:WeJtfto:dJ5133 Determination of Chlorinated Herbicides
1n Drinking Hater
September 1986
Supplement to "Methods for the Determination
of Organic Compounds 1n Finished Drinking
Hater and Raw Source Water"
Physical and Chemical Methods Branch
Environmental Monitoring and Support Laboratory
U. S. Environmental Protection Agency
Cincinnati, Ohio 45268
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METHOD 515: THE DETERMINATION OF CHLORINATED HERBICIDES
IN DRINKING WATER
1. SCOPE AND APPLICATION"
1.1 This method is applicable to the determination of certain
chlorinated acid herbicides in drinking water. This method is
applicable, but not limited to, the analyses of the following
parent acids and salts and esters of these acids. The chemical
form of each acid is not distinguished. Results are calculated and
reported as total free acid.
»
Chemical Abstract Services
Analyte Registry Number (CAS)
2,4-D 94-75-7
2,4-08 94-82-6
Dicamba 1918-00-9
2,4,5-T 93-76-5
2,4,5-TP (Silvex) 93-72-1
Dalapon • 75-99-0
Pentachlorophenol (PCP) 87-86-5
Dinoseb 88-85-7
Picloram 1918-02-1
1.2 The estimated detection limit (EDL) for each analyte above is given
in Table 1 for capillary column chromatography. The EDLs were
determined by the esterification and analyses of replicate 1 mL
acid calibration standards as described in Sect. 7.3. Thus the
variability represented by the EDL is that of the esterification
and analysis portions and not of the total procedure. The method
detection limit (MDL) for each analyte is given in Table 2 for
packed column chromatography.
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 Section 8.3.
1.4 When this method is used to analyze unfamiliar samples for any or
all of the analytes above, identifications should be supported by
at least one additional qualitative technique.
2. SUMMARY OF METHOD
2.1 A measured volume of sample, ca. 1 liter, is acidified to convert
any salts present to the parent acid. The acids and esters are
extracted with ethyl ether. The esters are hydrolyzed and
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converted to acid salts with potassium hydroxide solution. The
aqueous phase containing the add salts 1s then solvent washed to
remove extraneou-s organic material. After acidification the acids
are extracted into organic phase and the sample volume reduced to 5
ml in methyl-t-butyl ether (MTBE) with a K-D concentrator. The
acids are converted to their methyl esters by the use of a
micro-diazomethane generator. The samples are then analyzed by
either packed or capillary column GC using an electron capture
detector (ECD).l
2.2 This method is a modified version of EPA Method 615, "The
Determination of Chlorinated Herbicides in Industrial and Municipal
Wastewater."
3. INTERFERENCES
3.1 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 Section 8.6.
3.1.1 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 thoroughly rinsing with dilute
acid, tap and reagent water. Drain dry, and heat in an oven
or muffle furnace at 400*C for 15 to 30 min. Do not heat
volumetric ware. Thermally stable material, such as PCBs,
might not be eliminated by this treatment. Thorough rinsing
with acetone and pesticide quality hexane 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.
3.1.2 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.
3.2 The acid forms of the herbicides are strong organic acids, which
react readily with alkaline substances and can be lost during
analysis. Glassware and glass wool must be acid-rinsed with (1+9)
hydrochloric acid and the sodium sulfate must be acidified with
sulfuric acid prior to use to avoid this possibility (See Section
6.5).'
3.3 Organic acids and phenols, especially chlorinated compounds, cause
the most direct interference with the determination. Alkaline
hydrolysis and subsequent extraction of the basic solution remove
many chlorinated hydrocarbons and phthalate esters that might
otherwise interfere with the electron capture analysis.
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3.4 Matrix Interferences may be caused by contaminants that are
coextracted from the sample. The extent of matrix Interferences
may vary from source to source, depending upon the municipality
sampled. Specific cleanup procedures have not yet been identified
for drinking water samples.
4. SAFETY
4.1 The toxicity or carcinogenitity 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 reduced to the lowest possible
level by whatever means available. 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 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 identified3-5 for the information of the analyst.
4.2 Diazomethane is a toxic carcinogen and can explode under certain
conditions. The following precautions must be followed:
4.2.1 Use only in a well ventilated hood - do not breath vapors.
4.2.2 Use a safety screen.
4,2.3 Use mechanical pipetting aides.
4.2.4 Do not heat above 90*C - EXPLOSION may result.
4.2.5 Avoid grinding surfaces, ground glass joints, sleeve
bearings, glass stirrers - EXPLOSION may result.
4.2.6 Store away from alkali metals - EXPLOSION may result.
4.2.7 Solutions of dlazomethane decompose rapidly in the presence
of solid materials, such as copper powder, calcium chloride,
and boiling chips.
5. APPARATUS AND MATERIALS
5.1 Sample bottle - Amber borosilicate or flint glass, 1-liter or
1-quart volume, fitted with screw caps lined with TFE-fluorocarbon
or aluminum foil. If amber bottles are not available, protect
samples from light. The container ..and cap liner must be washed,
rinsed.with acetone or methylene chloride, and dried before use to
minimize contamination.
5.2 Glassware (All specifications are suggested. Catalog numbers are
included for illustration only).
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5.2.1 Separatory funnels - 60-mL and 2000-
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5.9.1 Column 1 - Capillary, DB-1, 30 m x 0.32 mm ID, 0.25 urn film
thickness or equivalent.
5.9.2 Column 2 - Capillary, DB-5, 30m x 0.32 mm ID, 0.25 urn film
thickness'or equivalent.
5.9.3 Column 3 - 180 cm long x 4 mm ID glass, packed with 1.5X
SP-2250/1.95* SP-2401 on Supelcoport (100/120 mesh) or
equivalent.
5.9.4 Column 4 - 180 cm long x 4 mm ID glass, packed with 5%
OV-210 on Gas Chrom Q (100/120 mesh) or equivalent.
5.9.5 Detector - Electron capture. This detector has proven
effective in the analysis of drinking water and was used to
develop the method performance statements in Section 15.
Alternative detectors, including a mass spectrometer, may be
used in accordance with the provisions described in Section
12.1.
6. REAGENTS
6.1 Reagent water - Reagent water is defined as a water in which an
interferent is not observed at the method detection limit of each
parameter of interest.
6.2 Methanol - Pesticide quality or equivalent.
6.3 Ethyl ether - (Burdick and Jackson Product No. 107 or equivalent).
Nanograde, redistilled in glass if necessary. Ethers must be free
of peroxides as Indicated by EM Quant test strips • Procedures
recommended for removal of peroxides are provided with the test
strips. Ethers must be periodically tested (monthly) for peroxide
formation during use.
6.4 Methyl-t-butyl ether - (Burdick and Jackson Product No. 242 or
equivalent). Nanograde, redistilled in glass if necessary Same
peroxide precautions apply as for ethyl ether.
6.5 Sodium sulfate - (ACS) Granular, acidified, anhydrous. Heat treat
in a shallow tray at 400*C for a minimum of 4 h to remove
phthalates and other interfering organic substances. Alterna-
tively, Soxhlet extract with methylene chloride for 48 h. Acidify
by slurrying 100 g sodium sulfate with enough ethyl ether to just
cover the solid. Add 0.1 ml concentrated sulfuric acid and mix
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 mix-ture. It must be below pH 4. Store at 130*C.
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6.6 Hydrochloric acid (1+9) - (ACS) Add one volume of cone. HC1 to 9
volumes reagent water.
6.8 Potassium hydroxide solution - 37% aqueous solution (W:V).
Dissolve 37 g ACS grade KOH pellets 1n reagent water and dilute to
100 ml.
6.9 Sulfuric acid solution (1+1) - Slowly add 50 ml H2$04 (sp. gr.
1.84) to 50 ml of reagent water.
6.10 Sulfuric acid solution (1+3) - Slowly add 25 ml ^504 (sp. gr.
1.84) to 75 ml of reagent water. Store and maintain at 4*C.
6.11 Carbitol - (Diethylene glycol monoethyl ether), ACS. Available
from Aldrich Chemical Co.
6.12 Diazald - (N-methyl-N-nitroso-p-toluenesulfonamide), ACS.
Available from Aldrich Chemical Co.
6.13 Diazald Solution - Prepare a solution containing 10 grams 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 colored bottle with a teflon-lined screw
cap.
6.14 Silicic acid - Chromatographic grade, nominal 100 mesh. Store at
130'C.
6.15 Bo.iling chips - Approximately 10/40 mesh. Heat at 400*C for 1 h or
Soxhlet extract with methylene chloride.
6.16 Stock standard solutions (1.00 ug/uU - Stock standard solutions
can be prepared from pure standard materials or purchased as
certified solutions.
6.16.1 Prepare stock standard solutions by accurately weighing
about 0.0100 grams of pure acids. Dissolve the material in
pesticide quality MTBE and dilute to volume in a 10-mL
volumetric flask. Larger volumes can be used at the con-
venience of the analyst. If compound purity is certified at
96X 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.
6.16.2 Transfer the stock standard solutions into Telfon-sealed
screw-cap vials. 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.
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6.16.3 Secondary dilution standard - Use stock standard solutions
to prepare secondary dilution standard solutions that .
contain the analytes 1n methyl-t-butyl ether. The secondary
dilution standard should be prepared at a concentration such
that 50 to 200 uL of the solution can be added to 25, 50, or
100 ml of WTBE to prepare calibration solutions that bracket
the working concentration range.
7. CALIBRATION
7.1 Establish GC operating parameters equivalent to those indicated in
Tables 2 and 3.
7.2 For each analyte of interest, prepare acid calibration standards at
a minimum of three concentration levels by adding accurately
measured volumes of one or more secondary dilution standards to a
volumetric flask and diluting to volume with MTBE. One of the
external standards should be representative of a concentration
near, but greater than the detection limits. The other
concentrations should corres- pond to the range of concentrations
expected in the sample concentrates or should define the working
range of the detector.
7.3 Prepare methyl ester calibration standards by esterification of
1.00 ml volumes of the working standards as described in Section
11. Inject 1 to 2 wL of each calibration standard and tabulate
peak height or area responses against the mass of free acid
represented by the injection. The results can be used to prepare a
calibration curve for each parameter. Alternatively, the ratio of
the response to the mass injected, defined as the calibration
factor (CF), can be calculated for each parameter at each standard
concentra- tion. If the relative standard deviation of the
calibration factor is less than 10% over the working range, the
average calibration factor can be used in place of a calibration
curve.
7.4 The working calibration curve or calibration factor must be
verified on each working shift by the preparation of one or more
calibration standards. If the response for any analyte varies from
the predicted response by more than *10%, the test must be repeated
using a fresh calibration standard. Alternatively, a new
calibration curve or calibration factor must be prepared for that
parameter.
8. QUALITY CONTROL
8.1 Each laboratory using this method is required to operate a formal
quality control (QC)program. The minimum requirements of this
program consist of an initial demonstration of laboratory capa-
bility and the analysis of spiked samples as a continuing check on
performance. The laboratory is required to maintain performance
records to define the quality of data thus generated. Specific
minimum QC requirements consist of:
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8.1.1 Demonstration of the ability to generate acceptable accuracy
and precision with this method (Section 8.3).
8.1.2 Definitien of method performance criteria for each spike
concentration and analyte being measured (Section 8.4).
8.1.3 Demonstration of continuing laboratory performance by
monitoring analyte recoveries from spiked samples
-(Section 8.5).
8.1.4 Analysis of reagent blanks to detect introduction of reagent
and glassware interferences (Section 8.6).
8.1.5 Confirmation of detected analytes (Section 8.7).
8.1.6 Additional quality assurance (QA) procedures as required
(Section 8.7).
8.2 In recognition of the rapid advances occurring in chromatography,
the analyst is permitted certain options to improve the separations
or lower the cost of measurements. Each time such modifications to
the method are made, the analyst is required to repeat the
procedure in Section 8.3.
8.3 Accuracy and Precision - To establish the ability to generate
acceptable accuracy and precision, the analyst must perform the
following operations.
8.3.1 For each compound to be measured, using stock standards,
prepare a QC check sample concentrate 1n methanol at a
concentration of 5 ug/mL.
8.3.2 Using a pipet, add 1.00 ml of the check sample concentrate
to each of a minimum of four 1000-mL aliquots of reagent
water. Analyze the aliquots according to the method
beginning in Section 10.
8.3.3 Calculate the average percent recovery (R), and the standard
deviation of the percent recovery (s), for the results.
8.3.4 Using the appropriate data from Table 2, determine the
recovery and single operator precision expected for the
method, and compare these results to the values calculated
in Section 8.3.3. If the data are not comparable, review
potential problem areas and repeat the test.
8.4 Method Performance Criteria - The analyst must calculate method
performance criteria and define the performance of the laboratory
for each spike concentration and parameter being measured.
8.4.1 Calculate upper and lower control limits for method
performance as follows:
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Upper Control Limit (UCL) - R + 2 s
Lower Control Limit (LCL) - R - 2 s
where R and s are calculated as 1n Section 8.3.3. The UCL
and LCL can be used to construct control charts^ that are
useful in observing trends 1n performance.
8.4.2 The laboratory must develop and maintain separate accuracy
statements of laboratory performance for drinking water
samples. An accuracy statement for the method is defined as
R * s. The accuracy statement should be developed by the
analysis of four aliquots of drinking water as described in
Section 8.3.2. followed by the calculation of R and s.
Alternatively, the analyst may use four drinking water data
points gathered through the requirement for continuing
quality control in Section 8.5. The accuracy statements
should be updated regularly.6
8.5 Analyte Recoveries - The laboratory is required to collect in
duplicate a portion of their samples to monitor spike recoveries.
The frequency of spiked sample analysis must be at least 10% of all
samples or one spiked sample per month, whichever is greater. One
aliquot of the sample must be spiked and analyzed as described in
Section 8.3. If the recovery for a particular parameter does not
fall within the control limits for method performance, the results
reported for that parameter in all samples processed as part of the
same set must be qualified as described in Section 13.3. The
laboratory should monitor the frequency of data so qualified to
ensure that it remains at or below 5%.
8.6 Reagent Blanks - Before processing any samples, the analyst must
demonstrate through the analysis of a 1-liter aliquot of reagent
water that all glassware and reagents interferences are under
control. Each time a set of samples is extracted or there is a
change in reagents, a laboratory reagent blank must be processed as
a safeguard against laboratory contamination.
8.7 Additional QC - It is recommended that the laboratory adopt
additional quality assurance practices for use with this method.
The specific practices that are more productive depend upon the
needs of the laboratory and the nature of the samples. Field
duplicates may be analyzed to monitor the precision of the sampling
technique. When doubt exists over the identification of a peak on
the chromatogram, confirmatory techniques such as GC with a dis-
similar column, specific element detector, or mass spectrometer
must be used. Whenever possible, the laboratory should perform
analysis of QC materials and participate in relevant performance
evaluation studies.
9. SAMPLE COLLECTION, PRESERVATION, AND HANDLING
9.1 Grab samples must be collected in glass containers. Conventional
sampling practices? should be followed; however, the bottle must
not be prerinsed with sample before collection.
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9.2 The samples must be Iced or refrigerated at 4*C from the time of
collection until extraction.
9.3 All samples must be extracted within seven days, and completely
analyzed within 40 days of extraction.
10. SAMPLE EXTRACTION, HYDROLYSIS AND CONCENTRATION
10.1 Mark the water meniscus on the side of the sample bottle for later
determination of sample volume. Pour the entire sample into a
2-liter separatory funnel. Check the pH with wide-range pH paper
and adjust to pH less than 2 with sulfuric acid (1+1). 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. Alternatively, the
sample volume may be determined by weighing before and after the
sample bottle is emptied.
10.2 Add 150 at ethyl ether to the sample bottle, cap the bottle and
shake 30 s to rinse the walls. Transfer the solvent to the
separatory funnel and extract the sample by 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, centri-
fugation or other physical means. Drain the aqueous phase into a
1000-mL Erlenmeyer flask and collect the extract in a 250-mL
ground-glass Erlenmeyer flask containing 2 ml of 37% potassium
hydroxide solution. Approximately 80 ml of the ethyl ether will
remain dissolved in the aqueous phase.
10.3 Add a 50-mL volume of ethyl ether to a sample bottle and repeat the
extraction a second time, combining the extracts in the Erlenmeyer
flask. Perform a third extraction in the same manner.
10.4 Add 15-mL reagent water and 1 or 2 clean boiling chips to the
250-mL flask and attach a three-ball Snyder column. Prewet the
Snyder column by adding 1 ml ethyl ether to the top. Place the
apparatus on a hot water bath (60 to 65*C), such that the bottom of
the flask is bathed in the water vapor. Although the ethyl ether
will evaporate in about 15 min, continue heating for a total of 60
min, beginning from the time the flask is placed on the water
bath. Remove the apparatus from the bath and let stand at room
temperature for at least 10 min.
10.5 Transfer the solution to a 60-mL separatory funnel using 5 to 10 ml
of reagent water. Wash the basic solution twice by shaking for one
min with 20-mL portions of ethyl ether. Discard the organic
phase. The acid salts remain in the aqueous phase.
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10.6 Acidify the contents of the separatory funnel to pH 2 by adding 2
fit of cold (4*C) sulfuric add (1+3). Test the pH with Indicator
paper. Add 20 ml ethyl ether and shake vigorously for 2 min.
Drain the aqueous layer Into the 250-mL Erlenmeyer, then pour the
organic layer into a 125-mL Erlenmeyer flask containing about 5 g
of acidified, anhydrous sodium sulfate. Repeat the extraction
twice more with 10-mL aliquots of ethyl ether, combining all
solvent in the 125-mL flask. Allow the extract to remain in
contact with the sodium sulfate for approximately 2 h.
10.7 Assemble a Kuderna-Oanish (K-0) concentrator by attaching a 10-mL
concentrator tube to a 500-mL evaporative flask.
10.8 Pour the combined extract through a funnel plugged with acid
washed glass wool, and collect the extract in the K-0 concentra-
tor. Use a glass rod to crush any caked sodium sulfate during the
transfer. Rinse the Erlenmeyer flask and column with 20 to 30 ml
of ethyl ether to complete the quantitative transfer.
10.9 Add 1 to 2 clean boiling chips to the evaporative flask and attach
a three-ball Snyder column. Prewet the Snyder column by adding
about 1 ml ethyl ether to the top. Place the K-0 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 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 1 ml, remove the K-0 apparatus and allow it to drain and
cool for at least 10 min.
10.10 Remove the Snyder column and rinse the flask and its lower joint
into the concentrator tube with 1 to 2 ml of ethyl ether using a
disposable pipet or syringe. Add 1 ml MTBE and a fresh boiling
chip. 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-0 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-0 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 3-4 ml with MTBE.
11. ESTER IFICATION OF ACIDS
11.1 Assemble the diazomethane generator shown in Figure 1 in a hood.
The collection vessel is a 10-15 ml vial, equipped with a
teflon-lined screw cap and maintained at 0-5*C.
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11.2 Add a sufficient amount of ethyl ether to tube 1 to cover the first
Impinger. Add 5 ml of MBTE to the collection vial. Set the
nitrogen flow at 5-10 cnn/mln. Add 2 ml Dlazald solution (Sect.
6.13) and 1.5 mL of 37% KOH solution to the second implnger.
Connect the tubing as shown and allow the N£ flow to purge the
dlazomethane from the reaction vessel Into the collection vial for
30 m1n. Cap the vial when^collection is complete and maintain at
0-5*C. When stored at 0-5*C this dlazomethane solution may be used
over a period of 48 h.
11.3 To each concentrator tube containing sample or standard, add 250 uL
methanol and 0.5 ml of dlazomethane solution (Sect. 11.2). Dilute
to 5.0 ml with WTBE.
11.4 Seal the concentrator tubes with teflon or glass stoppers and store
in the hood at room temperature for 5 min.
11.5 Open the concentrator tube and destroy any unreacted diazomethane
by adding approximately 0.2 g activated silica to the samples. The
samples are now ready for analysis by GC. Analyze as soon as
possible. The samples may be stored in the stoppered concentrator
tubes at 0-4*C if the analysis cannot be performed immediately.
The analysis should be performed within 24 hours.
12. GAS CHROMATOGRAPHY
12.1 Tables 2 and 3 summarize the recommended operating conditions for
packed and capillary chromatography. Tables 1 and 2 contain
estimated retention times and detection limits that can be achieved
• by this method. Examples of the separations achieved for the
methyl esters are shown in Figures 2 and 3. Other columns,
chromatographic conditions, or detectors may be used if the
requirements of Section 8.3 are met.
12.2 Calibrate the system daily as described in Section 7.
12.3 Inject 1 to 5 wL of the sample extract for packed columns or 1-2 uL
for capillary columns. Record the resulting peak size in area or
peak height units. An automated system that consistently injects a
constant volume of extract may also be used.
12.4 The width of the retention time window used to make identifica-
tions 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.
12.5 If the response for the peak exceeds the working range of the
system, dilute the extract and reanalyze.
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13. CALCULATIONS
13.1 Determine the concentration of Individual compounds 1n the
sample. Calculate the amount of the free acid Injected from the •
peak response using the calibration curve or calibration factor in
Section 7.2.2. The concentration in the sample can be calculated
as follows:
Concentration, wg/L » (A) (V )
t
(V ) (V J
1 s
where:
A a Amount of material injected, in nanograms.
V^ 3 Volume of extract injected in vl.
V^ » Volume of total extract in uL.
V - Volume of water extracted in liters.
13.2 Report results in micrograms per liter as acid equivalent without
further correction for recovery data. When duplicate and spiked
samples are analyzed, report all data obtained with the sample
results.
13.3 For samples processed as part of a set where the laboratory spiked
sample recovery falls outside of the control limits in Section 8.4,
data for the affected parameters should be considered unacceptable.
14. METHOD PERFORMANCE
14.1 The MDL is defined as the minimum concentration of a substance that
can be measured and reported with 99% confidence that the value is
above zero.l® The detection limits listed in Tables 1 and 2 were
obtained from reagent water with an electron capture detector&
14.2 In single laboratory evaluations, the average recoveries presented
in Tables 4 and 5 were obtained for Column 1 of Table 1 and column
3 of Table 2.H The standard deviations of the percent
recoveries of these measurements are also included in Tables 4 and
5.
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REFERENCES
1. Goerlitz, D.G. and Lamar, W.L., "Oetennlnation of Phenoxy Acid
Herbicides in Water by Electron-Capture and Microcoulometric Gas
Chromatography," U. S. Geol. Survey Water Supply Paper 1817-C (1967).
2. ASTM Annual Book of Standards, Part 31, 03694, "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,
August, 1977."
4. "OSHA Safety and Health Standards, General Industry," (29CFR1910),
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. "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.
7. ASTM Annual Book of Standards, Part 31, D3370, "Standard Practice for
Sampling Water," American'Society for Testing and Materials,
Philadelphia, PA, p. 76, 1980.
8. McNair, H.M. and Bonelli, E.J., "Basic Chromatography," Consolidated
Printing, Berkeley, California, p. 52, 1969.
9. Eichelberger, O.W., Harris, L.E., Budde, W.L. "Reference Compound to
Calibrate Ion Abundance Measurement in Gas Chromatography-Mass
Spectrometry," Analytical Chemistry. £7, 995 (1975).
10. Glaser, J.A., D.L. Foerst, G.D. McKee, S.A. Quave, and W.L. Budde,
"Trace Analyses for Wastewaters," Environ. Sci. Techno!.. 15, 1426, 1981.
11. Pressley, T.A. and Longbottom, J.E., "The Determination of Chlorinated
Herbicides in Industrial and Municipal Wastewater - Method 615."
Environmental Monitoring and Support Laboratory, U. S. Environmental
Protection Agency, Cincinnati, OH 45268, January 1982.
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TABLE 1
CHROMATOGfcAPHIC CONDITIONS AND DETECTION LIMITS
CAPILLARY COLUMNS
Analyte
(as methyl ester)
Dalapon
Dlcamba
2,4-D
PCP
2,4,5-TP
2,4.5-T
2,4-DB
Dinoseb
Picloram
Retention Time, min.
Column 1* Column 2*
3.78
12.32
14.63
18.65
18.98
19.76
22.78
23.47
26.46
2.99
10.89
13.78
16.98
18.65
20.25
24.61
32.33
Estimated Detection*
Limit (EDL) uq/L
.001
.01
.01
.0005
.01
.01
.07
.01
.07
* The EDL is defined here as the student t factor times the standard
deviation of at least 7 replicate analyses, of a 1 nt calibration standard
at a concentration near but above the EDL. These EDL values were obtained
on Column 1.
* Column 1: DB-1
Column 2: DB-5
-------
TABLE 2
CHROMATOGRAPHIC CONDITIONS AND METHOD DETECTION LIMITS
PACKED COLUMNS
Analyte
(as methyl ester)
Dicamba
2,4-0
2,4,5-TP
2,4,5-T
2,4-08
Dinoseb
Column 3
1.2
2.0
2.7
3.4
4.1
11.2
Retention Time
(min.)
Column 4
1.0
1.6
2.0
2.4
—
^ •
Method
Detection
Limit uq/L
0.27
1.2
0.17
0.20
0.91
0.07
Column 3 conditions: Supelcoport (100/120 mesh) coated with 1.5% SP-2250/
1.95% SP-2401 packed in a 1.8 m long x 4 mm ID glass column with 95%
argon/5% methane carrier gas at^a flow rate of 70 mL/min. Column
temperature: isothermal at 185*C. An electron capture detector was used to
measure MDL.
Column 4 conditions: Gas Chrom Q (100/120 mesh) coated with 5% OV-210
packed in a 1.8 m long x 4 mm ID glass column with 95% argon/5% methane
carrier gas at a flow rate of 70 mL/min. Column temperature: isothermal at
185*C.
-------
TABLE 3
Recommended Capillary GC Operating Conditions
Column Type: 08-1 or OB-5
Film Thickness: 0.25 »m
Column Dimension: 30 m x 0.32 mm
Helium Linear Velocity: 28-29 cm/sec
Injection Port Temp: 200*C
Detector Temp: Column 3 - 290*C
Column 4 - 200*C
Temperature Program: Column 1 - DB-1. Inject at
100*C and program immediately
at 12"C/min to 200*C and hold
until picloram elutes.
Column 2 - DB-5. Inject at
80*C and hold 2 min. Program
at 16*C/min to 160*C and hold
until picloram elutes.
-------
TABLE 4
SINGLE OPERATOR ACCURACY AND PRECISION AS DETERMINED BY
CAPILLARY COLUMN GCa
Analyte
Dalapon
Dicainba
2,4-0
PCP
Si 1 vex
2,4,5-T
2,4-DB
Dinoseb
Picloram
Spike Levelb
uq/L
4.05
4.13
4.01
1.01
4.05
4.23
4.02
4.12
4.01
AVGC
Recovery %
91
87
87
63
87
85
63
56
62
* RSO
9
11
11
11
13
13
32
19
14
aoata obtained on column 1
&The matrix is reagent water
CAT! results based on seven replicate analyses
-------
TABLE 5.
SINGLE OPERATOR ACCURACY AND PRECISION*
FOR PACKED COLUMN GC
Parameter
2,4,0
2,4-DB
Dicamba
2,4,5-T
2,4,5-TP
Oalapon
-
Di noseb
Sample
Type
RW
DW
OW
RW
DW
DW
RW
DW
DW
RW
DW
DW
RW
DW
DW
RW
DW
DW
DW
Spike
- (uq/L)
10.9
10.1
200
10.3
10.4
208
1.2
1.1
22.2
1.1
1.3
25.5
1.0
1.3
25.0
23.4
23.4
0.5
102
Mean
Recovery
(*)
75
77
65
93
93
77
79
86
82
85
83
78
88
88
72
66
96
86
81
Standard
Deviation^)
4
4
5
3
3
6
7
9
6
6
4
5
5
4
5
8
13
4
3
*A11 results based upon seven replicate analyses.
RW » Reagent water
DW » Drinking water
-------
nllrog«n
rubb«r itopp*r
tub* I
Figure 1. Dlazomethane generator.
tub* 2
glott tubing
Collection
Thermos or
cryogenic cooler
-------
012345
Retention Time (M1n)
Figure 2. Gas chroroatogram of methyl esters of chlorinated
herbicides on Column 1. For conditions, see Table 1
-------
XI
VI
_*«
" •
61
o
M
to
"I
°\
«l
CM
2
o
CD
O
CM
§
•t>
•*
•
n
Figure 3. Gas Chromatogram of MethyT Esters of Chlorinated Herbicides
on CoTumrTB. For Conditions, "See Table 4.
------- |