Each laboratory that uses this method is required to operate a
formal quality control (QC) program. Minimum quality control
requirements are monitoring the laboratory performance check stan-
dard, initial demonstration of laboratory capability, performance of
the method detection limit study, analysis of laboratory reagent
blanks and laboratory fortified sample matrices, determination of
surrogate compound recoveries in ;each sample and blank, monitoring
internal standard peak area or height in each sample, blank and CCC,
and analysis of QC samples. Additional QC practices may be added.
9.2 LABORATORY PERFORMANCE CHECK STANDARD (LPC)
At the beginning of an analysis set, prior to any calibration
standard or sample analysis and after an initial solvent analysis, a
laboratory performance check standard must be analyzed. This check
standard insures proper performance of the GC by evaluation of the
instrument parameters of detector sensitivity, peak symmetry, and
peak resolution. It furthermore ;serves as a check on the continuity
of the instrument's performance. In regards to sensitivity, it
allows the analyst to ascertain that this parameter has not changed
drastically since the analysis of the MDL study. Inability to
demonstrate acceptable instrument performance indicates the need for
552.2-12
-------
I
re-evaluation of the instrument system. Criteria are listed in
Table 8.
9.2.1 The sensitivity requirement is based on the EDLs published in
this method. If laboratory EDLs differ from those listed in
Table 2, concentrations of the LPC standard may be adjusted
to be compatible with the laboratory EDLs.
9.2.2 If column or chromatographic performance cannot be met, one
or more of the following remedial actions should be taken.
Break off approximately 1 meter of the injector end of the
column and re-install, install a new column, adjust column
flows or modify the oven temperature program.
9.3 INITIAL DEMONSTRATION OF CAPABILITY (IDC)
9.3.1 Calibrate for each analyte of interest as specified in
Section 10. Select a representative fortification
concentration for each of the target analytes.
Concentrations near those in Table 4 are recommended.
Prepare 4-7 replicates laboratory fortified blanks by adding
an appropriate aliquot of the primary dilution standard or
quality control sample to reagent water. (This reagent water
should contain ammonium chloride at the same concentration
as that specified for samples as per Section 8.1.2.) Analyze
the LFBs according to the method beginning in Section 11.
9.3.2 Calculate the mean percent recovery and the standard devia-
tion of the recoveries. For each analyte, the mean recovery
value, expressed as a percentage of the true value, must fall
in the range of 80-120% and the relative standard deviation
should be less than 20%. For those compounds that meet these
criteria, performance is considered acceptable and sample
analysis may begin. For those compounds that fail these
criteria, this procedure must be repeated using 4-7 fresh
samples until satisfactory performance has been demonstrated.
Maintain these data on file to demonstrate initial
capabilities.
9.3.3 Furthermore, before processing any samples, the analyst must
analyze at least one laboratory reagent blank to demonstrate
that all glassware and reagent interferences are under
control.
9.3.4 The initial demonstration of capability is used primarily to
preclude a laboratory from analyzing unknown samples via a
new, unfamiliar method prior to obtaining some experience
with it. As laboratory personnel gain experience with this
method, the quality of data should improve beyond those re-
quired here.
552.2-13
-------
9.3.5 The analyst is permitted to modify GC columns, GC conditions,
internal standard or surrogate compounds. Each time such
method modifications are made, the analyst must repeat the
procedures in Section 9.3.1 through Section 9.3.4 and Sect.
9.4.
9.4 METHOD DETECTION LIMIT STUDY (MDL)
9.4.1. Prior to the analysis of any: field samples, the method
detection limits must be determined. Initially, estimate the
concentration of an analyte which would yield a peak equal to
5 times the baseline noise and drift. Prepare seven
replicate laboratory fortified blanks at this estimated
concentration with reagent water that contains ammonium
chloride at the same concentration as that specified for
samples as per Section 8.1.2'. Analyze the LFB's according to
the method beginning in Section 11.
9 4.2. Calculate the mean recovery land the standard deviation for
each analyte. Multiply the student's t value at 99% confi-
dence and n-1 degrees of freedom (3.143 for seven replicates)
by this standard deviation to yield a statistical estimate of
the detection limit. This calculated value is the MDL.
9.4.3. Since the statistical estimate is based on the preci- sion
of the analysis, an additional estimate of detection can be
determined based upon the noiise and drift of the baseline as
well as precision. This estimate is the EDL (Table 2).
9.5 LABORATORY REAGENT BLANKS (LRB) — Each time a set of samples is
extracted or reagents are changed, a LRB must be analyzed. If the
LRB produces an interferant peak within the retention time window
(Section 12.3) of any analyte that would prevent the determination
of that analyte or a peak of concentration greater than the MDL for
that analyte, the analyst must determine the source of contamination
and eliminate the interference before processing samples. Field
samples of an extraction set associated with an LRB that has failed
the specified criteria are considered suspect.
NOTE: Reagent water containing ammonium chloride at the same
concentrations as in the samples (Section 8.1.2) is used to prepare
the LRB.
9.6 LABORATORY FORTIFIED BLANK (LFB) — Since this method utilizes
procedural calibration standards, which are fortified reagent water,
there is no difference between the LFB and the continuing
calibration check standard. Consequently, the analysis of an LFB is
not required (Section 10.2).
552.2-14
-------
9.7.2.
9.7 LABORATORY FORTIFIED SAMPLE MATRIX (LFM)
9.7.1 Chlorinated water .supplies will usually contain significant
background concentrations of several method analytes espe-
/T?«l? dichloroacetic ^id (DCAA) and trichloroacetic acid
(ICAA). The concentrations of these acids may be equal to or
greater than the fortified concentrations. Relatively poor
accuracy and precision may be anticipated when a large
background.must be subtracted. For many samples, the concen-
trations may be so high that fortification may lead to a
final extract with instrumental responses exceeding the
linear range of the electron capture detector. If this
occurs, the extract must be diluted. In spite of these
problems, sample sources should be fortified and analyzed as
described below. By fortifying sample matrices and calcu-
lating analyte recoveries, any matrix induced analyte bias is
evaluated.
The laboratory must add known concentrations of analytes to
one sample per extract!on set or a minimum of 10% of the
samples, whichever is greater. The concentrations should be
equal to or greater than the background concentrations in the
sample selected for fortification. If the fortification
level is less than the background concentration, recoveries
are not reported. Over time, samples from all routine sample
sources should be fortified.
Calculate the mean percent recovery, R, of the concentration
for each analyte, after correcting the total mean measured
concentration, A, from the fortified sample for the back-
ground concentration, B, measured in.the unfortified sample
i.e.: K
R = 100 (A - B) / C,
where C is the fortifying concentration. In order for the
recoveries to be considered acceptable, they must fall
between 70% and 130% for all the target analytes.
If a recovery .falls outside of this acceptance range, a
matrix induced bias can be assumed for the respective analyte
and the data for that analyte must be reported to the data
user as suspect due to matrix effects.
9.8 ASSESSING SURROGATE RECOVERY
The surrogate analyte is fortified into the aqueous portion of all
continuing calibration standards, samples and laboratory reagent
blanks. The surrogate is a means of assessing method performance in
every analysis from extraction to final chromatographic performance
9.7.3
9.7.4
552.2-15
-------
9.8.1 When surrogate recovery from a sample, blank or CCC is < 70%
or > 130%, check (1) calculations to locate possible errors,
(2) standard solutions for degradation, (3) contamination,
and (4) instrument performance. If those steps do not reveal
the cause of the problem, Reanalyze the extract.
9.8.2 If the extract reanalysis meets the surrogate recovery
criterion, report only data for the reanalyzed extract.
9.8.3 If the extract reanalysis fails the 70-130% recovery
criterion, the analyst should check the calibration by
analyzing the most recently acceptable continuing calibration
check standard. If the CQC fails the criteria of Section
10.2.1, recalibration is In order per Section 10.1. If the
CCC is acceptable, it may be necessary to extract another
aliquot of sample. If the sample re-extract also fails the
recovery criterion, report all data for that sample as
suspect.
9.9 ASSESSING THE INTERNAL STANDARD
9.9.1. The analyst must to monitor the IS response (peak area or
peak height) of all injections during each analysis day.
A mean IS response should be determined from the five point
calibration curve. The IS response for any run should not
deviate from this mean IS response by more than 30%. It is
also acceptable if the IS response of a injection is within
15% of the daily continuing calibration standard IS response.
9.9.2 If a deviation greater than this occurs with an individual
extract, optimize instrument performance and inject a second
aliquot of that extract.
9.9.2.1 If the reinjected aliquot produces an acceptable
internal standard response, report results for that
aliquot.
9.9.2.2 If a deviation of greater than 30% is obtained for
the reinjected extract, the analyst should check the
calibration by analyzing the most recently
acceptable CCC. ;If the CCC fails the criteria of
Section 10.2.1, recalibration is in order per
Section 10.1. If the CCC is acceptable, analysis of
the sample should be repeated beginning with Section
11, provided the sample is still available. Oth-
erwise, report results obtained from the reinjected
extract, but annotate as suspect.
9.10 QUALITY CONTROL SAMPLE (QCS) — At least quarterly, analyze a QCS
from an external source. If measured analyte concentrations are not
of acceptable accuracy, check the entire analytical procedure to
locate and correct the problem source.
552.2-16
-------
9.11 The laboratory may adapt additional QC practices for use with this
?ho ±H f tteC,fiC P:actices that are most productive depend upon
the needs of the laboratory and the nature of the samples For
example, field or laboratory duplicates may be analyzed to assess
the precision of the environmental measurements or field reaqent
blanks may be used to assess contamination of samples under site
conditions, transportation and storage. '»•«*_
10. CALIBRATION AND STANDARDIZATION
10.1 INITIAL CALIBRATION CURVE
10.1.1 Calibration is performed by extracting procedural standards,
i.e ; fortified reagent water, by the procedure set forth in
Section 11. A five-point calibration curve is to be prepared
by diluting the primary dilution standard into MTBE at the
appropriate levels. The desired amount of each MTBE
calibration standard is added to separate 40 mL aliquots of
reagent water to produce a calibration curve ranging from the
detection limit to approximately 50 times the detection
limit. (These MTBE calibration standards should be prepared
so that 20 /jl or less of the solution is added the water
aliquots.) Also, the reagent water used for the procedural
standards contains ammonium chloride at the same concentra-
tion as that in the samples as per Section 8.1.2.
10.1.2 Establish GC operating parameters equivalent to the suggested
specifications in Table 1. The GC system must be calibrated
using the internal standard (IS) technique. Other columns or
conditions may be used if equivalent or better performance
can be. demonstrated.
10.1.2 Five calibration standards are required. The lowest should
contain the analytes at a concentration near to but greater
than the MDL (Table 2) for each compound. The others should
be evenly distributed throughout the concentration ranae
expected in the samples.
10.1.3 Inject 2 >L of each calibration standard extract and tabulate
peak height or area response and concentration for each
analyte and the internal standard.
10.1.4 Generate a calibration curve by plotting the area ratios
(V^is) against the concentration Ca of the five calibration
standards where
Aa is.the peak area of the analyte.
A}s is the peak area of the internal standard.
Ca is the concentration of the analyte.
552.2-17
-------
This curve can be defined as either first or second order.
Also, the working calibration curve must be verified daily by
measurement of one or more calibration standards (Section
10.2). If the response for any analyte falls outside the
predicted response by more than 30%, the calibration check
must be repeated using a freshly prepared calibration stan-
dard. Should the retest fail, a new calibration curve must
be generated.
10.1.5 Alternately, an average relative response factor can be
calculated and used for quantitation. Relative response
factors are calculated for each analyte at the five
concentration levels using the equation below:
RRF
(Aa)(Cis)
(Ais)(Ca)
If the RRF value over the working range is constant (<20%
RSD), the RRF can be assumed to be invariant and the average
RRF used for calculations. Also, the average RRF must be
verified daily by measurement of one or more calibration
standards (Secti-on 10.2). If the RRF for the continuing
calibration standard deviates from the average RRF by more
than 30%, the calibration check must be repeated using a
freshly prepared calibration standard. Should the retest
fail, a new calibration curve must be generated.
10.1.6 A data system may be used to collect the chromatographic
data, calculate relative response factors, or calculate
linear or second order calibration curves.
10.2 CONTINUING CALIBRATION CHECK (CCC)
10.2.1 At least one CCC must be extracted with each set of samples.
A CCC must be analyzed at the beginning of each, analysis set,
after every tenth sample analysis and after the final sample
analysis, to ensure that the instrument is still within
calibration. These checks should be at two different
'concentration levels. Calculate analyte recoveries for all
target analytes. In order for the calibration check to be
considered valid and subsequently for the preceding ten
samples to be considered acceptable with respect to
calibration, recoveries must fall between 70% and 130% for
all the target analytes.
NOTE: Continuing calibration check standards need not
necessarily be different extracts but can be injections from
the same extract as long as the holding time requirements
(Sect. 8.3.2) are met.
552.2-18
-------
I
10.2.2 If this^.critena cannot be met, the continuing calibration
check standard extract is re-injected in order to determine
if the response deviations observed from the initial analysis
are repeated. If this criteria still cannot be met, a second
CCC should be extracted and analyzed or a CCC that has
already been analyzed and has been found to be acceptable
should be run. If this second CCC fails, then the instrument
is considered out of calibration and needs to be
recalibrated.
11. PROCEDURE
11.1 SAMPLE EXTRACTION
11.1.1 Remove the samples from storage (Sect. 8.3.1) and allow them
to equilibrate to room temperature.
11.1.2 Place 40 ml of the water sample into a precleaned 60 ml glass
vial with a teflon-lined screw cap using a graduated
cylinder.
11.1.3 Add 20 ML of surrogate standard (10.0 ,/ig/mL 2,3-dibromo-
propionic acid in MTBE per Section 7.5.2).
NOTE: When fortifying an aqueous sample with either
surrogate or target analytes contained in MTBE, be sure that
the needle of the syringe is well below the level of the
water. After injection, cap the sample and invert once
This insures that the standard solution is mixed well with
the water.
11.1.4 Adjust the pH to less than 0.5 by adding at least 2 mL of
concentrated sulfuric acid. Cap, shake and then check the PH
with a pH meter or narrow range pH paper.
11.1.5 Quickly add approximately 2 g of copper II sulfate
pentahydrate and shake until dissolved. This colors the
aqueous phase blue and therefore allows for the analyst to
better distinguish between the aqueous phase and the organic
phase in this micro extraction.
11.1.6 Quickly add 16 g of muffled sodium sulfate and shake for 3 to
5 minutes until almost all is dissolved. Sodium sulfate is
added to increase the ionic strength of the aqueous phase and
thus further drive the haloacetic acids into the organic
Pu S?: uThe addition of this salt and the copper II sulfate
should be done quickly so that the heat generated from the
addition of the acid (Section 11.1.4) will help dissolve the
S 3 I t S .
552.2-19
-------
11 1 7 Add 4.0 ml MTBE and place on the mechanical shaker for 30
' ' minutes. (If hand-shaken, two minutes is sufficient if
performed vigorously).
11.1.8 Allow the phases to separate for approximately 5 minutes.
11.2 METHYLATION
11 2 1 Usinq a pasteur pipet, transfer approximately 3 ml of the
uppe? MTBE layer to a 15 ml graduated conical centrifuge
tube.
11.2.2 Add l.mL 10% sulfuric acid' in methanol to each centrifuge
tube.
n-2-3
tained.
snugly into the heating 'block to ensure proper heat transfer.
At this stage, methyl ation of the method analytes is at-
tained.
11 2 4 Remove the centrifuge tubes from the heating block (or sand
bath) and allow them to cool before removing the caps.
11 2 5 Add 4 ml saturated sodium bicarbonate solution to each
11 centrifuge tube in 1 ml increments Exercise caution when
adding the solution because the evolution of C02 in this
neutralization reaction is rather rapid.
11 2 6 Shake each centrifuge tube for 2 minutes. As the neutral -
ization reaction moves to completion, it is important to
continue to exercise caution by venting frequently to release
the evolved C02.
11 2 7 Transfer exactly 1.0 ml of the upper MTBE layer to an auto-
sampler vial. A duplicate vial should be filled using the
excess extract.
11 2 8 Add 10 uL of internal standard to the vial to be analyzed.
(25 Mg/mL 1,2,3-trichloropropane in MTBE per Section 7.5.1).
11 2 9 Analyze the samples as soon as possible. The sample extract
may be stored up to 7 days if kept at 4°C or less or up to 14
days if kept at -10°C or less. Keep the extracts away from
light in amber glass vials with Teflon-lined caps.
11.3 GAS CHROMATOGRAPHY
11 3.1 Table 1 summarizes recommended GC operating c°nditio"s.^c
retention times observed using this method. Figure 1 illus-
trates the performance of the recommended primary column with
the method analytes. Figure 2 illustrates the performance of
552.2-20
-------
the recommended confirmation column with the method analytes
Concentrations of the analytes of these chromatograms are
those listed in Table 4 for the fortified reagent water
samples. Other GC columns or chromatographic conditions may
be used if the requirements of Section 9 are met.
11.3.2 Calibrate the system (Section 10.1) or verify the existing
calibration by analysis of a CCC daily as described in
Section 10.2.
11.3.3 Inject 2 /il_ of the sample extract. Record the resulting peak
sizes in area or height units.
11.3.4 If the response for the peak exceeds the working range of the
system, dilute the extract, add an appropriate additional
amount of .internal standard and reanalyze. The analyst must
not extrapolate beyond the calibration range established.
12. DATA ANALYSIS AND CALCULATIONS
12.1 Identify sample components by comparison of retention times to
retention data from the calibration standard analysis. If the
retention time of an unknown peak corresponds, within limits (Sec-
tion 12.2), to the retention time of a standard compound, then the
identification is considered positive. Calculate analyte concentra-
tions in the samples and reagent blanks from the calibration curves
generated in Section 10.1. '
12.2 If an average relative response factor has been calculated (Sect
10.1.5), analyte concentrations in the samples and reagent blanks
are calculated using the following equation:
c - -(-A-a-Cis)
(Ais)(RRF)
12.3 The width of the retention time window used to make identifications
should be based upon measurements of actual retention time varia-
tions of standards over the course of a day. Three times the
standard deviation of a retention time can be used to calculate a
suggested window size for a compound. However, the experience of
the analyst should weigh heavily in the interpretation of
chromatogram.
13. METHOD PERFORMANCE
13.1 In a single laboratory, recovery and precision data were obtained at
three concentrations in reagent water (Tables 3 and 4). The MDL and
EDL data are given in Table 2. In addition, recovery and precision
data were obtained at a medium concentration for dechlorinated tap
water (Table 5), high ionic strength reagent water (Table 6) and
high humectant ground water (Table 7).
552.2-21
-------
14. POLLUTION PREVENTION
14.1 This method utilizes a micro-extraction procedure which requires the
use of very small quantities of organic solvents. This feature
reduces the hazards involved with;the use of large volumes of poten-
tially harmful organic solvents needed for conventional liquid-
liquid extractions. This method also uses acidic methanol as the
derivatizing reagent.
14.2 For information about pollution prevention that may be applicable to
laboratory operations consult "Less is Better: Laboratory Chemical
Management for Waste Reduction" available from the American Chemical
Society's Department of Government Relations and Science Policy,
1155 16th Street N.W., Washington, D.C. 20036.
15. WASTE MANAGEMENT
15.1 Due to the nature of this method there is little need for waste
management. No large volumes of solvents or hazardous chemicals are
used. The matrices of concern are finished drinking water or source
water. However, the Agency requires that laboratory waste manage-
ment practices be conducted consistent with all applicable rules and
regulations, and that laboratories protect the air, water, and land
by minimizing and controlling all releases from fume hoods and bench
operations. Also compliance is required with any sewage discharge
permits and regulations, particularly the hazardous waste identifi-
cation rules and land disposal restrictions. For further informa-
tion on waste management, consult;"The Waste Management Manual for
Laboratory Personnel" also available from the American Chemical
Society at the address in Sect. 14.2.
16.
REFERENCES
1.
4.
Quimby, B.D., Delaney, M.F., Uden. P.C. and Barnes, R.M. Anal.
Chem. 52, 1980, pp. 259-263.
Uden, P.C. and Miller, J.W., J. Am. Water Works Assoc. 75, 1983, pp.
524-527.
Hodgeson, J.W. and Cohen, A.L. anjd Collins, J.D., "Analytical
Methods for Measuring Organic Chlorination Byproducts", Proceedings
Wate.r Quality Technology Conference (WQTC-16), St. Louis, MO, Nov.
13-17, 1988, American Water Works Association, Denver, CO, pp. 981-
1001.
Fair. P.S., Barth, R.C., "Comparison of the Microextraction
Procedure and Method 552 for the Analysis of HAAs and
Chlorophenols", Journal AWWA, November, 1992, pp. 94-98.
552.2-22
-------
7.
8.
9.
10.
11
12.
13.
14.
15.
mc/u iand KT!3en' S'." A SimP]ified Technique for the Measure-
ment of Halogenated Organic Acids in Drinking Water by Electron
Capture Gas Chromatography". Presented at the 28th Pacific Confer-
ence on Chemistry and Spectroscopy, Pasadena, CA, October, 1989
Hodgeson, J W., Collins, J. D., and Becker, D. A., "Advanced Tech-
niques for the Measurement of Acidic Herbicides and Disinfection
Byproducts in Aqueous Samples," Proceedings of the 14th Annual EPA
Conference on Analysis of Pollutants in the Environment, Norfolk,
VA., May 8-9, 1991. Office of Water Publication No. 821-R-92-001
U.S. Environmental Protection Agency, Washington, DC, pp 165-194.
Shorney, Holly L. and Randtke, Stephen J., "Improved Methods for
Haloacetic Acid Analysis", Proceedings Water Quality Technology
Conference, San Francisco, CA, November 6-10, 1994, American Water
Works Association, pp 453-475.
Peters Rund J.B., Erkelens, Corrie, De Leer, Ed W.B. and De Galan
Leo, The Analysis of Halogenated Acetic Acids in Dutch Drinkina
Water", Wat. Res., Vol.25, No.4, 1991, Great Britain, pp 473-477.
"Carcinogens-Working with Carcinogens", Publication No 77-206
Department of Health, Education, and Welfare, Public Health Service
Center for Disease Control, National Institute of Occupational
Safety and Health, Atlanta, Georgia, August 1977.
"OSHA Safety and Health Standards, General Industry", (29CFR1910)
OSHA 2206, Occupational Safety and Health Administration, Washing-
ton, D.C. Revised January 1976.
"Safety In Academic Chemistry Laboratories", 3rd Edition, American
Chemical Society Publication, Committee on Chemical Safety, Washing-
ton, U.L., 1979.
Xie Yuefeng, Reckhow, David A., and Rajan, R.V., "Spontaneous
Methylation of Haloacetic Acids in Methanolic Stock Solutions"
Environ. Sci. Techno!., Vol.27, No.6, 1993, pp!232-1234.
ASTM Annual Book of Standards, Part 31, D3370, "Standard Practice
for Sampling Water", American Society for Testing and Materials
Philadelphia, PA, p. 76, 1980. , '
ASTM Annual Book of Standards, Part 31, D3694, "Standard Practice
for Preparation of Sample Containers and for Preservation" American
Society for Testing and Materials, Philadelphia, PA, p. 679, 1980.
Glaser J. A., Foerst, D. L., McKee, G. D., Quave, S. A. and Budde,
W. L., Environ. Sci. Technol. 15, 1981, pp. 1426-1435.
552.2-23
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TABLE 1. RETENTION DATA AND CHROMATOGRAPHIC CONDITIONS
Analyte
Monochloroacetic Acid (MCAA)
Monobromoacetic Acid (MBAA)
Dichloroacetic Acid (DCAA)
Dalapon
Trichloroacetic Acid (TCAA)
Bromochloroacetic Acid (BCAA)
1,2,3-Trichloropropane (L.S.)
Dibromoacetic Acid (DBAA)
Bromodichloroacetic acid (BDCAA)
Chlorodibromoacetic acid (CDBAA)
2,3-Dibromopropionic acid (SURR)
Tribromoacetic Acid (TBAA)
Retention Time.
l
Column A
13103
17,15
. 17,80
19.08
22.67
23.15
23,70
31.38
32,18
41.57
41.77
49.22
min.
Column B
13.70
17.33
17.88
17.73
20.73
22.87
22.35
30.27
28.55
38.78
39.72
,47.08
Column A: DB-5.625, 30 m x 0.25 mm i.d., 0.25 im film thickness,
Injector Temp. = 200 C, Detector Temp. = 260 C, Helium
Linear Velocity = 24 cm/sec at 35°C, Splitless injection
with 30 s delay
Program: Hold at 35°C for 10 min, ramp to 75°C at 5C°/min. and hold
15 min., ramp to 100°C at. 5C°/min. and hold 5 min, ramp to
135°C at 5C°/min. and hold 2 min.
Column B: DB-1701, 30 m x 0.25 mm i.d., 0.25 /on film thickness, Injec-
tor Temp. = 200 C, Detector Temp. = 260°C, Linear Helium
Velocity = 25 cm/sec at 35°C, splitless injection with 30 s
delay.
Program: Hold at 35°C for 10 min, ramp to 75°C at 5C°/min. and hold
15 min., ramp to 100°C at 5C°/min. and hold 5 min, ramp to
135°C at 5C°/min. and hold '0 min.
552.2-26
-------
TABLE 2. ANALYTE ACCURACY AND PRECISION DATA
AND METHOD DETECTION LIMITS3
LEVEL 1 IN REAGENT WATER
Analyte
MCAA
MBAA
DC.AA
Dalapon
TCAA
BCAA
DBAA
BDCAA
CDBAA
TBAA
Fortified
Cone.
M9/L
0.600
0.400
0.600
0.400
0.200
0.400
0.200
0.400
1.00
2.00
Mean
Meas.
Cone.
M9/L
0.516
0.527
0.494
0.455
0.219
0.498
0.238
0.357
1.19 .
1.91
Std.
Dev.
M9/L
0.087
0.065
0.077
0.038
0.025
0.080
0.021
0.029
0.149
0.261
Rel.
Std.
Dev., %
17
12
16
8.4
11
16
8.8
8.1
12
14
Method
Detection
Limitb
M9/L
0.273
0.204
0.242
0.119
0.079
0.251
0.066
0.091
0.468
0.820
Estimated
Detection
Limit0
M9/L
0.60
0.20
0.24
0.40
0.20
0.25
0.20
0.40
0.75
1.5
a Produced by analysis of seven aliquots of fortified reagent water.
b The MDL is a statistical estimate of the detection limit. To determine the MDL for
each analyte, the standard deviation of the mean concentration of the seven replicates
is calculated. This standard deviation is then multiplied by the student's t-value at
99% confidence and n-1 degrees of freedom (3.143 for seven replicates). The result is
the MDL.
The EDL is defined as either the MDL or a level of a compound in a sample yielding a
peak in the final extract with a signal to noise (S/N) ratio of approximately 5,
whichever is greater.
552.2-27
-------
TABLE 3. ANALYTE ACCURACY AND PRECISION DATA8
LEVEL 2 IN REAGENT WATER
Fortified
Cone.
Analyte M9/L
Monochloroacetic Acid
Monobromoacetic Acid
Dichloroacetic Acid
Dalapon
Trichloroacetic Acid
Bromochloroacetic Acid
Dibromoacetic Acid
Bromodichloroacetic Acid
Chlorodibromoacetic Acid
Tribromoacetic Acid
1.50
1.00
1.50
1.00
0.500
1.00
0.500
1.00
2.50
5.00
Mean
Meas.
Cone.
M9/L
1.42
1.02
1.27
0.935
0.465
0.869
0.477
1.07
2.62
5.19
Std.
Dev.
M9/L.
: 0.103
0.051
, 0.122
0.087
0.048
0.049
0.044
0.098
0.150
0.587
Rel.
Std.
Dev., %
7.3
5.0
9.6
9.3
10
5.6
9.2
9.2
5.7
11 .
Mean
Recovery
%
94.7
102
84.7
93.5
93 .0
86.9
95.4
107
105
104
a Produced by the analysis of seven aliquots of fortified reagent water.
552.2-28
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TABLE 4. ANALYTE ACCURACY AND PRECISION DATA3
LEVEL 4 IN REAGENT WATER
Mean
Fortified Meas.
Cone. Cone.
Analyte /jg/L #g/L
Monochloroacetic Acid
Monobromoacetic Acid
Dichloroacetic Acid
Dalapon
Trichloroacetic Acid
Bromochloroacetic Acid
Dibromoacetic Acid
Bromodichloroacetic Acid
Chlorodibromoacetic Acid
Tribromoacetic Acid
6.00
4.00
6.00
4.00
2.00
4.00
2.00
4.00
10.0
20.0
5.24
4.36
6.89
.. 3.87
1.74
4.33
1.87
3.93
11.4
24.0
Std.
Dev.
M9/L
0.664
0.475
0.782
0.147
0.144
0.402
0.113
0.377
0.866
1.82
Rel.
Std.
Dev., %
13
11
11
3.8
8.3
9.3
6.0.
9.6
7.6
7.6
Mean
Recovery
%
87.3
109
115
96.8
87.0
108 .
93.5
98.2
114
120
Produced by the analysis of seven aliquots of fortified reagent water.
552.2-29
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TABLE 5. ANALYTE ACCURACY AND PRECISION DATAa'b
LEVEL 3 IN DECHLORINATED TAP WATER0
Background
Cone.
Analyte /tg/L
Monochloroacetic Acid
Monobromoacetic Acid
Dichloroacetic Acid
Dalapon
Trichloroacetic Acid
Bromochloroacetic Acid
Dibromoacetic Acid
Bromodichloroacetic Acid
Chlorodibromoacetic Acid
Tribromoacetic Acid .
<0.6
0.420
0.625
<0.4
0.300
1.23
1.27
0.588
1.23
<2.0
Forti-
fied
Cone.
M9/L
3.00
2.00
3.00
2.00 .
1.00
2.00
1.00
2.00
5.00
10.0
Mean
Meas.
Cone.
/ig/L
2.53
2.20
3.77
1.96
1.12
2.91
2.35
2.52
6.36
11.8
Std.
Dev.
M9/L
0.090
0.034
0.096
0.157
0.167
0.062
0.110
0.388
0.502
1.65
Rel.
Std.
Dev.
%
3.6
1.5
2.5
8.0
15
2.1
4.7
15
7.9
14
Mean
Rec.
%
84.3
89.0
105
98.0
82.0
84.0
108
96.6
103
118
0 Produced by analysis of seven aliquots of fortified dechlorinated tap water.
b Background level subtracted.
"Chlorinated surface water from a local utility to which ammonium chloride was added
as the dechlorinating agent.
552.2-30
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TABLE 6. ANALYTE ACCURACY AND PRECISION DATAa'b
LEVEL 3 IN HIGH IONIC STRENGTH WATERC
Background
Cone.
Analyte M9/L
Monochloroacetic Acid
Monobromoacetic Acid
Dichloroacetic Acid
Dalapon
Trichloroacetic Acid
Bromochloroacetic Acid
Dibromoacetic Acid
Bromodichloroacetic Acid
Chlorodibromoacet.ic Acid
Tribromoacetic Acid
0.761
1.47
1.50
0.675
1.01
2.06
4.36
1.07
2.48
4.63
Forti-
fied
Cone.
M9/L.
3.00
2.00
3.00
2.00
1.00
" 2.00
1.00
2.00
5.00
10.0
Mean
Meas.
Cone.
M9/L
3.32
3.19
• 4.44
2.39
1.75
3.71
5.48
3.37
7.94
17.2
Std.
Dev.
M9/L
0.429
0.099
0.264
0.259
0.110
0.269
0.255
0.308
1.00
1.55
ft '
Rel
Std
Dev
%
13
' 3.1
5.9
11
6.3
7.3
4.7
9.1
13
9.0
Mean
Rec
%
85.3
86.0
98.0
85.8
74.0
82,. 5
112
115
109,
126
a Produced by analysis of seven aliquots of fortified high ionic strength water.
b Background level subtracted.
c Chlorinated ground water from a water source displaying a hardness of 460 mg/L as
CaCO,
552.2-31
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TABLE 7. ANALYTE ACCURACY AND PRECISION DATA8
LEVEL 3 IN HIGH HUMIC CONTENT GROUND WATERb
Background
Cone.
Analyte /ig/L
Monochloroacetic Acid
Monobromoacetic Acid
Dichloroacetic Acid
Dalapon
Trichloroacetic Acid
Bromochloroacetic Acid
Dibromoacetic Acid
Bromodichloro acetic Acid
Chlorodibromoacetic Acid
Tribromoacetic Acid
<0.6
<0.4
<0.6
<0.4
<0.2
<0.4
<0.2
<0.4
<1.0
<2.0
Forti-
fied
Cone.
3.00
2.00
3.00
2.00
1.00
2.00
1.00
2.00
5.00
10.0
Mean
Meas.
Cone.
2.91
1.99
2.88
2.00
0.618
1.82
0.715
1.99
5.50
9.67
Std.
Dev.
0.082
0.105
0.104
0.227
0.053
0.059
0.020
0.164
0.218
1.13
Rel.
Std.
Dev.
2.8
5.3
3.6
11
8.6
3.2
2.8
8.2
4.0
12
Mean
Rec.
97.0
99.5
96.0
100
61.8
91.0
71.5
99.5
110
96.7
8 Produced by analysis of seven aliquots of fortified simulated high humic content
ground water.
b Reagent water fortified at 1.0 mg/L with fulvic acid extracted from Ohio River
water. Sample simulates high TOC matrix.
552.2-32
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TABLE 8. LABORATORY PERFORMANCE CHECK SOLUTION
PARAMETER
INSTRUMENT
SENSITIVITY
CHROMATOGRAPHIC
PERFORMANCE
COLUMN
PERFORMANCE
ANALYTE
MCAA
BCAA
CDBAA
SURROGATE. (2S3-DBPA)
CONC,. , pg/mL
IN MTBE
0.006
0.004
0.010
0.010
ACCEPTANCE
CRITERIA
DETECTION OF
ANALYTE;
S/Na > 3
PGFb BETWEEN
0.80 AND 1.15
RESOLUTION0
> 0.50
S/N, a ratio of peak signal to baseline noise.
peak signal - measured as height of peak.
baseline noise - measured as maximum deviation in baseline (in units of height)
over a width equal to the width of the base of the peak.
PGF = Peak Gaussian Factor
1.83 x W,
PGF =
M/2
where W1/2 = the peak width at half height (in sees).
W1/10 = the peak width at one-tenth height (in sees).
This is a measure of the symmetry of the peak.
c Resolution between two peaks is defined by the equation:
t '
R =
where t = the difference in elution times between the two peaks.
Wave = the average peak width of the two peaks (measurements taken at
baseline).
This a measure of the degree of separation of two peaks under specific chromatographic
conditions.
*U.S. GOVERNMENT PRINTING OFFICE: 1 995-650-006/2207 1
552.2-33
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552.2-34
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