600486503
5279 . .
METHODS FOR THE DETERMINATION
OF ORGANIC COMPOUNDS IN
FINISHED DRINKING WATER
AND RAW SOURCE WATER
June 1985
Revised November 1985
PHYSICAL AND CHEMICAL METHODS BRANCH
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
U. S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
U.S. Environmental Protection Agency
Region V, Library
230 South Dearborn Street
Chicago, Illinois 60604
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DISCLAIMER
This report has been reviewed by the Environmental Monitoring and
Support Laboratory, U. S. Environmental Protection Agency, and approved for
publication. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
11
j,S. Environmental Protection Agency
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FOREWORD
Environmental measurements are required to determine the quality of
ambient waters and the character of waste effluents. The Environmental
Monitoring and Support Laboratory - Cincinnati, conducts research to:
0 Develop and evaluate techniques to measure the presence and
concentration of physical, chemical, and radiological pollutants in
water, wastewater, bottom sediments, and solid waste.
0 Investigate methods for the concentration, recovery, and
Identification of viruses, bacteria and other microbiological
organisms in water; and to determine the responses of aquatic
organisms to water quality.
0 Develop and operate an Agency-wide quality assurance program to
assure standardization and quality control of systems for
monitoring water and wastewater.
° Develop and operate a computerized system for instrument automation
leading to improved data collection, analysis, and quality control.
Under authority of the Safe Drinking Water Act and the National Interim
Primary Drinking Water Regulations, the U. S. Environmental Protection
Agency establishes test procedures for monitoring contaminants in public
water supplies. The test procedures in this document are designed to
measure volatile organic compounds in such waters prior to or after final
treatment.
Robert I. Booth, Director
Environmental Monitoring and Support Laboratory
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ABSTRAC1
The methods contained in this report describe the requirements for the
analysis of drinking water and raw source water for 60 volatile organic
compounds. The methods were prepared to be used for monitoring for volatile
synthetic organic compounds (VOC) at low concentrations in such matrices, as
proposed in 40 CFR 141.24. The methods may also be used for the proposed
monitoring requirement for unregulated contaminants in 40 CFR 141.40.
Included are sample collection and preservation procedures, instructions for
preparation of standards, required operating conditions and quality control
requirements.
iv
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PREFACE
On November 13, 1985, the U.S. Environmental Protection Agency published
(50 FR 46902) proposed National Drinking Water Regulations for eight vola-
tile synthetic organic chemicals (VOCs) and proposed monitoring requirements
for these eight VOCs, tetrachloroethene and 51 other volatile compounds.
Three methods in this report (Methods 502.1, 503.1, and 524.1) are proposed
for use for the regulated contaminants, and, in conjunction with Method 504,
for the proposed monitoring requirement.
The Agency is committed to avoid the needless proliferation of methods,
however, the evolution of measurement technology and the timing of regula-
tory actions have resulted in a number of similar methods. To avoid confu-
sion, the following discussion of the relationship of these methods to
previous editions is provided.
Method 502.1 is the third generation method for volatile organohalides.
Produced originally as Method 501.1 for the measurement of total trihalo-
methanes as defined and required in 40 CFR Part 141.30. It was incorporated
into 40 CFR Part 141.30 on November 29, 1979. The method was extended and
formatted to its current broad scope as Method 502.1 in April 1981 and made
available by the Environmental Monitoring and Support Laboratory-Cincinnati
(EMSL-Cincinnati) to support the recommended maximum contaminant levels
(RMCLs) for VOCs proposed on June 12, 1984. This current edition, which
replaces the April 1981 version of 502.1, focuses on the specific analytes
in the VOC MCL and the monitoring proposals. The major changes in the
method reflected in this version include a strictly prescribed preservation
procedure and a maximum holding time for samples. Since the basic
analytical procedure has not been technically changed since approved for
trihalomethanes, accommodations have been made in the method for total
trihalomethane measurements, if free chlorine quenching techniques are
practiced. Although the Agency has not at this time proposed the method for
approval in Part 141.30, such a proposal is under consideration.
Method 503.1, as included, is a revision of the method prepared in April
1981 and made available by EMSL-Cincinnati to support the RMCL proposal for
VOCs. The current revision, which replaces the 1981 version, focuses on the
specific analytes in the VOC MCL and monitoring proposals and establishes
preservation procedures and a maximum holding time for the samples.
Method 504 is a relatively new method developed to measure low concen-
trations of 1,2-dichloroethane (ED8) and l,2-dibromo-l-3-chloropropane
(DBCP). The proposed monitoring requirement cites this method exclusively
for these two compounds. Method 524.1 is a restricted version of the
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general GC/MS procedure for volatiles described in Method 524 in February
1983, ana subsequently approved for trfhalomethane measurements. The
principal changes incorporated in this method include a focus on the
specific analytes in the VOC MCL and monitoring proposals and establishes
preservation procedures and a maximum holding time for samples. Since the
basic analytical procedure has not changed since approved for trihalo-
methanes, accommodations have been made in the method for total trihalo-
methane measurements if free chlorine quenching techniques are practiced.
Although the Agency has not at this time proposed the method for approval in
Part 141.30 such a proposal is under consideration.
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CONTENTS
Page
Di sc 1 aimer. . i i
Foreword i i i
Abstract i v
Preface <> v
Acknowledgements * vi i i
Method 502.1 - Volatile Halogenated Organic Compounds
in Water by Purge and Trap Gas Chromatography.... ......!
Method 503.1 - Volatile Aromatic and Unsaturated Organic
Compounds in Water by Purge and Trap Gas Chromatography 28
Method 504 - Measurement of 1,2-Dibromoethane (EDB) and
l,2-Dibromo-3-chloropropane (D8CP) in Drinking Water by
Microextraction and Gas Chromatography .56
Method 524.1 - Volatile Organic Compounds in Water by
Purge and Trap Gas Chromatography/Mass Spectrometry 71
vii
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ACKNOWLEDGMENTS
These methods have been prepared by the staff of the Environmental
Monitoring and Support Laboratory - Cincinnati (EMSL-Cincinnati) with the
support and cooperation of the Office of Drinking Water, U. S. Environmental
Protection Agency, Washington, D. C. Special acknowledgments are due for
technical contributions during the preparation of these procedures to the
staffs of the Technical Support Division, Office of Drinking Water, and of
the Water Engineering Research Laboratory, Office of Research and
Development, Cincinnati, Ohio. Jim Longbottom was responsible for preparing
the combined methods package which is based upon earlier versions of Methods
502.1, 503.1 developed by Thomas Bellar, and Method 524 developed by Ann
Alford-Stevens, James Eichelberger, and William Budde. New data on sample
preservation and holding time, presented in this update, were developed by
Thomas Bellar, Robert Slater, Jr., and Kent Sorrel!.
viii
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METHOD 502.1. VOLATILE HALOGENATEO ORGANIC COMPOUNDS
IN WATER BY PURGE AND TRAP GAS CHROMATOGRAPHY
1. SCOPE AND APPLICATION
1.1 This method is applicable for the determination of various
halogenated volatile compounds in finished drinking water, raw
source water, or drinking water in any treatment stage. (1) The
method may be used to calculate total trihalomethane (TTHM)
concentrations as defined and required in 40 CFR, Part 141.30, if a
reducing agent is added as described in Sect. 7.1.2. The following
compounds can be determined by this method:
Analyte
Bromobenzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
^Carbon tetrachloride
Chlorobenzene
Chloroethane
Chloroform
bis-2-Chloroisopropyl ether
Chloromethane
2-Chlorotoluene
4-Chlorotoluene
Dibromochloromethane
1,2-Oibromoethane
Dibromomethane
1,2-DiChlorobenzene
1,3-Dich1orobenzene
1,4-OiChlorobenzene
Oichlorodi f1uoromethane
v-l,l-0iChloroethane
1,2-Oichloroethane
1,1-Di ch1oroethene
cis-l,2-Dichloroethene
trans-1,2-Di ch1oroethene
1,2-Oi ch1oropropane
1,3-Oichloropropane
2,2-Oichloropropane
CAS No.
108-86-1
74-97-5
75-27-4
75-25-2
74-83-9
56-23-5
108-90-7
75-00-3
67-66-3
108-60-1
74-87-3
95-49-8
106-43-4
124-48-1
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
156-59-2
156-60-5
78-87-5
142-28-9
590-20-7
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Analyte CAS Mo.
1,1-Qichloropropene 563-58-6
Methylene chloride 75-09-2
Pentachloroethane 76-01-7
1,1,1,2-Tetrach1oroethane 630-20-6
1,1,2,2-Tetrachloroethane 79-34-5
Tetrachloroethene 127-18-4
v 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
Vinyl chloride 75-01-4
1.2 Single laboratory accuracy and precision data show that this
procedure is useful for the detection and measurement of
multi-component mixtures spiked into carbon filtered finished water
and raw source water at concentrations between 0.20 and 0.40
with method detection limits (MDL) (2) generally less than
0.01 wg/L. Method detection limits for several of the listed
analytes are presented in Table 1 (1). Some laboratories may not
be able to achieve these detection limits since results are
dependent upon instrument sensitivity and matrix effects.
Determination of complex mixtures containing partially resolved
compounds may be hampered by concentration differences'larger than
a factor of 10. This problem commonly occurs when finished
drinking waters are analyzed because of the relatively high
trihalomethane content. When such samples are analyzed, chloroform
will affect the method detection limit for 1,2-dichloroethane.
1.3 Based upon similarities in structure with other analytes in the
scope, 2,2-dichloroproane was included in the November 13, 1985
proposed monitoring regulation although supporting accuracy and
precision data are not available for inclusion in this method.
1.4 This method is recommended for use only by analysts experienced in
the measurement of purgeable organics at the low ug/L level or by
experienced technicians under the close supervision of a qualified
analyst. It is also recommended for use only with a purge and trap
system devoted to the analysis of low level samples.
2. SUMMARY OF METHOD
2.1 Organohalides and other highly volatile organic compounds 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 an inert gas to desorb trapped sample
components onto a gas chromatography (GC) column. The gas
chromatograph is temperature programmed to separate the method
analytes which are then detected with a halogen specific detector.
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2.2 A second chromatographic column is described that can be used to
confirm GC identifications and measurements. Alternatively,
confirmatory analyses may be performed by gas chromatography/mass
spectrometry (GC/MS) according to Method 524.1 if sufficient
material is present.
3. INTERFERENCES
3.1 Samples may be contaminated during shipment or storage by diffusion
of volatile organics through the sample bottle septum seal. Field
reagent blanks (Sect. 9.1.1) must be analyzed to determine if
contamination has occurred.
3.2 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
1n the trap during the purge operation. Analyses of field reagent
blanks (Sect. 9.1.1) and laboratory reagent blanks (Sect. 9.1.2)
provide information about the presence of contaminants. When
potential Interfering peaks.are noted in laboratory reagent blanks,
»the analyst must eliminate the-problem before analyzing samples.
Subtracting blank values from sample results is not permitted.
3.3 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, laboratory reagent blanks must be analyzed until system
memory 1s reduced to an acceptable level. See Sect. 9.1.2.
3.4 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. SAFETY
4.1 The toxfcity or carcinogenicity of chemicals used in this method
has not been precisely defined; each chemical should be treated as
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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 (3-5) for the information of the analyst.
4.2 The following method analytes have been tentatively classified as
known or suspected human or mammalian carcinogens: carbon
tetrachlorJde, bis-2-chloroisopropyl ether, 1,2-dichlorethane,
1,1,2,2-tetrachloroethane, 1,1,2-trichloroethane, chloroform,
1,2-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.
5. APPARATUS AND EQUIPMENT
5.1 SAMPLE CONTAINERS - 40-mL to 120-mL screw cap vials (Pierce #13075
or equivalent) each equipped with a PTFE-faced silicons septum
(Pierce #12722 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 in a 105*C
oven for one hour, then remove and allow to cool in an. area known
to be free of organics.
5.2 PURGE AND TRAP SYSTEM - The purge and trap system consists of three
separate pieces of equipment: purging device, trap, and desorber.
Systems are comrnercially available from several sources that meet
all of the following specifications.
5.2.1 The all glass purging device (Figure 1) must be designed to
accept 5-mL samples with a water column at least 3 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 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. ~"
5.2.2 The trap 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 (see Figure 2). If it is not
necessary to analyze for dichlorodifluoromethane, the
charcoal can be eliminated and the polymer increasedoto fill
2/3 of the trap. If only compounds boiling above 35°C are
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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/nrin Vent the trap effluent to the room, not
to the analytical column. Prior to daily use, the trap
should be conditioned for 10 minutes at 180"C with
baclcflushing. 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.
5.2.3 The^desorber must be capable of rapidly heating the trap to
180"C. The polymer section of the trap should not be heated
higher than 200 C or the Hfe expectancy of the trap will
decrease. Trap failure 1s characterized by a pressure drop
1n excess of 3 pounds per square inch across the trap during
purging or by poor bromoform sensitivities. The desorber
design illustrated in Figure 2 meets these criteria.
5.2.4 Figures 3 and 4 show typical flow patterns for the
purge-sorb and desorb mode.
5.3 GAS. CHROMATOGRAPHY SYSTEM '
5.3.1 The GC must be capable of temperature programming and should
be equipped with variable-constant differential flow
controllers so that the column flow rate will remain
constant throughout desorptlon and temperature program
operation. The column oven may need to be cooled to <30°C
(Sect. 10.3); therefore, a subambient oven controller may be
required.
5.3.2 Two gas chromatography columns are recommended. Column 1 is
a highly efficient column that provides outstanding
separations for a wide variety of organic compounds. Column
1 should be used as the primary analytical column unless
routinely occurring analytes are not adequately resolved.
Column 2 is recommended for use as a confirmatory column
when GC/MS confirmation is not available. Retention times
for the listed analytes on the two columns are presented in
Table 1.
5.3.2.1 Column 1 - 1.5 to 2.5 m x 0.1 in ID stainless steel
or glass, packed with 1% SP-1000 on Carbopack-8
(60/80 mesh) or equivalent. The flow rate of the
helium carrier gas is established at 40 mL/min. The
column temperature is programmed to hold at 45"C for
three min, increased to 220*C at 8°C/min, and held
at 220°C for 15 min or until all expected compounds
have eluted. During handling, packing, and
programming, active sites can be exposed on the
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Carbopack-B packing which can result in tailing peak
geometry and poor resolution of many constituents.
To protect the analytical column, pack the first 5
cm of the column with 3% SP-1000 on Chromosorb-W
(60/80 mesh) followed by the Carbopack-B packing.
Condition the precolumn and the Carbopack columns
with carrier gas flow at 220"C overnight. Pneumatic
shocks and rough treatment of packed columns will
cause excessive fracturing of the Carbopack. If
pressure in excess of 60 psi is required to obtain
40 mL/min carrier flow, the column should be
repacked. A sample chromatogram obtained with
Column 1 is presented in Figure 5.
5.3.2.2 Column 2 - 1.5 to 2.5 m long x 0.1 in ID stainless
steel or glass, packed with n-octane chemically
bonded on Porisil-C (100/120 mesh) or equivalent.
The flow rate of the helium carrier gas is
established at 40 mL/min. The column temperature is
programmed toehold at 50°C for three^min, increased
to 170°C at 6°C/min, and held at 170*C for four min
or until all expected compounds have eluted. A
sample chromatogram obtained with Column 2 is
presented in Figure 6.
S.3.3 An electrolytic conductivity or microcoulometric detector is
required. These halogen-specific systems eliminate
mi sidentifications due to non-organohalides which are
coextracted during the purge step. A Tracer Hall Model
700-A detector was used to gather the single laboratory
accuracy and precision data shown in Tables 2 and 3. The
operating conditions used to collect these data are as
follow:
Reactor tube: Nickel 1/16 in OD
Reactor temperature: 810^C
Reactor base temperature: 250*C
Electrolyte: 100% n-propyl alcohol
Electrolyte flow rate: 0.8 mL/min
Reaction gas: Hydrogen at 40mL/min
Carrier gas: Helium at 40 mL/min
5.4 SYRINGE AND SYRINGE VALVES
5.4.1 Two 5-mt glass hypodermic syringes with Luer-Lok tip.
5.4.2 Three 2-way syringe valves with Luer ends.
5.4.3 One 25-uL micro syringe with a 2 in x 0.006 in ID, 22" bevel
needle (Hamilton #702N or equivalent).
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5.4.4 Micro syringes - 10, 100 uL.
5.4.5 Syringes - 0.5, 1.0, and 5-mL, gas tight with shut-off valve.
5.5 MISCELLANEOUS
5.5.1 Standard solution storage containers - 15-mL bottles with
PTFE-Hned screw caps.
6. REAGENTS AND CONSUMABLE MATERIALS
6.1 TRAP PACKING MATERIALS
6.1.1 2,6-Diphenylene oxide polymer, 60/80 mesh, chromatographic
grade (Tenax GC or equivalent).
6.1.2 Methyl sllicone packing - OV-1 (3%) on Chromosorb-W, 60/80
mesh or equivalent.
6.1.3 Silica gel - 35/60 mesh, Davison, grade 15 or equivalent.
6.1.4 Coconut charcoal - Prepare from Barnebey Cheney, CA-580-26
lot #M-2649 by crushing through 26 mesh screen.
6.2 COLUMN PACKING MATERIALS
6.2.1 1% SP-1000 on 60/80 mesh Carbopack-8 or equivalent.
6.2.2 n-Octane chemically bonded on Porasil-C, 100/120 mesh
(Durapak or equivalent).
6.2.3 3% SP-1000 on 60/80 mesh Chromosorb-W or equivalent.
6.3 REAGENTS
6.3.1 Methanol - demonstrated to be free of analytes.
6.3.2 Reagent water - water meeting specifications in Sect.
9.1.2. 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 m1n 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.
6.3.3 Hydrochloric acid (1*1) - Carefully add measured volume of
cone. HC1 to equal volume of reagent water.
6.3.4 Vinyl chloride - 99.92 pure vinyl chloride is available from
Ideal Gas Products, Inc., Edison, Mew Jersey and from
Matheson, East Rutherford, New Jersey. Certified mixtures
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of vinyl chloride in nitrogen at 1.0 and 10.0 ppm are
available from several sources.
6.3.5 Reducing agent - crystalline sodium thiosulfate, ACS Reagent
Grade or sodium sulfite, ACS Reagent Grade.
6.4 STANDARD STOCK SOLUTIONS - These solutions may be purchased as
certified solutions or prepared from pure standard materials using
the following procedures:
6.4.1 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 and weigh to the nearest 0.1 mg.
6.4.2 If the analyte is a liquid at room temperature, use a 100-uL
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.
6.4.3 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.
6.4.4 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.
6.5 SECONDARY DILUTION STANDARDS - Use standard stock solutions to
prepare secondary dilution standard solutions that contain the
analytes in methanol. The secondary dilution standards should be
prepared at concentrations that can be easily diluted to prepare
aqueous calibration solutions (Sect. 8.1) that will bracket the
working concentration range. Store the secondary dilution standard
solutions with minimal headspace and check frequently for signs of
deterioration or evaporation, especially just before preparing
calibration solutions for them. Storage times described for stock
standard solutions in Sect. 6.4.4 also apply to secondary dilution
standard solutions.
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7. SAMPLE COLLECTION, PRESERVATION, AND STORAGE
7.1 SAMPLE COLLECTION
7.1.1 Replicate field reagent blanks 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 empty sample bottles. Wherever a set of
samples is shipped and stored, it must be accompanied by
field reagent blanks.
7.1.2 For samples collected to determine compliance with total
trfhalomethane regulations (40 CFR Part 141.30), add 2.5 to
3 mg reducing agent (Sect. 6.3.5) per 40 mL to the empty
sample bottles and blanks just prior to shipping to the
sampling site.
7.1.3 Collect all samples in duplicate. Fill sample bottles to
overflowing. Mo air bubbles should pass through the sample
as the bottle is filled, or be trapped in the sample when
the bottle is sealed.
7.1.4 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 from the flowing stream.
7.1.5 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 duplicate sample
bottles from the 1-quart container,
7.2 SAMPLE PRESERVATION
7.2.1 Adjust the pH of the duplicate samples and the field reagent
blanks to <2 by carefully adding one drop of 1:1 HC1 for
each 20 mL of sample volume.(7) Seal the sample bottles,
PFTE-face down, and shake vigorously for one minute,
7.2.2 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 shipmentawith
sufficient ice to ensure that they will be at 4*C on arrival
at the laboratory,
7.3 SAMPLE STORAGE
7.3.1 Store samples and field reagent blanks together at 4*C until
analysis. The sample storage area must be free of organic
solvent vapors.
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7.3.2 Analyze all samples within 14 days of collection. Samples
not analyzed within this period must be discarded and
replaced.
8. CALIBRATION AND STANDARDIZATIOM
8.1 CALIBRATION
8.1.1 A set of at least five calibration standards containing the
method analytes is needed. More than one set of calibration
standards may be required. One calibration standard should
contain each analyte at a concentration approaching but
greater than the method detection limit (Table 1) for that
. compound; the other standards should contain analytes at
concentrations that define the range of the method.
8.1.2 To prepare a calibration standard, add an appropriate volume
of a secondary dilution standard solution to an aliquot of
reagent water in a volumetric container. Do not add less
than 20 uL of an alcoholic standard to the reagent water or
poor precision will result. Use a 25-uL microsyringe and
rapidly inject the alcoholic standard into the water.
Remove the needle as quickly as possible after injection.
Aqueous standards are not stable and should be discarded
after one hour unless sealed and stored as described in
Sect. 7.2.2.
8.1.3 Starting with the standard of lowest concentration, analyze
each calibration standard according to Sect. 10 and tabulate
peak height or area response 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 (<1Q% 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.
8.1.4 The working calibration curve or calibration factor must be
verified on each working day by the measurement of one or
more calibration standards. If the response for any analyte
varies from the predicted response by more than *20S, the
test must be repeated using a fresh calibration standard.
If the results still do not agree, generate a new
calibration curve or use a single point calibration standard
as described in Sect. 8.1.5.
8.1.5 Single point calibration is a viable alternative to a
calibration curve. Prepare single point standards from the
secondary dilution standards in methanol. The single point
standards should be prepared at a concentration that
produces a response close (±20%) to that of the unknowns.
-------
Do not use less than 20 ul of the secondary dilution
standard to produce a single point calibration standard in
reagent water.
8.1.6 As a second alternative to a calibration curve, internal
standard calibration techniques may be used. The following
organohalides are recommended for this purpose:
2-bromo-l-chloropropane or 1,4-dichlorobutane. The internal
Standard is added to the sample just before purging. Check
the validity of the internal standard calibration factors
daily by analyzing a calibration standard.
8.1.7 Calibration for vinyl chloride using a certified gaseous
mixture of vinyl chloride in nitrogen can be accomplished by
the following steps.
8.1.7.1 Fill the purging device with 5.0 ml of reagent water
or aqueous calibration standard.
8.1.7.2 Start to purge the aqueous mixture. Inject a known
volume (between 100 and 2000 uL) 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. Do not inject
the standard through the aqueous sample inlet
needle. Inject the gaseous standard before five min
of the 11-min purge time have elapsed.
8.1.7.3 Determine the aqueous equivalent concentration of
vinyl chloride standard injected with the equation:
S » 0.51 (C)(V) per liter
where S » Aqueous equivalent concentration
of vinyl chloride standard in ug/L;
C » Concentration of gaseous standard in ppm;
V » Volume of standard injected in milli-
liters.
8.2 INSTRUMENT PERFORMANCE - Check the performance of the entire
analytical system daily using data gathered from analyses of
reagent blanks, standards, duplicate samples, and the laboratory
control standard (Sect. 9.2.2).
8.2.1 All of the peaks contained in the standard chromatograms
must be sharp and symmetrical. Peak tailing significantly
in excess of that shown in the method chromatograms (Figures
5 and 6) must be corrected. Tailing problems are generally
traceable to active sites on the GC column or the detector
operation. If only the compounds eluting before chloroform
-------
give random responses or unusually wide peak widths, are
poorly resolved, or are missing, the problem is usually
traceable to the trap/desorber. If only brominated
compounds show poor peak geometry or do not properly respond
at low concentrations, repack the trap. Excessive detector
reactor temperatures can also cause Tow bromoform response.
If negative peaks appear in the chromatogram, replace the
ion exchange column and replace the electrolyte in the
detector.
8.2.2 Check the precision between replicate analyses. A properly
operating system should perform with an average relative
standard deviation of less than 10%. Poor precision is
generally traceable to pneumatic leaks, especially around
the sample purger and detector reactor inlet and exit,
electronic problems, or sampling and storage problems.
Monitor the retention times for each organohalide using data
generated from calibration standards and the laboratory
control standard. If individual retention times vary by
more than 10% over an 8-h period or do not fall within 10%
of an established norm, the source of retention data
variance must be corrected before acceptable data can be
generated.
9. QUALITY CONTROL
9.1 MONITORING FOR INTERFERENCES
9.1.1 Field Reagent Blanks - A field reagent blank (Sect. 7.1.1)
is a sealed bottle of reagent water that accompanies a set
of sample bottles from the laboratory to a sampling site and
back. Analyze a field reagent blank along with each sample
set. If the field reagent blank contains a reportable level
of any analyte, analyze a laboratory reagent blank as
described in Sect. 9.1.2. If the contamination is not
detected in the laboratory reagent blank, the sampling or
transportation practices have caused the contamination. In
this case, discard all samples in the set and resample the
site.
9.1.2 Laboratory Reagent Blanks - A laboratory reagent blank is a
5-mL aliquot of reagent water analyzed as if it were a
sample. Analyze a laboratory reagent blank each time fresh
reagent water is prepared and as necessary to identify
sources of contamination. The laboratory reagent blank
should represent less than 0.01 ug/L response or less than
10% interference for those compounds that are monitored.
9.2 ASSESSING ACCURACY
9.2.1 At least quarterly, analyze a quality control check sample
obtained from the U.S. Environmental Protection Agency,
-------
Environmental Monitoring and Support Laboratory (EMSL),
Quality Assurance Branch, Cincinnati. If measured analyte
concentrations are not within acceptance limits provided
with the sample, check the entire analytical procedure to
locate and correct the problem source.
9.2.2 After every 10 samples, and preferably in the middle of each
day, analyze a laboratory control standard. Calibration
standards may not be used for accuracy assessments and the
laboratory control standard may not be used for calibration
of the analytical system.
9.2.2.1 Laboratory Control Standard Concentrate - If
internally prepared laboratory control standards are
used to provide the routine assessment of accuracy,
they should be prepared from a separate set of stock
standards. From stock standards prepared as
described in Section 6.4, add 500 uL of each stock
standard to methanol in a 10-ml volumetric flask and
adjust to volume.
9.2.2.2 Laboratory Control Standard - Add 20 uL of the
control standard concentrate to 100 mL of reagent
water in a 100-mL volumetric flask and mix well.
9.2.2.3 Analyze a 5-mL aliquot of the laboratory control
standard as described in Sect. 10. For each analyte
in the laboratory control standard, calculate the
percent recovery (P^) with the equation:
P. , . 10° Si
~
where S-j » the analytical result from the
laboratory control standard, in ug/L; and
T-j * the known concentration of the spike,
in ug/L.
9.2.3 At least annually, the laboratory should participate in
formal performance evaluation studies, where solutions of
unknown concentrations are analyzed and the performance of
all participants is compared.
9.3 ASSESSING PRECISION
9.3.1 Precision assessments for this method are based upon the
analysis of field duplicates (Sect. 7.1). Analyze both
sample bottles for at least 10% of all samples. To the
extent practical, the samples for duplication should contain
reportable levels of most of the analytes.
-13-
-------
9.3.2 For each analyte in each duplicate pair, calculate'the
relative range (RR-j) with the equation:
RR. = 1QO Ri
Xi
where Rj = the absolute difference between the
duplicate measurements X]_ and Xj, in
ug/l
the average concentration found
X2J/2), in >,g/L.
9.3.3 Individual relative range measurements are pooled to
determine average relative range or to develop an expression
of relative range as a function of concentration.
10. PROCEDURE
10.1 INITIAL CONDITIONS - 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.
10.2 SAMPLE INTRODUCTION AND PURGING
10.2.1 Remove the plungers from two 5-mL syringes and attach a
closed syringe valve to each. Warm the sample 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 syringe, and compress the sample. Open the
syringe valve and vent any residual air while adjusting the
sample volume to 5.0 mL. If applicable, add 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.
10.2.2 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 (Figures 1 and 3).
10.3 SAMPLE OESORPTION - After the 11-min purge, attach the trap to the
chromatograph , adjust the purge and trap system to the desorb mode
(Figure 4) and initiate the temperature program sequence of the gas
chromatograph. Introduce the trapped materials to the GC column by
rapidly heating the trap to 180°C while backf lushing the trap with
an inert gas between 20 and 60 mL/min for 4.0 ± 0.1 min.
-14-
-------
If rapid heating cannot be achieved,9the GC column must be used as
a secondary trap by cooling it to 30"C (subambient temperature if
poor peak geometry and random retention problems persist) instead
of the initial operating temperature for analysis. While the
extracted sample is being introduced into the gas chromatograph,
empty the purging device using the sample syringe and wash the
chamber with two 5-mL flushes of reagent water. After the purging
device has been emptied, leave the syringe valve open to allow the
purge gas to vent through the sample introduction needle.
10.4 TRAP RECONDITIONING - After desorbing the sample for four min,
recondition the trap by returning the purge and trap system to the
purge mode. Wait 15 s, then close the syringe valve on the purging
device to begin gas flow through the trap. Maintain the trap
temperature at 180*C. After approximately 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.
11. CALCULATIONS
11.1 Identify each organohalide in the sample chromatogram by comparing
the retention time of the suspect peak to retention times generated
by the calibration standards and the laboratory control standard
(Sect. 8.2.2).
11.2 Determine the concentration of the unknowns 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 Peak height sample Concentration of
unknown (ug/L) = Peak height standard * standard (ug/L)
11.3 Report the results for the unknown samples in ug/L. Round off the
results to the nearest 0.1 ug/L or two significant figures.
12. ACCURACY AND PRECISION
12.1 Single laboratory (EMSL-Cincinnati) accuracy and precision for the
organonalides spiked in Ohio River water and carbon-filtered tap
water are presented in Table 2.(1)
12.2 This method was tested by 20 laboratories using drinking water
spiked with various organohalides at six concentrations between 8
and 505 ug/L. Single operator precision, overall precision, and
method accuracy were found to be directly related to the
concentration of the analyte. Linear equations to describe these
relationships are presented in Table 3.(8)
-------
13, REFERENCES
1. "The Determination of Halogenated Chemicals in Uater by the Purge
and Trap Method, Method 502.1," U.S. Environmental Protection
Agency, Environmental Monitoring and Support Laboratory,
Cincinnati, Ohio 45268, April, 1981.
2. Glaser, J.A., D.L. Foerst, G.D. McKee, S.A. Quave, and W.L. Budde,
"Trace Analyses for Wastewaters," Environ. Sci. Techno1., 15, 1426,
1981.
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. "Gas Chromatographic Analysis of Purgeable Halocarbon and Aromatic
Compounds in Drinking Water Using Two Detectors in Series,"
Kingsley, 8.A., Gin, C., Coulson, D.M., and Thomas, R.F., Water
Chlorination, Environmental Impact and Health Effects, Volume 4,
Ann Arbor Science.
7. Bellar, T.A. and J.J. Lichtenberg, "The Determination of Synthetic
Organic Compounds in Water by Purge and Sequential Trapping
Capillary Column Gas Chromatography," U.S. Environmental Protection
Agency, Environmental Monitoring and Support Laboratory,
Cincinnati, Ohio 45268.
8. "EPA Method Validation Study 23, Method 601 (Purgeable
Halocarbons)," U.S. Environmental Protection Agency, Environmental
Monitoring and Support Laboratory, Cincinnati, Ohio 45268.
-------
Table 1. RETENTION TIMES AND METHOD DETECTION LIMITS
(MDL) FOR ORGANOHALIDES
Analyte
Chloromethane
Dichlorodifluoromethane
Vinyl chloride
Chloroethane
Methylene chloride
Trichlorofluorome thane
1 , 1-Oi ch 1 oroethene
Bromochloromethane
1 , 1-Oi chl oroethane
tr ans-1 , 2-Oi ch 1 oroethene
c i s-1 , 2-Di ch 1 oroethene
Chloroform
1,2-Dichloroethane
Oibromomethane
1,1,1-Tri chl oroethane
Carbon tetrachloride
Bromodi ch 1 oromethane
Dichloroacetonitrile(b)
1, 2-Di chl oropropane
1 , 1-Oi chl oropropene
Tri chl oroethene
1,3-Oi chl oropropane
Dibromochl oromethane
1, 1,2-Tri chl oroethane
1,2-Dibromoethane
2-Chloroethylethyl ether(b)
2-Chloroethyl vinyl ether(b)
Bromoform
1,1,1,2-Tetrachloroethane
1,2,3-Trichloropropane
Ch 1 orocyc 1 ohex ane ( b )
1,1, 2, 2-Tetrachl oroethane
Tetrach 1 oroethene
Pentachloroethane(c)
1-Ch 1 orocyc 1 ohexene ( b )
Chlorobenzene
1 ,2-Di bromo-3-ch 1 oropropane
Bromobenzene
2-Chlorotoluene
bis-2-Chloroisopropyl ether
1 , 3-Oi ch 1 orobenzene
1,2-Oichlorobenzene
1,4-Di chl orobenzene
(a) = Not determined.
(b) a Compound not included
Retention
Column 1
90
157
160
200
315
431
476
509
558
605
605
641
684
698
756
781
819
884
895
904
948
973
989
991
1046
1056
1080
1154
1163
1279
1283
1297
1300
1300
1345
1451
1560
1626
1927
1931
2042
2094
2127
in proposed
Time (sec)
Column 2
317
(a)
317
521
607
(a)
463
760
754
563
726
725
921
895
786
664
877
(a)
997
(a)
787
(a)
997
1084
1131
(a)
(a)
1150
1302
(a)
(a)
(a)
898
(a)
1186
1130
(a)
(a)
1320
(a)
1346
1411
1340
monitoring requirement.
MDL
(ug/L)
0.01
(a)
0.006
0.008
(a)
(a)
0.003
(a)
0.002
0.002
0.002
0.002
0.002
(a)
0.003
0.003
0.002
0.04
(a)
(a)
0.001
(a)
(a)
0.007
0.03
0.02
0.02
0.02
(a)
(a)
(a)
0.01
0.001
(a)
(a)
0.001
0.03
(a)
(a)
(a)
(a)
(a)
(a)
(c) * Pentachl oroethane apparently decomposes to tetrachl oroethene in the
analytical system.
-17-
-------
Table 1. (CONTINUED)
Column 1 Conditions: Carbopack B(60/80 mesh) coated with 1% SP-1000 packed
in an 8 ft x 0.1 in ID stainless steel or glass column with helium carrier
gas at 40 ml/min flow rate. Column temperature held at 40°C for 3 min then
programmed at 8*C/min to 220°C and held for 15 min.
Column 2 conditions: Porisil-C (100/120 mesh) coated with chemically bonded
n-octane packed in a 6 ft x 0.1 in ID stainless steel or glass column with
helium carrier gas at 40 ml/min flow rate. eColumn temperature held at 50*C
for 3 min then programmed at 6*C/min to 170*C and held for 4 min.
-18-
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Table 3. SINGLE ANALYST PRECISION, OVERALL PRECISION,
AND ACCURACY FOR ORGANOHALIDES IN DRINKING WATER
Single Analyst
Analyte
Bromod i ch 1 oromethane
Bromoforra
Carbon Tetrachloride
Chlorobenzene
Chloroe thane
Chloroform
Chi oromethane
Di bromoch 1 oromethane
1 , 2-Oi ch 1 orobenzene
1 , 3-Oi ch 1 orobenzene
1 , 4-Oi ch 1 orobenzene
1,1-Oichloroethane
1,2-Dichl oroethane
1,1-Oichloroethene
trans-1 , 2-Di ch 1 oroethene
1 , 2-Oi ch loropropane
Methyl ene Chloride
1,1,2,2-Tetrachloroethane
Tetrachl oroethene
1,1, 1-Tri ch 1 oroethane
1 , 1 ,2-Tr i ch 1 oroethane
Trichl oroethene
Trichl orof 1 uoromethane
Vinyl Chloride
Precision
0.131 * 1.41
0.107 + 0.20
0.107 + 1.57
0.077* 1.71
0.071+ 0.65
0.051+ 5.58
0.281 + 0.27
0.107 + 1.55
0.121 + 2.02
0.151+ 0.64
0.091 + 0.39
0.091 * 0.47
0.067 + 1.69
0.121 + 0.13
0.161 + 0.29
0.191 - 0.61
0.081 + 1.04
0.091 - 1.42
0.177 + 0.96
0.147- Q.33
0.067 + 0.99
0.137+ 0.23
0.227 + 0.03
0.147 - 0.17
Overal 1
Precision
0.187 + 3.06
0.247 + 1.25
0.207 + 1.09
0.167 + 1.43
0.197 + 0.39
0.097 + 6.21
0.497 + 1.51
0.237 + 0.91
0.177+ 2.26
0.247 + 1.48
0.157 + 0.39
0.187+ 1.13
0.187 + 1.21
0.317 - 0.71
0.247 + 0.95
0.27X - 0.10
0.177 + 2.43
0,207 + 1.65
0.257 + 0.58
0.277- 0.76
0.197 + 0.69
0.327 - 0.57
0.307 + 0.64
0.327 + 0.07
Accuracy
as Mean
Recovery (7)
l.OOC + 0.96
1.02C - 1.81
l.OOC - 2.20
l.OOC - 1.39
1.08C - 1.97
0.90C + 3.44
0.91C - 0.99
0.98C + 2.89
0.91C + 1.12
0.91C - 0.13
0.91C + 0.26
0.93C - 2.04
1.03C - 0.41
1.03C - 1.16
0.98C - 1102
0.98C + 1.19
0.97C - 1.50
0.92C - 0.82
0.96C + 0.35
0.92C + 0.02
0.84C + 0.83
0.92C - 0.10
0.92C + 1.21
1.06C - 1.86
7 m Mean recovery, in
C » True value for the concentration, in ug/L
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METHOD 503.1. VOLATILE AROMATIC AND (JNSATURATED ORGANIC
COMPOUNDS IN WATER BY PURGE AND TRAP GAS CHROMATOGRAPHY
1. SCOPE AND APPLICATION
1.1 This method is applicable for the determination of various volatile
aromatic and unsaturated compounds in finished drinking water, raw
source water, or drinking water in any treatment stage.(1) The
following compounds can be determined by this method:
Analyte CAS No.
Benzene 71-43-2
Bromobenzene 108-86-1
n-8utylbenzene 104-51-8
sec-Butyl benzene 135-98-8
tert-Sutylbenzene 98-06-6
Chlorobenzene 108-90-7
2-Chlorotoluene 95-49-S
4-Chlorotoluene 106-43-4
1,2-Oichlorobenzene 95-50-1
1,3-Oichlorobenzene 541-73-1
1,4-Dichlorobenzene 106-46-7
Ethyl benzene 100-41-4
Hexachlorobutadiene 87-68-3
Isopropylbenzene 98-82-8
4-Isopropyltoluene 99-37-6
Naphthalene . 91-20-3
n-Propylbenzene 103-65-1
Styrene 100-42-5
Tetrachloroethene 127-18-4
Toluene 108-88-3
1,2,3-TriChlorobenzene 87-61-6
1,2,4-Trichlorobenzene 120-82-1
Trichloroethene 79-01-6
1,2,4-Trimethylbenzene 95-63-6
1,3,5-Trimethylbenzene 108-67-8
o-Xylene 95-47-6
m-Xylene 108-38-3
p-Xylene 106-42-3
1.2 This method is not applicable to the determination of styrene in
chlorinated drinking waters. The rapid oxidation rate of this
compound prevents the effective use of a dechlorinating agent as a
preservation technique for it.
-28-
-------
1.3 Single laboratory accuracy and precision data show that this
procedure is useful for the detection and measurement of
multi-component mixtures spiked into finished water and raw source
water at concentrations between 0.05 and 0.5 ug/L. The method
detection limit (MDL) (2) for each analyte is presented in Table 1
(1). Some laboratories may not be able to achieve these detection
limits since results are dependent upon instrument sensitivity and
matrix effects. Individual aromatic compounds can be measured at
concentrations up to 1500 ug/L« Determination of complex mixtures
containing partially resolved compounds may be hampered by
concentration differences larger than a factor of 10.
1.4 This method is recommended for use only by analysts experienced in
the measurement of purgeable organics at the low ug/L level or by
experienced technicians under the close supervision of a qualified
analyst.
2. SUMMARY OF METHOD
2.1 Highly volatile organic compounds with low water solubility are
extracted (purged) from a 5-mL sample by bubbling an inert gas
through the aqueous sample. Purged sample components are trapped
in a tube containing a suitable sorbent material. When purging is
complete, the sorbent tube is heated and backflushed with an inert
gas to desorb trapped sample components onto a gas chromatography
(GC) column. The gas chromatograph is temperature programmed to
separate the method analytes which are then detected with a
photoionization detector.
2.2 A second chromatographic column is described that can be used to
confirm GC identifications and measurements. Alternatively,
confimatory analyses may be performed by gas chromatography/mass
spectrometry (GC/MS) according to Method 524.1 if sufficient
material is present.
3. INTERFERENCES
3.1 Samples may be contaminated during shipment or storage by diffusion
of volatile organics through the sample bottle septum seal. Field
reagent blanks (Sect. 9.1.1) must be analyzed to determine if
contamination has occurred.
3.2 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 field reagent
blanks (Sect, 9.1.1) and laboratory reagent blanks (Sect. 9.1.2)
provide information about the presence of contaminants. When
-29-
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potential interfering peaxs are noted in laboratory reagent blanks,
the analyst should change the purge gas source and regenerate the
molecular sieve purge gas filter (Figure 1). Subtracting blank
values from sample results is not permitted.
3.3 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. For samples containing large
amounts of water soluble materials, suspended solids, high boiling
compounds or high levels of compounds being determined, it may be
necessary to wash out the purging device with a soap solution,
rinse it with distilled water, and then dry it in an oven at 105*C
between analyses.
3.4 Excess water will cause a negative baseline deflection in the
chromatogram. The method provides for a dry purge period to
prevent this problem.
4. SAFETY
4.1 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 (3-5) for the information of the analyst.
4.2 The following method analytes have been tentatively classified as
known or suspected human or mammalian carcinogens: benzene,
1,4-dichlorobenzene, hexachlorobutadiene, tetrachloroethene, and
trichloroethene. 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.
5. APPARATUS AND EQUIPMENT
5.1 SAMPLE CONTAINERS - 40-mL to 120-mL screw cap vials (Pierce #13075
or equivalent) each equipped with a PTFE-faced silicone septum
(Pierce #12722 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 in a 105°C
oven for one hour, then remove and allow to cool in an area known
to be free of organics.
-------
5.2 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.
5.2.1 The all glass purging device (Figure 1) must be designed to
accept 5-mL samples with a water column at least 3 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 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. ~"
5.2.2 The trap (Figure 2) must be at least 25 cm long and have an
inside diameter of at least 0,105 in. It is recommended
that 1.0 cm of methyl silicone coated packing be added at
the inlet end to prolong the life of the trap. Add a suffi-
cient amount of 2,6-diphenylene oxide polymer to fill the
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 minutes at 180'C with back-
flushing. 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.
5.2.3 The^desorber must be capable of rapidly heating the trap to
180*C. The trap should not be heated higher than 200*0 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. The
desorber design illustrated in Figure 2 meets these criteria.
5.2.4 The purge and trap system may be assembled as a separate
unit or be coupled to a gas chromatograph as illustrated in
Figures 3-6.
5.3 GAS CHROMATOGRA'PHY SYSTEM
5.3.1 The GC must be capable of temperature programming and should
be equipped with variable-constant differential flow
controllers so that the column flow rate will remain
constant throughout desorption and the temperature program.
5.3.2 Two gas chromatography columns are recommended. Column 1 is
a highly efficient column that provides outstanding
separations for a wide variety of organic compounds. Column
1 should be used as the primary analytical column unless
-------
routinely occurring analytes are not adequately resolved.
Column 2 is recommended for use as a confirmatory column
when GC/MS confirmation is not available. Retention times
for the listed analytes on the two columns are presented in
Table 1.
5.3.2.1 Column 1 - 1.5 to 2.5 m x 0.085 in ID #304 stainless
steel or glass, packed with 5% SP-1200 and 1.75%
Bentone 34 on Supelcoport (80/100 mesh) or
equivalent. The flow rate of the helium carrier gas
must be established at 30 mL/min. Two temperature
programs have been found to be useful and are
described in Table 1. Program A optimizes
separations for the early eluting analytes, while
Program B optimizes the separation for the later
eluting analytes. When not in use,amaintainathe
column at the upper temperature (90'C or IIO'C) of
the program. Condition new SP-1200/Bentone columns
with carrier gas flow at 120*C for several days
before connecting to the detector. Sample
chromatograms obtained with Column 1 are presented
in Figures 7 and 8.
5.3.2.2 Column 2 - 1.5 to 2.5 m long x 0..085 in ID # 304
stainless steel or glass, packed with 5%
l,2,3-tris(2-cyanoethoxy) propane on Chromosorb W
(60/80 mesh) or equivalent. The flow rate of the
helium carrier gas must be established at 30
mL/min. The column temperature must be programmed
to hold at 40°C for 2 min, increase to 100'C at
2"C/min, and hold at 100'C until all expected
compounds have eluted. A sample chromatogram
obtained with Column 2 is presented in Figure 9.
5.3.3 A high temperature photoionization detector equipped with
a 10.2 eV lamp is required (HNU Systems, Inc., Model
PI-51-02 or equivalent).
5.4 SYRINGE AND SYRINGE VALVES
5.4.1 Two 5-mL glass hypodermic syringes with Luer-Lok tip.
5.4.2 Three 2-way syringe valves with Luer ends.
5.4.3 One 25-uL micro syringe with a 2 in x 0.006 in ID, 22* bevel
needle (Hamilton #702N or equivalent).
5.4.4 Micro syringes - 10, 100 uL.
5.5 MISCELLANEOUS
5.5.1 Standard solution storage containers - 15-mL bottles with
PTFE-lined screw caps.
-32-
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6. REAGENT AND CONSUMABLE MATERIALS
6.1 TRAP PACKING MATERIALS
6.1.1 2,6-Diphenylene oxide polymer, 60/80 mesh, chromatographic
grade (Tenax GC or equivalent).
6.1.2 Methyl, silicone packing - OV-1 (3%) on Chromosorb-W, 60/80
mesh or equivalent.
6.2 COLUMN PACKING MATERIALS
6.2.1 5% SP-1200/1.75% Bentone 34 on 100/120 mesh Supelcoport or
equivalent.
6.2.2 5% l,2,3-tris(2-cyanoethoxy) propane on 60/80 mesh
Chromosorb W or equivalent.
6.3 REAGENTS
6.3.1 Methanol - demonstrated to be free of analytes.
6.3.2 Reagent water - water meeting specifications in Sect.
9.1.2. 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.
6.3.3 Hydrochloric acid (1+1) - Carefully add measured volume of
cone. HC1 to equal volume of reagent water.
6.4 STANDARD STOCK SOLUTIONS - These solutions may be purchased as
certified solutions or prepared from pure standard materials using
the following procedures:
6.4.1 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 and weigh to the nearest 0.1 mg.
6.4.2 Using a 100-vL syringe, 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.
6.4.3 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
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compound purity is certified at 96% or greater, the weight
can be used without correction to calculate the
concentration of the stock standard.
6.4.4 Store stock standard solutions at 4°C in 15-mL bottles
equipped with PTFE-lined screw caps. Methanol solutions ars
stable for at least four weeks when stored at 4°C.
6.5 SECONDARY DILUTION STANDARDS - Use standard stock solutions to
prepare secondary dilution standard solutions that contain the
analytes in methanol. The secondary dilution standards should be
prepared at concentrations that can be easily diluted to prepare
aqueous calibration solutions (Sect. 8.1) that will bracket the
working concentration range. Store the secondary dilution standard
solutions with minimal headspace and check frequently for signs of
deterioration or evaporation, especially just before preparing
calibration solutions from them. Secondary dilution standard
solutions must be replaced after one month.
7. SAMPLE COLLECTION, PRESERVATION, AND STORAGE
7.1 SAMPLE COLLECTION
7.1.1 Replicate field reagent blanks 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 empty sample bottles. Wherever a set of
samples is shipped and stored, it must be accompanied by
field reagent blanks.
7.1.2 Collect all samples in duplicate. Fill sample bottles to
overflowing. No air bubbles should pass through the sample
as the bottle is filled, or be trapped in the sample when
the bottle is sealed.
7.1.3 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 duplicate samples from the flowing stream.
7.1.4 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 duplicate sample
bottles from the 1-quart container.
7.2 SAMPLE PRESERVATION
7.2.1 Adjust the pH of the duplicate samples and the field reagent
blanks to <2 by carefully adding one drop of 1:1 HC1 for
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each 20 ml of sample volume. Seal the sample bottles,
PFTE-face down, and shake vigorously for one minute.
7.2.2 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 that they will be < 4°C on arrival
at the laboratory. . "~
7.3 SAMPLE STORAGE
7.3.1 Store samples and field reagent blanks together at 4*C until
analysis. The sample storage area must be free of organic
solvent vapors.
7.3.2 Analyze all samples within 14 days of collection. Samples
not analyzed within this period must be discarded and
replaced.
8. CALIBRATION AND STANDARDIZATION
8.1 CALIBRATION
8.1.1 A set of at least five calibration standards containing the
method analytes is needed. More than one set of calibration
standards may be required. One calibration standard should
contain each analyte at a concentration approaching but
greater than the method detection limit (Table 1) for that
compound; the other standards should contain analytes at
concentrations that define the range of the method.
8.1.2 To prepare a calibration standard, add an appropriate volume
of a secondary dilution standard solution to an aliquot of
reagent water in a volumetric container. Do not add less
than 20 uL of an alcoholic standard to the reagent water or
poor precision will result. Use a 25-uL microsyringe and
rapidly inject the alcoholic standard into the water.
Remove the needle as quickly as possible after injection.
Aqueous standards are not stable and should be discarded
after one hour unless preserved, sealed and stored as
described in Sect. 7.2.2.
8.1.3 Starting with the standard of lowest concentration, analyze
each calibration standard according to Sect. 10 and tabulate
peak height or area response 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.
8.1.4 The working calibration curve or calibration factor must be
verified on each working day by the measurement of one or
more calibration standards. 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 or use a single point calibration standard
as described in Sect. 8.1.5.
8.1.5 Single point calibration is a viable alternative to a
calibration curve. Prepare single point standards from the
secondary dilution standards in methanol. Tne single point
standards should be prepared at a concentration that
produces a response close (*20%) to that of the unknowns.
Do not use less than 20 uL of the secondary dilution
standard to produce a single point calibration standard in
reagent water.
8.1.6 As a second alternative to a calibration curve, internal
standard calibration techniques may be used. a,a,o-Tri-
fluorotoluene is recommended as in internal standard for
this method. The internal standard is added to the sample
just before purging. Check the validity of the internal
standard calibration factors daily by analyzing a
calibration standard.
8.2 INSTRUMENT PERFORMANCE - Check the performance of the entire
analytical system daily using data gathered from analyses of
reagent blanks, standards, duplicate samples, and the laboratory
control standard (Sect. 9.2.2).
8.2.1 All of the peaks contained in the standard chromatograms
must be sharp and symmetrical. Peak tailing significantly
in excess of that shown in the method chromatograms (Figures
7, 8, and 9) must be corrected. If only the compounds
eluting before ethylbenzene give random responses or
unusually wide peak widths, are poorly resolved, or are
missing, the problem is usually traceable to the
trap/desorber. If negative peaks appear early in the
chromatogram, increase the dry purge time to 5 min.
8.2.2 Check the precision between laboratory replicates. A
properly operating system should perform with an average
relative standard deviation of less than 10%. Poor
precision is generally traceable to pneumatic leaks,
especially around the sample purger or to an improperly
' adjusted lamp intensity power. Monitor the retention times
for each method analyte using data generated from
calibration standards and the laboratory control standard.
-36-
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If individual retention times vary by more than 10% over an
8-h period or do not fall within 10% of an established norm,
the source of retention data variance must be corrected
before acceptable data can be generated.
9. QUALITY CONTROL
9.1 MONITORING FOR INTERFERENCES
9.1.1 Field Reagent Blanks - A field reagent blank (Sect. 7.1.1)
is a sealed bottle of reagent water that accompanies a set
of sample bottles from the laboratory to a sampling site and
back. Analyze a field reagent blank along with each sample
set. If the field reagent blank contains a reportable level
of any analyte, analyze a laboratory reagent blank as
described in Sect. 9.1.2. If the contamination is not
detected in the laboratory reagent blank, the sampling or
transportation practices have caused the contamination. In
this case, discard all samples in the set and resample the
site.
9.1.2 Laboratory Reagent Blanks - A laboratory reagent blank is a
5-mL aliquot of reagent water analyzed as if it were a
sample. Analyze a laboratory reagent blank each time fresh
reagent water is prepared and as. necessary to identify
sources of contamination. The laboratory reagent blank
. should be below the method detection limit or represent less
than 10% interference for those compounds that are monitored.
9.2 ASSESSING ACCURACY
9.2.1 At least quarterly, analyze a quality control check sample
obtained from the U.S. Environmental Protection Agency,
Environmental Monitoring and Support Laboratory (EMSL),
Quality Assurance Branch, Cincinnati. If measured analyte
concentrations are not within acceptance limits provided
with the sample, check the entire analytical procedure to
locate and correct the problem source.
9.2.2 After every 10 samples, and preferably in the middle of each
day, analyze a laboratory control standard. Calibration
standards may not be used for accuracy assessments and the
laboratory control standard may not be used for calibration
of the analytical system.
9.2.2.1 Laboratory Control Standard Concentrate - If
internally prepared laboratory control standards are
used to provide the routine assessment of accuracy,
they should be prepared from a separate set of stock
standards. From stock standards prepared as
described in Sect. 6.4, add 500 uL of each stock
standard to methanol in a 10-mL volumetric flask and
adjust to volume.
-37.
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9.2.2.2 Laboratory Control Standard - Add 20 yl_ of the
control standard concentrate to 100 ml of reagent
water in a 100-mL volumetric flask and mix well.
9.2.2.3 Analyze a 5-mL aliquot of the laboratory control
standard as described in Sect. 10. For each analyte
in the laboratory control standard, calculate the
percent recovery (P^) with the equation:
P.
where S-j * the analytical result from the
laboratory control standard, in ug/L; and
TT * the known concentration of the spike,
in
9.2.3 At least annually, the laboratory should participate in
formal performance evaluation studies, where solutions of
unknown concentrations are analyzed and the performance of
all participants is compared.
9.3 ASSESSING PRECISION
9.3.1 Precision assessments for this method are based upon the
analysis of field duplicates (Sect. 7.1). Analyze both
sample bottles for at least 10% of all samples. To the
extent practical, the samples for duplication should contain
reportable levels of most of the analytes.
9.3.2 For each analyte in each duplicate pair, calculate the
relative range (RR-j) with the equation:
RR. - Ri
' Xi
where Ri = the absolute difference between the
duplicate measurements X]_ and X£. in
ug/L
X-j a the average concentration found
([Xi + X2]/2), in ug/L.
9.3.3 Individual relative range measurements are pooled to
determine average relative range or to develop an expression
of relative range as a function of concentration.
10. PROCEDURE
10.1 INITIAL CONDITIONS - 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.
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10.2 SAMPLE INTRODUCTION AND PURGING
10.2.1 Remove the plungers from two 5-mL syringes and attach a
closed syringe valve to each. Warm the sample 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 syringe, and compress the sample. Open the
syringe valve and vent any residual air while adjusting the
sample volume to 5.0 ml. If applicable, add 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.
10.2.2 Attach the sample syringe valve to the syringe valve on the
purging device. Open the sample syringe valve and inject
the sample into the purging chamber. Close both valves and
initiate purging. Purge the sample for 12.0 * 0.1 min at
ambient temperature (Figure 3).
10.3 TRAP DRY AND SAMPLE DESORPTION - After the 12-min purge, adjust the
purge and trap system to the dry purge position (Figure 4) for four
min. Empty the purging device using the sample syringe and wash
the chamber with two 5-mL flushes.of reagent water. After the
4-min dry purge, attach the trap to the chromatograph, adjust the
purge and trap system to the desorb mode (Figure 5) and initiate
the temperature program sequence of the gas chromatograph.
Introduce the trapped materials to the GC column by rapidly heating
the trap to 180'C while backflushing the trap with an inert gas
between 20 and 60 mL/min for 4.0 * 0.1 min. The transfer is
complete after approximately four min and the column is then
rapidly heated to the initial operating temperature for analysis.
10.4 TRAP RECONDITIONING - After desorbing the sample for four min,
recondition the trap by returning the purge and trap system to the
purge mode. Wait 15 s, then close the syringe valve on the purging
device to begin gas'flow through the trap. Maintain the trap
temperature at 180*C. After approximately 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.
11. CALCULATIONS
11.1 Identify each organohalide in the sample chromatogram by comparing
the retention time of the suspect peak to retention times generated
by the calibration standards and the laboratory control standard
(Sect. 8.2.2).
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11.2 Determine the concentration of the unknowns 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 Peak height sample Concentration of
unknown (ug/L) = Peak height stanaard x standard (ug/L)
11.3 Report the results for the unknown samples in ug/L. Round off the
results to the nearest 0.1 ug/L or two significant figures.
12. ACCURACY AND PRECISION
12.1 Single laboratory (EMSL-Cincinnati) accuracy and precision for most
of the analytes spiked in Ohio River water and chlorinated drinking
water are presented in Table 2.(6)
12.2 This method was tested by 20 laboratories using drinking water
spiked with various method analytes at six concentrations between
2.2 and 600 ug/L. Single operator precision, overall precision,
and method accuracy were found to be directly related to the
concentration of the analyte. Linear equations to describe these
relationships are presented in Table 3 (7).
12.3 Multilaboratory studies have been conducted by the Quality
Assurance Branch of EMSL-Cincinnati to evaluate the performance of
various laboratories. Accuracy and precision data applicable to
this method for several purgeable aromatics in reagent water are
presented in Table 4 (8).
13. REFERENCES
1. "The Analysis of Aromatic Chemicals in Water by the Purge and Trap
Method, Method 503.1," U.S. Environmental Protection Agency,
Environmental Monitoring and Support Laboratory, Cincinnati, Ohio
45268, April, 1981.
2. Glaser, J.A., O.L. Foerst, G.D. McKee, S.A. Quave, and W.L. Budde,
"Trace Analyses for Wastewaters," Environ. Sci. Techno!., 15, 1426,
1981.
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. Bellar, T.A., O.J. Lichtenberg, "The Determination of Volatile
Aromatic Compounds in Drinking Water and Raw Source Water,"
unpublished report, U.S. Environmental Protection Agency,
Environmental Monitoring and Support Laboratory, Cincinnati, Ohio
1982.
7. "EPA Method Validation Study 24, Method 602 (Purgeable Aromatics),"
U.S. Environmental Protection Agency, Environmental Monitoring and
Support Laboratory, Cincinnati, Ohio 45268.
8. "Analytical Methods and Monitoring Issues Associated with Volatile
Organics in Drinking Water," U.S. Environmental Protection Agency,
Office of Drinking Water, Washington, D.C., June 1984.
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Table 1. RETENTION TIMES AND METHOD DETECTION LIMITS (MDL)
FOR METHOD ANALYTES
Retention Time
(sec)
Column 1
Analyte
Benzene
Trichloroethene
a,a,a-Trifluoroto1uene(a)
Toluene
Tetrachloroethene
Ethyl benzene
l-Chlorocyclohexene(b)
p-Xylene
Chlorobenzene
m-Xylene
o-Xyl ene
Isopropyl benzene
Styrene
1 , 4-8romof 1 uorobenzene{ b )
n-P ropy! benzene
tert-Butyl benzene
2-Chlorotoluene
4-Chlorotoluene
Bromobenzene
sec-Butyl benzene
1, 3, 5-Trimethyl benzene
4-Isopropyltoluene
1, 2, 4-Trimethyl benzene
1,4-Oichlorobenzene
1,3-Oi chlorobenzene
Cycl opropy 1 benzene( b )
n-Butyl benzene
2,3-Benzofuran(b)
1 ,2-Oi ch 1 orobenzene
Hexach 1 orobutadiene
1, 2, 4-Tri chlorobenzene
Naphthalene
1, 2, 3-Trichl orobenzene
Program
A
199
223
275
340
360
491
518
518
542
542
574
595
644
664
681
786
804
804
804
829
851
909
909
999
1082
1082
1082
1283
1528
2035
2690
4280
4526
Program
B
199
231
296
384
406
606
637
653
689
689
738
768
834
852
879
975
985
990
999
1027
1043
1090
1090
1152
1211
1211
1211
1320
1425
1650
1928
2545
2631
Column 2
165
142
168
255
168
375
345
403
481
403
518
455
690
740
518
595
681
__
807
595
612
681
750
975
901
765
1460
1161
1011
1535
2298
1820
MDL
ug/i
0.02
0.01
0.02
0.02
0.01
0.002
0.008
0.002
0.004
0.004
0.004
0.005
0.008
0.009
0.006
0.008
0.002
0.02
0.003
0.009
0.006
0.006 .
0.006
0.02
0.03
0.02
0=02
0.03
0.04
0.03
(a) » Recommended internal standard (Sect. 8.1.6).
(b) = Analyte not included in proposed monitoring requirement,
-42 -
-------
Table 1. (CONTINUED)
Column I conditions: Supelcoport (100/120 mesh) coated with 5%
SP-1200/1.75% Bentone 34 packed in a 6 ft x 0.085 in ID stainless steel or
glass column with helium^carrier at 30 mL/min flowrate. Column temperature
for Program A held at 50*C for 2 min then programmed at 6*C/min to 90*C for
a final hold. Column temperature for Program B held at 50*C for 2 min then
programmed at 3*C/min to 110'C for a final hold.
Column 2 conditions: Chromosorb W(60/80 mesh) coated with 5%
1,2,3-tris(2-cyanoethoxy)propane packed in a 6 ft x 0.085 in ID stainless
steel or glass column with hejium carrier gas at 30 mL/min flow rate.
Column temperature held at 40°C for 2 min then programmed at 2*C/min to
100'C for a final hold.
-43-
-------
Table 2. SINGLE LABORATORY ACCURACY AMD PRECISION FOR
AROMATIC AND UiNSATURATEQ ANALYTES IN CHLORINATED
DRINKING WATER AND RAU SOURCE WATER
Analyte
Benzene
Bromobenzene
n-Butyl benzene
sec-Butyl benzene
tert-Butyl benzene
Chlorobenzene
l-Chlorocyclohexene(b)
4-Chlorotoluene
1,2-Di Chlorobenzene
1 , 3-Oi ch 1 orobenzene
1,4-Oi Chlorobenzene
Ethyl benzene
Hexach 1 orobutad i ene
Isopropyl benzene
Naphthalene
n-Propyl benzene
Tetrachloroethene
Toluene
1,2, 3-Tri ch 1 orobenzene
1, 2, 4-Tri Chlorobenzene
Trichloroethene
a,a,a-Trichlorotoluene(c)
I, 2, 4-Trimethyl benzene
1,3, 5-Trimethyl benzene
m-Xylene
o-Xylene
p-Xylene
Matrix
Type (a)
A,S
A,B
A
A
A
A,B
A,B
A,B
A,B
A,B
A.B
A
A
A
A,B
A
A,B
A,B
A,B
A,B
A,B
A,3
A
A
A
A
A
Spike
Level
ug/L
0.40
0.50
0.40
0.40
0.40
0.50
0.50
0.50
0.50
0.50
0.50
0.40
0.50
0.40
0.50
0.40
0.50
0.40
0.50
0.50
0.50
0.50
0.40
0.50
0.40
0.40
0.40
Samples
Analyzed
13
19
7
7
7
19
19
17
18
19
19
7
10
7
16
7
19
13
18
18
19
18
7
10
7
7
7
Average Relative
Recovery Standard
(%) Deviation (%)
100
93
78
80
88
96
89
91
92
91
95
93
74
88
92
83
97 '
94
35
36
97
38
75
92
90
90
85
2.8
6.2
15.7
11.0
8.7
5.8
7.1
5.0
7.1
8.5
6.4
8.5
16.8
8.7
14.8
9,3
7.8
6.6
10.4
10.1
6.8
9.7
8.7
8.7
7.7
7.2
8.7
(a) = Matrix A is drinking water. Matrix B is raw source water.
(b) » Analyte not included in proposed monitoring requirement.
(c) » Recommended internal standard (Sect. 8.1.6).
-44-
-------
Table 3. SINGLE ANALYST PRECISION, OVERALL PRECISION,
AND ACCURACY FOR PURGEABLE ARQMATICS IN DRINKING WATER
Analyte
Benzene
Chi orobenzene
1 ,2-Di chl orobenzene
1 , 3-Dichl orobenzene
1 , 4-Oi ch 1 orobenzene
Ethyl benzene
Toluene
Single Analyst
Precision
(uq/L)
0.111 - 0.06
0.101 * 0.12
0.101 + 0.42
0.087 + 0.33
0.091 + 0.39
0.101 + 0.18
0.107 + 0.18
Overall
Precision
(uq/L)
0.221 + 1.11
0.161 + 0.36
0.187 + 0.28
0.151 + 0.33
0.151 + 0.39
0.201 + 0.68
0.211 + 0.16
Accuracy as
Mean Recovery (I)
(uq/L)
0.97C + 0.85
0.94C + 0.12
0.91C + 0.44
0.93C + 0.21
0.91C + 0.26
0.97C + 0.41
0.94C + 0.17
T * mean recovery (ug/L)
C a true value for the concentration (ug/L)
-45-
-------
Table 4. ACCURACY AND PRECISION DATA FOR PURGEABLE AROMATICS
FROM MULTILABORATORY PERFORMANCE EVALUATION STUDIES
Analyte (
Benzene
Chlorobenzene
1,2-Dichlorobenzene -
1 ,4-Di chl orobenzene
1,2,4-Trichlorobenzene
Spike
Level Number of
[ug/L) Laboratories
94.1
47.0
18.8
8.10
41.4
27,6
13.8
5.52
96.9
19.4
68.5
13.7
80.8
6.7
9
10
8
11
5
7
6
8
5
4
5
5
6
6
Average
Measured
Concen-
trations
Ug/U
91.9
47.0
18.7
6.22
39.8
27.1
14.3
5.65
72.9
16-. 5
62.5
14.6
77.6
8.46
Relative
Standard
Deviation
(%)
18.6
11.8
16.4
40.8
6.20
12.1
6.73
25.3
31.6
18.8
22.8
29.1
14.3
30.7
Average
Recovery
(%}
98
100
100
88
96
98
104
102
75
85
91
107
96
126
.46-
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-------
METHOD 504. MEASUREMENT OF 1,2-DIBROMOETHANE (EDB) AND
l,2-OIBROMO-3-CHLOROPROPANE (DBCP) IN DRINKING 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 compounds in finished drinking water and unfinished
groundwater:
Analyte CAS No.
1,2-Oibromoethane 106-93-4
1,2-Oi bromo-3-Ch1oropropane 96-12-8
1.2 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
(4) and provide qualitative confirmation of results by Gas
Chromatography/Mass Spectrometry (GC/MS) (5).
1.3 The experimentally determined method detection limits (MDL) (6) for
EDB and DBCP were calculated to be 0.01 ug/L. The method has been
shown to be useful for these" analytes over a concentration range
from approximately 0.03 to 200 ug/L. Actual detection limits ara
highly dependent upon the characteristics of the gas chrcmato-
graphic system used.
2. SUMMARY OF METHOD
2.1 Thirty-five mL of sample are extracted with 2 mL of hexane. Two uL
of the extract are then injected into a gas chromatograph equipped
with a linearized electron capture detector for separation and
analysis. Aqueous calibration standards are extracted and analyzed
in an identical manner as the samples in order to compensate for
possible extraction losses.
2.2 The extraction, and analysis time is 30 to 50 minutes per sample
depending upon the analytical conditions chosen. (See Table 1 and
Figure 1.)
2.3 Confirmatory evidence can be obtained using a dissimilar column
(see Table 1). When component concentrations are sufficiently high
(> 50 ug/L), Method 524.1 (7) may be employed for improved speci-
ficity.
3. INTERFERENCES
3.1 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
sample blanks (7.1.1). Whenever an interference is noted in the
sample blank, the analyst should reanalyze the extracting solvent.
Low level interferences generally can be removed by distillation or
column chromatography (3); however, it is generally more economical
to obtain a new source solvent. Interference-free solvent is
defined as a solvent containing less than 0.1 ug/L individual
analyte interference. Protect interference-free solvents by
storing in an area known to be free of organochlorine solvents.
3.2 Several instances of accidental sample contamination have been
attributed to diffusion of volatile organics through the septum
seal into the sample bottle during shipment and storage. The
sample blank (7.1.1) is used to monitor for this problem.
3.3 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.
3.4 EOB at low concentrations may be masked by very high levels of
dlbromochloromethane (DBCM), a common chlorinated drinking water
contaminant, when using the confirmation column (Sect. 5.8.2.2).
4. SAFETY
4.1 The toxicity and 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 (8-10) for the information of the analyst.
4.2 ED8 and D8CP 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 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.
5. APPARATUS AND EQUIPMENT
- 5.1 SAMPLE CONTAINERS - 40-mL screw cap vials (Pierce #13075 or
equivalent) each equipped with a PTFE-faced silicone septum (Pierce
#12722 or equivalent). Prior to use, wash vials and septa with
detergent and rinse with tap and distilled water. Allowothe 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.
-57.
-------
5.2 VIALS, auto sampler, screw cap with septa, 1.8 ml, Varian
#96-000099-00 or equivalent.
5.3 MICRO SYRINGES - 10 and 100 uL.
5.4 MICRO SYRINGE - 25 uL with a 2-inch by 0.006-inch needle - Hamilton
702N or equivalent.
5.5 PIPETTES - 2.0 and 5.0 mL transfer.
5.6 VOLUMETRIC FLASKS - 10 and 100 mL, glass stoppered
5.7 STANDARD SOLUTION STORAGE CONTAINERS - 15-mL bottles with
PTFE-lined screw caps.
5.8 GAS CHROMATOGRAPHY SYSTEM
5.8.1 The GC must be capable of temperature programming and should
be equipped with a linearized electron capture detector and a
capillary column splitless injector.
5.8.2 Two gas chromatography columns are recommended. Column A is
a highly efficient column that provides separations for EDB
and D8CP without interferences from trihalomethanes (Sect.
3.4). 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 available. Retention
times for EDB and D8CP on these columns are presented in
Table 1.
5.8.2.1 Column A - 0.32 mm ID x 30M long fused silica
capillary with dimethyl silicone mixed phase
(Durawax-OX3, 0.25 urn film, or equivalent). The
linear velocity of the helium carrier gas is
established at 25 cm/sec. The column temperature is
programmed to hold at 40*C for 4 min, to increase to
190 C at 8*C/min, and hold at 190°C for 25 min or
until all expected compounds have eluted. Injector
temperature: 200*C. Detector temperature: 290"C.
(See Figure 1 for a sample chromatogram and Table 1
for retention data).
5.8.2.2 Column 8 (confirmation column) - 0.32mm ID x 30M
long fused silica capillary with methyl polysiloxane
phase (DB-1, 0.25 ym film, or equivalent). The
linear velocity of the helium carrier gas is
established at 25 cm/sec. The column temperature is
proarammed to hold at 40°C for 4 min, to increase to
270*C at 10'C/minute, and hold at 270°C for 10 min
or until all expected compounds have eluted.
Injector temperature: 200°C. Detector tempera-
ture: 290"C. (See Table 1 for retention data).
-58-
-------
6. REAGENTS AND CONSUMABLE MATERIALS
6.1 REAGENTS
6.1.1 Hexane extraction solvent - UV Grade, Burdick and Jackson
#216 or equivalent.
6.1.2 Methyl alcohol - ACS Reagent Grade, demonstrated to be free
of analytes.
6.1.3 Sodium chloride, Nad - 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 minutes. Place in a bottle and cap.
6.2 STANDARD MATERIALS
6.2.1 1,2-Oibromoethane - 99%, available from Aldrich Chemical
Company.
6.2.2 l,2-Dibromo-3-chloropropane - 99.4%, available from AMVAC
Chemical Corporation, Los Angeles, California.
6.3 REAGENT WATER - Reagent water is defined as water free of inter-
ference when employed in the procedure described herein.
6.3.1 Reagent water can be generated by passing tap water through
a filter bed containing activated carbon. Change the
activated carbon whenever the criteria in Sect. 9.1.2 cannot
be met.
6.3.2 A Millipore Super-Q Water System or its equivalent may be
used to generate deionized reagent water.
6.3.3 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/minute for 1 hour. While still hot, transfer the
water to a narrow mouth screw cap bottle with a Teflon seal.
6.3.4 Test reagent water each day it is used by analyzing it
according to Sect. 10.
6.4 STANDARD STOCK SOLUTIONS - These solutions may be purchased as
certified solutions or prepared from pure standard materials using
the following procedures:
6.4.1 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.
-------
6.4.2 Use a 100-uL syringe and immediately add two or more drops
of standard material to the flask. 3e sure that the
standard material falls directly into the alcohol without
contacting the neck of the flask.
6.4.3 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.
6.4.4 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.
6.5 SECONDARY DILUTION STANDARDS Use standard stock solutions to
prepare secondary dilution standard solutions that contain both
analytes in methanol. The secondary dilution standards should be
prepared at concentrations that can be easily diluted to prepare
aqueous calibration standards (Sect. 8.1.1) that will bracket the
working concentration range. Store the secondary 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. 6.4.4 also applies to secondary
dilution standard solutions.
7. SAMPLE COLLECTION. PRESERVATION, AND STORAGE
7.1 SAMPLE COLLECTION
7.1.1 Replicate field blanks 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 field
blanks.
7.1.2 Collect all samples in duplicate. Fill sample bottles to
overflowing. No air bubbles should pass through the sample
as the bottle is filled, or be trapped in the sample when
the bottle is sealed.
7.1.3 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 duplicate samples from the flowing stream.
7.1.4 When sampling from a well, fill a wide-mouth bottle or
.60-
-------
beaker with sample, and carefully fill duplicate 40-mL
sample bottles.
7.2 SAMPLE PRESERVATION
7.2.1 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 suffi-
cient ice to insure that they will be at 4*C on arrival at
the laboratory.
7.2.2 The addition of sodium thiosulfate as a dechlorinating agent
and/or acidification to pH 2 with 1:1 HC1, common preserva-
tion procedures for purgeable compounds, have been shown to
have no effect on ED8 and DBCP and, therefore, their use is
not recommended for samples to be analyzed for these
analytes.
7.3 SAMPLE STORAGE
7.3.1 Store samples and field blanks together at 4*C until
analysis. The sample storage area must be free of organic
solvent vapors.
7.3.2 Analyze all samples within 28 days of collection. Samples
not analyzed within this period must be discarded and
replaced.
8. CALIBRATION AND STANDARDIZATION
8.1 CALIBRATION
8.1.1 At least three calibration standards are needed. One should
contain EDB and OBCP at a concentration near to but greater
than the method detection limit (Table 1) for each compound;
the other two should be at concentrations that bracket the
range expected in samples. For example, if the MDL is
0.01 ug/L, and a sample expected to contain approximately
0.10 ug/L is to be analyzed, aqueous standards should be
prepared at concentrations of 0.02 ug/L, 0.10 ug/L, and
0.20 ug/L.
8.1.2 To prepare a calibration standard, add an appropriate volume
of a secondary dilution standard solution to an aliquot of
reagent water in a volumetric flask. Do not add less than
20 uL of an alcoholic standard to the reagent water or poor
precision will result. Use a 25-uL 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
-61-
-------
fresh daily unless sealed and stored without headspace as
described in Sect. 7.
8.1.3 Starting with the standard of lowest concentration, analyze
each calibration standard according to Sect. 10 and tabulate
peak height or area response 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.
8.1.4 The working calibration curve or calibration factor must be
verified on each working day by the measurement of one or
more calibration standards. If the response for an analyte
varies from the predicted response by more than ±15%, the
test must be repeated using a fresh calibration standard.
If the results still do not agree, generate a new calibra-
tion curve or use a single point calibration standard as
described in Sect. 8.1.5.
8.1.5 Single point calibration is a viable alternative to a
calibration curve. Prepare single point standards from the
secondary dilution standard solutions. The single point
calibration standard should be prepared at a concentration
that produces a response close (±20%) to that of the
unknowns. Do not use less than 20 uL of the secondary
dilution standard solution to produce a single point
calibration standard in reagent water.
8.2 INSTRUMENT PERFORMANCE - Check the performance of the entire
analytical system daily using data gathered from analyses of reagent
blanks, standards, duplicate samples, and the laboratory control
standard (Sect. 9.2.2).
8.2.1 Peak tailing significantly in excess of that shown in the
method chromatogram must be corrected. Tailing problems are
generally traceable to active sites on the GC column or the
detector operation.
8.2.2 Check the precision between replicate analyses. A properly
operating system should perform with an average relative
standard deviation of less than 10%. Poor precision is
generally traceable to pneumatic leaks, especially at the
injection port.
9. QUALITY CONTROL
9.1 MONITORING FOR INTERFERENCES
9.1.1 Field Blanks - A field blank is a sealed bottle of reagent
water that accompanies a set of sample bottles from the
-62.
-------
laboratory to a sampling site and back. Analyze a field
blank along with each sample set (Sect. 7.1.1). If the
field blank contains a reportable level of EDS or D8CP,
analyze a laboratory reagent blank as described in Sect.
9.1.2. If the contamination is not detected in the
laboratory reagent blank, the sampling or transportation
practices have caused the contamination. In this case,
discard all samples in the set and resample the site.
9.1.2 Laboratory Reagent Blanks - A laboratory reagent blank is a
35-mL aliquot of reagent water analyzed as if 1t were a
sample. Analyze a laboratory reagent blank each time fresh
reagent water is prepared and as necessary to identify
sources of contamination. The laboratory reagent blank
should contain less than 0.01 ug/L response of each analyte.
9.2 ASSESSING ACCURACY
9.2.1 Each quarter, it is essential that the laboratory analyze
quality control check standards for each contaminant. If
the criteria established by USEPA and provided with the QC
standards are not met, corrective action needs to be taken
and documented.
9.2.2 After every 10 samples, and preferably in the middle of each
day, analyze a laboratory control standard. Calibration
standards may not be used for accuracy assessments and the
laboratory control standard may not be used for calibration
of the analytical system.
9.2.2.1 Laboratory Control Standard Concentrate - If
internally prepared laboratory control standards
are used to provide the routine assessment of
accuracy, they should be prepared from a separate
set of stock standards. From stock standards
prepared as described in Sect. 6.4, add a suffi-
cient volume of each stock standard to methane1 in
a 10-mL volumetric flask to yield a concentration
of 2.5 ug/mL and adjust to volume.
9.2.2.2 Laboratory Control Standard (0.5 ug/L) - Add 20 vL
of the control standard concentrate to 100 mL of
reagent water in a 100-mL volumetric flask.
9.2.2.3 Analyze a 35-mL aliquot of the laboratory control
standard as described in Sect. 10. For each
analyte in the laboratory control standard,
calculate the percent recovery (P^) with the
equation:
100 S.
-------
where S-j = the analytical result from the
laboratory control standard, in ug/L;
and
T-j = the known concentration of the spike,
in ug/L.
9.2.3 It is essential that the laboratory analyze an unknown
performance evaluation sample (when available) once per year
for all regulated contaminants measured. Results need to be
within acceptance limits established by USEPA for each
analyte.
9.3 ASSESSING PRECISION
' 9.3.1 Precision assessments for this method are based upon the
analysis of field duplicates (Sect. 7.1.2). Analyze both
sample bottles for at least 10% of all samples. To the
extent practical, the samples for duplication should contain
reportable levels of the analytes.
9.3.2 For each analyte in each duplicate pair, calculate the
relative range (RR-j) with the equation:
where R^ = the absolute difference between the duplicate
measurements X]_ and Xj, in
X-j = the average concentration found
(C*i * X2]/2), in ug/L.
9.3.3 Individual relative range measurements are pooled to deter-
mine the average relative range or to develop an expression
of relative range as a function of concentration.
10. PROCEDURE
10.1 SAMPLE PREPARATION
10.1.1 Remove samples and standards from storage and allow them to
reach room temperature,
10.1.2 For samples and field blanks, contained in 40-mL bottles,
remove the container cap. Discard a 5-mL volume using a
5-mL transfer pipette. Replace the container cap and weigh
the container with contents to the nearest O.lg and record
this weight for subsequent sample volume determination, (see
Sect. 10.3 for continuation of weighing and calculation of
true volume) .
-64-
-------
10.1.3 For calibration standards, QC check standards and reagent
blank, measure a 35-mL volume using a 50-mL graduated
cylinder and transfer it to a 40-mL sample container.
10.2 MICROEXTRACTION AND ANALYSIS
10.2.1 Remove the container cap and add 7g NaCl (Sect. 6.1.3) to
the sample.
10.2.2 Recap the sample container and dissolve the NaCl by shaking
by hand for about 20 sec.
10.2.3 Remove the cap and, using a transfer pipette, add 2.0 ml of
hexane. Recap and shake vigorously by hand for 1 min.
Allow the water and hexane phases to separate. (If stored
at this stage, keep the container upside down.)
10.2.4 Remove the cap and carefully transfer 0.5 ml of the hexane
layer into an autosampler using a disposable glass pipette.
10.2.5 Transfer the remaining hexane phase, being careful not to
include any of the water phase, into^a second autosampler
vial. Reserve this second vial at 4*C for a reanalysis if
necessary.
10.2.6- Transfer the first sampTe vial to an autosampler set up to
inject 2.0 uL portions into the gas chromatograph for
analysis. Alternately, 2 uL portions of samples, blanks
and standards may be manually injected, although an auto-
sampler is strongly recommended.
10.3 DETERMINATION OF SAMPLE VOLUME
10.3.1 For samples and field blanks, remove the cap from the
sample container.
10.3.2 Discard the remaining sample/hexane mixture. Shake off the
remaining few drops using short, brisk wrist movements.
10.3.3 Reweigh the empty container with original cap and calculate
the net weight of sample by difference to the nearest
0.1 g. This net weight is equivalent to the volume of
water (in ml) extracted. (Sect. 11.3)
11. CALCULATIONS
11.1 Identify EDB and DBCP in the sample chromatogram by comparing the
retention time of the suspect peak to retention times generated by
the calibration standards and the laboratory control standard.
-------
11.2 Use the calibration curve or calibration factor (Sect. 3.1.3) to
directly calculate the uncorrected concentration (C-j) of each
analyte in the sample (e.g., calibration factor x response).
11.3 Calculate the sample volume (Vs) as equal to the net sample
weight:
Vs * gross weight (Sect. 10.1.2) - bottle tare (Sect. 10.3.3).
11.4 Calculate the corrected sample concentration as:
Concentration, ug/L = C^ X |i
11.5 Report the results for the unknown samples in ug/L. Round off the
results to the nearest 0.1 ug/L or two significant figures.
12. ACCURACY AND PRECISION
12.1 Single laboratory (EMSL-Cincinnati) accuracy and precision at
several concentrations in tap water are presented in Table 2. (11)
The method detection limits are presented in Table 1.
12.2 In a preservation study extending over a. 4-week period, the average
percent recoveries and relative standard deviations presented in
Table 3 were observed for reagent water (acidified), tap water and
groundwater. The results for acidified and non-acidified samples
were not significantly different.
13. 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 "Identifiction
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. "Handbook for Analytical Quality Control in Water and Wastewater
Laboratories," Analytical Quality Control Laboratory, National
Environmental Research Center, Cincinnati, Ohio, June 1972.
5. Budde, W.L., J.W. Eichelberger, "Organic Analyses Using Gas
Chromatography-Mass Spectrometry," Ann Arbor Science, Ann Arbor,
Michigan 1979.
6. Glaser, J.A. et al., "Trace Analyses for Wastewaters," Environmental
Science and Technology, 15, 1426 (1981).
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7. "Methods for the Determination of Organic Compounds in Finished Drinking
Water and Raw Source Water," Environmental Monitoring and Support
Laboratory, Cincinnati, Ohio, June 1985.
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.
11. Winfield, T., et al. "Analysis of Organohalide Pesticides in Drinking
Water by Microextraction and Gas Chromatography." In preparation.
-67-
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Table 1. CHROMATOGRAPHIC CONDITIONS AND METHOD DETECTION
LIMITS FOR 1,2-DIBROMOETHANE (EDB) AND
1,2-DIBROMO-3-CHLOROPROPANE (D8CP)
Analyte
EDB
DBCP
Retention Time, Min
Column AColumn 8
9.5
17.3
8.9
15.0
MDL, ug/L
0.01
0.01
Column A conditions: Durawax-OX 3 (0.25 um film thickness) in a 30 m long x
0.32 mm ID fused silica capillary column with helium carrier gas at
25 cm/sec. Column temperature held isothermal at 40*C for 4 min, then
programmed at 8°C/min to 180'C for final hold.
Column B conditions: DB-1 (0.25 urn film thickness) in a 30 m long x 0.32 mm
ID fused silica capillary column with helium carrier gas at 25 cm/sec.
Column temperature held isothermal at 40*C for 4 min, then programmed at
10"C/min to 270*C for final hold.
Table 2. SINGLE LABORATORY ACCURACY AND PRECISION
FOR EDB AND DBCP IN TAP WATER
.
Analyte
1,2-Oibromoethane
1 ,2-Di bromo-3-chl oropropane
-
Number
of
Samples
7
7
7
7
7
7
Spike
Level
(ug/L)
0.03
0.24
50.0
0.03
0.24
50.0
Average
Accuracy
(%)
114
98
95
90
102
94
Relative
Standard
Deviation
(%)
9.5
11.8
4.7
11.4
8.3
4.8
S68-,
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Table 3. ACCURACY AND PRECISION AT 2.0 ug/L
OVER A 4-WEEK STUDY PERIOD
Analyte
EDB
DBCP
Matrix^
RW-A
GW
GW-A
TW
TW-A
RW-A
GW
GW-A
TW
TW-A
Number
of Samples
16
15
16
16
16
16
16
16
16
16
Average
Accuracy
(% Recovery)
104
101
96
93
93
105
105
101
95
94
Relative
Std. Dev.
(X)
4.7
2.5
4.7
6.3.
6.1
8.2
6.2
8.4
10.1
6.9
^Matrix Identities
RW-A » Reagent water at pH 2
GW » Groundwater, ambient pH
GW-A » Groundwater at pH 2
TW a Tap water, ambient pH
TW-A » Tap water at pH 2.
-------
o
s
>>
-«»» x
a
o
U I 3
X O
p 1. O
*. 3
M UJ UJ Z
34/1 Z UJ
U.< 5^ S
S O
Ck, O
o
-J U.
-------
METHOD 524.1. VOLATILE ORGANIC COMPOUNDS IN WATER BY
PURGE AND TRAP GAS CHROMATOGRAPHY/MASS SPECTROMETRY
1. SCOPE AND APPLICATION
1.1 This method is applicable for the determination of various volatile
organic compounds in finished drinking water, raw source water, or
drinking water in any treatment stage. (1) The method may be used
to calculate total trihalomethane (TTHM) concentrations as defined
and required in 40 CFR Part 141.30 if a reducing agent is added as
described in Sect. 7.1.2. The following compounds can be
determined by this method:
Chemical Abstract Services
Analyte Registry Number
Benzene 71-43-2
Bromobenzene 108-86-1
Bromochloromethane 74-97-5
Bromodichloromethane 75-27-4
Bromoform 75-25-2
Bromomethane 74-83-9
n-Butylbenzene* " 104-51-8
sec-Butyl benzene 135-98-8
tert-Butylbenzene 98-06-6
Carbon tetrachloride 56-23-5
Chlorobenzene 108-90-7
Chloroethane 75-00-3
Chloroform 67-66-3
bis-2-Chloroisopropyl ether 108-60-1
Chloromethane 74-87-3
2-Chlorotoluene 95-49-8
4-Chlorotoluene 106-43-4
Dibromochloromethane 124-48-1
l,2-Oibromo-3-chloropropane 96-12-8
1,2-Oibromoethane 106-93-4
Dibrotnomethane 74-95-3
1,2-OiChlorobenzene 95-50-1
1,3-01Chlorobenzene 541-73-1
1,4-01Chlorobenzene 106-46-7
Dichlorodifluoromethane 75-71-8
1,1-Oichloroethane 75-34-3
1,2-OiChloroethane 107-06-2
1,1-Oichloroethene 75-35-4
cis-l,2-0ichloroethene 156-59-4
-71 r
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Chemical Abstract Services
Analyte Registry Number
trans-l,2-0ich1oroethene 156-60-5
1,2-Dichloropropane 78-87-5
1,3-Dichloropropane 142-28-9
2,2-Oichloropropane 590-20-7
1,1-Dichloropropene 563-58-6
Ethyl benzene 100-41-4
Hexachlorobutadiene 87-68-3
Isopropylbenzene 98-82-8
p-Isopropyltoluene* 99-87-6
Methylene chloride 75-09-2
Pentachloroethane 76-01-7
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
Toluene 108-88-3
1,2,3-Trichlorobenzene* 87-61-6
1,2,4-Tri ch1orobenzene* 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-Xylene 108-38-3
p-Xylene 106-42-3
*The measurement of this analyte can only be achieved using
chromatographic techniques that are less than optimum. The
preferred method of analysis is Method 503.1. See discussion in
Sect. 10.4.
1.2 Method detection limits (MDLs) (2) are compound dependent and vary
with purging efficiency and concentration. The MOLs for selected
analytes are presented in Table 1. The applicable concentration
range of this method is compound and instrument dependent but is
approximately 0.2 to 200 ug/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. Determination of
some geometrical isomers (i.e., xylenes) may be hampered by
coelution.
1.3 Based upon data obtained using Methods 502.1 or 503.1 or
on
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chemical similarity to other analytes, certain compounds were
included in the November 13, 1985 proposed monitoring regulation
without supporting accuracy and precision data using this method.
1.4 This method is recommended for use only by analysts experienced in
the measurement of purgeable organics at the low ug/L level or by
experienced technicians under the close supervision of a qualified
analyst.
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 the aqueous sample. Purged sample components are trapped
1n a tube containing suitable sorbent materials. When purging is
complete, the sorbent tube is heated and backflushed with helium to
desorb trapped sample components onto a gas chromatography (GO
column. The column is temperature programmed to separate the
method analytes which are then detected with a mass spectrometer
(MS) interfaced to the gas chromatograph.
2.2 Tentative identifications are confirmed by analyzing standards
under the same conditions used for samples and comparing resultant
mass spectra and GC retention times. Each identified component is
measured by relating the MS response for an appropriate selected
1on produced by that compound to the MS response for another 1on
produced by a compound that is used as an internal standard.
3. INTERFERENCES
3.1 Samples may be contaminated during shipment or storage by diffusion
of volatile organics through the sample bottle septum seal. Field
reagent blanks (Sect. 9.2.1) must be analyzed to determine if
contamination has occurred.
3.2 During analysis, major contaminant sources are volatile materials
1n the laboratory and impurities 1n 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
1n the trap during the purge operation. Analyses of field reagent
blanks (Sect. 9.2.1) and laboratory reagent blanks (Sect. 9.2.2)
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 (F1g. 1). Subtracting blank
values from sample results is not permitted.
3.3 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. For samples containing large
amounts of water soluble materials, suspended solids, high boiling
compounds or high levels of compounds being determined, it may be
necessary to wash out the purging device with a soap solution,
rinse it with reagent water, and then dry it in an oven at 105*C
between analyses.
3.4 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. SAFETY
4.1 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 (3-5) for the information of the analyst.
4.2 The following method analytes have been tentatively classified as
known or suspected human or mammalian carcinogens: benzene, carbon
tetrachloride, bis-2-chloroisopropyl ether, 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 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.
APPARATUS AND EQUIPMENT
5.1 SAMPLE CONTAINERS - 60-mL to 120-mL screw cap vials (Pierce #19832
or equivalent) each equipped with a PTFE-faced silicone septum
(Pierce #12718 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 in a 105*C
oven for one hour, then remove and allow to cool in an area known
to be free of organics.
-74-
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5.2 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.
5.2.1 The all glass purging device (Fig. 1) must be designed to
accept 25-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 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.
5.2.2 The trap (Fig. 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 analyze for
dichlorodifluoromethane, the charcoal can be eliminated and
the polymer increased to fill 2/3 of the 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 dail^ use, the trap should be
conditioned for 10 minutes 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.
5.2.3 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.
5.2.4 The^desorber must be capable of rapidly heating the trap to
180*C. 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 pounds per square inch across the trap during
purging or by poor bromoform sensitivities. The desorber
design illustrated in Fig. 2 meets these criteria.
5.2.5 Figures 3 and 4 show typical flow patterns for the
purge-sorb and desorb mode.
,75,
-------
5.3 GAS CHROMATOGRAPHY/MASS SPECTROMETER/DATA SYSTEM (GC/MS/DS)
5.3.1 The GC must be capable of temperature programming and should
be equipped with variable-constant differential flow
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 <30°C
(Sect. 10.3); therefore, a subambient oven controller may be
required. The GC usually is interfaced to the MS with an
all-glass enrichment device and an all-glass transfer line,
but any enrichment device or transfer line can be used if
the performance specifications described in Sect. 9.1 can be
achieved.
5.3.2 Gas Chromatographic Column - 1.5 to 2.5 m x 0.1 in ID
stainless steel or glass, packed with 1% SP-1000 on
Carbopack-8 (60/80 mesh) or equivalent. The flow rate of
the helium carrier gas is established at 40 mL/min. The
column temperature is programmed to hold at 45*C for three
min, increase to 220'C at 8°C/min, and hold at 220°C for 15
min or until all expected compounds have eluted. During
handling, packing, and programming, active sites can be
exposed on the Carbopack-B packing which can result in
tailing peak geometry and poor resolution of many
constituents. Pneumatic shocks and rough treatment of
packed columns will cause excessive fracturing of the
Carbopack. If pressure in excess of 60 psi is required to
obtain 40 mL/min carrier flow, the column should be
repacked. A sample chromatogram obtained with this column
is presented in Fig. 5.
5.3.3 Mass spectral data are obtained with electron-impact
iom'zation at a nominal electron energy of 70 eV. The mass
spectrometer must be capable of scanning from 35 to 450 amu
every 7s or less and must produce a mass spectrum that meets
all criteria in Table 1 when 50 ng or less of
4-bromofluorobenzene is introduced into the GC. To ensure
sufficient precision of mass spectral data, the desirable MS
scan rate allows acquisition of at least five spectra while
a sample component elutes from the GC.
5.3.4 An interfaced data system (DS) is required to acquire,
store, reduce and output mass spectral data. The computer
software must allow searching any GC/MS data file for ions
of a specific mass and plotting ion abundances versus time
or scan number. This type of plot is defined as an
extracted ion current profile (EICP). Software must also
allow integrating the abundance in any EICP between
specified time or scan number limits.
5.4 SYRINGE AND SYRINGE VALVES
-76-,
-------
5.4.1 Two 25-mL glass hypodermic syringes with Luer-Lok tip.
5.4.2 Three 2-way syringe valves with Luer ends.
5.4.3 One 25-uL micro syringe with a 2 in x 0.006 in ID, 22° bevel
needle (Hamilton #702N or equivalent).
5.4.4 Micro syringes - 10, 100 uL.
5.4.5 Syringes - 0.5, 1.0, and 5-mLs gas tight with shut-off valve.
5.5 MISCELLANEOUS
5.5.1 Standard solution storage containers - 15-mL bottles with
PTFE-lined screw caps.
6. REAGENTS AND CONSUMABLE MATERIALS
6.1 TRAP PACKING MATERIALS
6.1.1 2,6-Oiphenylene oxide polymer, 60/80 mesh, chromatographic
grade (Tenax GC or equivalent).
6.1.2 Methyl silicone packing (optional) - OV-1 (3%) on Chromo-
sorb W, 60/80 mesh, or equivalent.
6.1.3 Silica gel - 35/60 mesh, Davison, grade 15 or equivalent.
6.1.4 Coconut charcoal - Prepare from Barnebey Cheney, CA-580-26
lot #M-2649 by crushing through 26 mesh screen.
6.2 COLUMN PACKING MATERIALS
6.2.1 1% SP-1000 on 60/80 mesh Carbopack-8 or equivalent.
6.3 REAGENTS
6.3.1 Methanol - demonstrated to be free of analytes.
6.3.2 Reagent water - water meeting specifications in Sect.
9.2.2. 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.
6.3.3 Hydrochloric acid (1+1) - Carefully add measured volume of
cone. HC1 to equal volume of reagent water.
r77-
-------
6.3.4 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 are
available from several sources.
6.3.5 Reducing agent - Crystalline sodium thiosulfate, ACS Reagent
Grade or sodium sulfite, ACS Reagent Grade.
6.4 STANDARD STOCK SOLUTIONS - These solutions may be purchased as
certified solutions or prepared from pure standard materials using
the following procedures:
6.4.1 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 and weigh to the nearest 0.1 mg.
6.4.2 If the analyte is a liquid at room temperature, use a 100-uL
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 methano'l.
6.4.3 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.
6.4.4 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.
6.5 SECONDARY DILUTION STANDARDS - Use standard stock solutions to
prepare secondary dilution standard solutions that contain the
analytes in methanol. The secondary dilution standards should be
prepared at concentrations that can be easily diluted to prepare
aqueous calibration solutions (Sect. 8.1) that will bracket the
working concentration range. Store the secondary dilution standard
solutions with minimal headspace and check frequently for signs of
deterioration or evaporation, especially just before preparing
calibration solutions for them. Storage times described for stock
-78-
-------
standard solutions in Sect. 6.4.4 also apply to secondary dilution
standard solutions.
6.6 INTERNAL STANDARD SPIKING SOLUTION Prepare a spiking.solution
containing 1,4-dichlorobutane-dg, fluorobenzene, and
l,2-dichlorobenzene-d4 in methanol using the procedures described
in Sect. 6.4 and 6.5. It is recommended that the secondary
dilution standard be prepared at a concentration of 25 ug/mL of
each internal standard compound. The addition of 10 vl of such a
standard to 25.0 ml of sample or calibration standard would be
equivalent to 10 ug/L.
6.7 BFB STANDARD Prepare a 25-ug/mL solution of bromofluorobenzene
in methanol.
6.8 LABORATORY CONTROL STANDARD CONCENTRATE - Using standard stock
solutions, prepare a solution containing each analyte of interest
of a concentration of 10 ug/mL in methanol.
7. SAMPLE COLLECTION, PRESERVATION, AND STORAGE
7.1 SAMPLE COLLECTION
7.1.1 Replicate field reagent blanks 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 empty sample bottles. Wherever a set of
samples is shipped and stored, it must be accompanied by
field reagent blanks.
7.1.2 For samples collected to determine compliance with
trihalomethane regulations (40CFR, Part 141.30), add 2.5 to
3.0 mg reducing agent (Sect. 6.3.5) per 40 mL to the empty
sample bottles and blanks just prior to shipping to the
sampling site.
7.1.3 Collect all samples in duplicate. Fill sample bottles to
overflowing. No air bubbles should pass through the sample
as the bottle is filled, or be trapped in the sample when
the bottle is sealed.
7.1.4 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 from the flowing stream.
7.1.5 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 duplicate sample
bottles from the 1-quart container.
-------
7.2 SAMPLE PRESERVATION
7.2.1 Adjust the pH of the duplicate samples and the field reagent
blanks to <2 by carefully adding one drop of 1:1 HC1 for
each 20 ml of sample volume.(6) Seal the sample bottles,
PFTE-face down, and shake vigorously for one minute.
7.2.2 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 that they will be at 4*C on arrival
at the laboratory.
7.3 SAMPLE STORAGE
7.3.1 Store samples and field reagent blanks together at 4*C until
analysis. The sample storage area must be free of organic
solvent vapors.
7.3.2 Analyze all samples within 14 days of collection. Samples
not analyzed within this period must be discarded and
replaced.
8. CALIBRATION AND STANDARDIZATION
8.1 PREPARATION OF CALIBRATION STANDARDS
8.1.1 A set of at least five calibration standards containing the
method analytes is needed. One calibration standard should
contain each analyte at a concentration approaching but
greater than the method detection limit (Table 1) for that
compound; the other calibration standards should contain
analytes at concentrations that define the range of the
method.
8.1.2 To prepare a calibration standard, add an appropriate volume
of a secondary dilution standard solution to an aliquot of
reagent water in a volumetric flask. Do not add less than
20 uL of an alcoholic standard to the reagent water or poor
precision will result. Use a 25-uL microsyringe 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 three
times only. Discard the contents contained in the neck of
the flask. Aqueous standards are not stable and should be
discarded after one hour unless sealed and stored as
described in Sect. 7.2.2.
8.2 CALIBRATION
8.2.1 After meeting the BF8 criteria in Sect. 9.5, analyze each
-80-
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calibration standard according to Sect. 10, adding 10 uL of
internal standard spiking solution directly to the syringe.
Tabulate area response of the characteristic m/z versus the
concentration for each analyte and internal standard.
Calculate response factor's (RF) for each analyte using
Equation 1:
RF a (As)(Cis) Equation 1
I" & A / (** )
» 4 £ I \ f I
where:
As a Area of the characteristic m/z for the analyte to be
measured.
AiS - Area of the characteristic m/z for the internal
standard.
CTS a Concentration of the internal standard, in ug/L.
Cs a Concentration of the analyte to be measured, in ug/L.
The choice of which internal standard is used for an analyte
is left to the analyst. Normally all aromatics are compared
to l,2-dichlorobenzene-d4 and all other analytes are
compared to the internal standard having the closest
relative retention time.
8.2.2 The results are used to prepare a calibration curve for each
analyte. Alternatively, if the RF for an analyte is
constant (less than 10% RSD) over the working range, the
average RF can be used for that analyte.
8.2.3 The working calibration curve or average response factor
must be verified on each working day by the measurement of
one or more calibration standards. If the quantisation ion
area for any analyte varies from the response determined for
that standard concentration from the calibration curve or
average RF established in Sect. 8.2.2 by more than ±20%,
repeat steps 8.2.1 and 8.2.2.
8.2.4 Calibration for vinyl chloride using a certified gaseous
mixture of vinyl chloride in nitrogen can be accomplished by
the following steps.
8.2.4.1 Fill the purging device with 25.0 mL of reagent
water or aqueous calibration standard.
8.2.4.2 Start to purge the aqueous mixture. Inject a known
volume (between 100 and 2000 UL) 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
-81-
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the purging device at 2000 ul_/min. Do not inject
the standard through the aqueous sample inlet
needle. Inject the gaseous standard before five nin
of the li-nin purge time have elapsed.
8.2.4.3 Determine the aqueous equivalent concentration of
vinyl chloride standard, in ug/L, injected with the
equation:
S = 0.102 (C)(V)
where S =» Aqueous equivalent concentration
of vinyl chloride standard in ug/L;
C 3 Concentration of gaseous standard in ppm;
V » Volume of standard injected in mini-
liters.
9. QUALITY CONTROL
9.1 PRECISION TEST
9.1.1 The analyst must make an initial one-time, demonstration of
the ability to generate acceptable precision with this
method. The purpose of this test is to demonstrate that the
equipment configuration and the technique of the analyst are
adequate to produce data of acceptable quality.
9.1.2 Prepare a laboratory control standard to contain 20 ug/L of
each .analyte by adding 200 uL of laboratory control standard
concentrate (Sect. 6.8) to 100 ml of. reagent water.
9.1.3 Analyze four 25-mL aliquots of the well-mixed laboratory
control standard according to the procedure in Sect. 10.
9.1.4 For each analyte, calculate the standard deviation in ug/L,
of the measured concentration. For each analyte, the
standard deviation must be less than 4.0 ug/L.
9.1.5 If the standard deviation for any analyte exceeds the listed
criterion in Sect. 9.1.4, locate and correct the source of
the problem and repeat the test for all analytes.
9.2 MONITORING FOR INTERFERENCES
9.2.1 Field Reagent Blanks - A field reagent blank (Sect. 7.1.1)
is a sealed bottle of reagent water that accompanies a set
of sample bottles from the laboratory to a sampling site and
back. Analyze a field reagent blank along with each sample
set. If the field reagent blank contains a reportable level
of any analyte, analyze a laboratory reagent blank as
described in Sect. 9.1.2. If the contamination is not
detected in the laboratory reagent blank, the sampling or
-------
transportation practices have caused the contamination. In
this case, discard all samples in the set and resample the
site.
9.2.2 Laboratory Reagent Blanks - A laboratory reagent blank is a
25-mL aliquot of reagent water analyzed as if it were a
sample. Analyze a laboratory reagent blank each time fresh
reagent water is prepared and as necessary to identify
sources of contamination. The laboratory reagent blank
should represent less than 0.1 wg/L response (see Sect. 3).
9.3 ASSESSING ACCURACY
9.3.1 At least quarterly, analyze a quality control check sample
obtained from the U.S. Environmental Protection Agency,
Environmental Monitoring and Support Laboratory (EMSL),
Quality Assurance Branch, Cincinnati. If measured analyte
concentrations are not within acceptance limits provided
with the sample, check the entire analytical procedure to
locate and correct the problem source.
9.3.2 After every 10 samples, and preferably in the middle of each
day, analyze a laboratory control standard. Calibration
standards may not be used for accuracy assessments and the
laboratory control standard may not be used for calibration
of the analytical system.
9.3.2.1 Analyze a 25-mL aliquot of a laboratory control
standard (Sect. 9.1.2) as described in Sect. 10.
For each analyte in the laboratory control standard,
calculate the percent recovery (P^) with the
equation:
P. - . wo si
~
where S-j - the analytical result from the
laboratory control standard, in ug/L; and
T-j « the known concentration of the spike,
in ug/L.
9.3.2.2 Recovery data can be pooled to develop an expression
of method accuracy for each analyte. These accuracy
statements should be updated regularly for on-going
quality assurance.
9.3.3 At least annually, the laboratory should participate in
formal performance evaluation studies, where solutions of
unknown concentrations are analyzed and the performance of
all participants is compared.
-------
9.4 ASSESSING PRECISION
9.4.1 Precision assessments for this method are based upon the
analysis of field duplicates (Sect. 7.1). Analyze both
sample bottles for at least 10% of all samples. To the
extent practical, the samples selected for duplication
should contain reportable levels of many analytes.
9,4.2 For each analyte in each duplicate pair, calculate the
relative range (RR-j) with the equation:
RR. = Ri
Xi
where Rj = the absolute difference between the
duplicate measurements X]_ and Xj, in
wg/L
Xj = the average concentration found
(C*l * X2]/2), in ug/L.
9.4.3 Individual relative range measurements can be pooled to
determine average relative range or to develop an expression
of relative range as a function of concentration.
9.5 DAILY GC/MS 'PERFORMANCE TESTS
9.5.1 At the beginning of each day that analyses are to be
performed, the GC/MS system must be checked to see if
acceptable performance criteria are achieved for BFB (7).
The performance test must be passed before any samples,
blanks, or standards are analyzed.
9.5.2 At the beginning of each day, inject 2 uL (50 ng) of BFB
solution directly on the column. Alternatively, add 2 uL of
BFB solution to 25.0 mL of reagent water or calibration
standard and analyze the solution according to Sect. 10.
Obtain a background-corrected mass spectrum of BFB and
confirm that all the key m/z criteria in Table 2 are
achieved. If all the criteria are not achieved, the analyst
must retune the mass spectrometer and repeat the test until
all criteria are achieved.
10. PROCEDURE
10.1 INITIAL CONDITIONS
10.1.1 Acquire GC/MS data for performance tests, standards and
samples using the following instrumental parameters:
Electron Energy: 70 V (nominal)
Mass Range: 20 to 270 amu
Scan Time: To give at least 5 scans per peak but
not to exceed 7 s per scan.
-84-
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10.1.2 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.
10.2 SAMPLE INTRODUCTION AND PURGING
10.2.1 Remove the plungers from two 25-ml syringes and attach a
closed syringe valve to each. Warm the sample 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 syringe, and compress the sample. Open the
syringe valve and vent any residual air while adjusting the
sample volume to 25.0 mL. Add 10 uL 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.
10.2.2 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 (Fig. 3).
10.3 SAMPLE DESORPTION - After the 11-min purge, attach the trap to the
chromatograph, adjust the purge and trap system to the desorb mode
(Fig. 4) and initiate the temperature program sequence of the gas
chromatograph. Introduce the trapped materials to the GC column by
rapidly heating the trap to 180*C while backflushing the trap with
an inert gas between 20 and 60 mL/min for 4.0 ± 0.1 min. If rapid
heating cannot be achieved, the GC^column must be used as a
secondary trap by cooling it to 30*C (subambient temperature if
poor peak geometry and random retention problems persist) instead
of the initial operating temperature for analysis. While the
extracted sample is being introduced into the gas chromatograph,
empty the purging device using the sample syringe and wash the
chamber with two 25-mL flushes of reagent water. After the purging
device has been emptied, leave the syringe valve open to allow the
purge gas to vent through the sample introduction needle.
10.4 GAS CHROMATOGRAPHY - The column described in this method is less
than optimum for the analytes footnoted in Sect. 1.1. Method 503.1
is the method of choice for these analytes. However, in an effort
to offer the maximum number of analytical options to the regulated
community, this method permits two options for gas chromatography
to meet the proposed monitoring requirements through a single
analysis. These options are described below.
10.4.1 Hold^the column temperature at 40*C for 3 min, then program
at 8*C/min to 220*C and hold until all analytes elute. This
-85-.
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procedure results in excessively long (704- minutes)
determinations, broad peaks for a numoer of late eluting
analytes and a relatively poor detection limit for tnese
compounds.
10.4.2 Hold^the column temperature at 40"C for 3 min, then program
at 8"C/min to 245*C and hold until all analytes elute. This
procedure exceeds the recommended maximum temperature for
the column and may reduce the column life and affect
separations. The trichlorobenzenes will have broad peaks
and poor detection limits.
10.4.3 Chromatograph the analytes footnoted in Sect. 1.1 by
substituting the SP-1200/Bentone 34 column from Method 503.1
and selecting one of the temperature programs described in
that method for incorporation into this method.
10.5 TRAP RECONDITIONING - After desorbing the sample for 4 min,
recondition the trap by returning the purge and trap system to the
purge mode. Wait 15 s, then close the syringe valve on the purging
device to begin gas flow through the trap. Maintain the trap
temperature at 180*C. 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.
10.6 TERMINATION OF DATA ACQUISITION - When sample components have
eluted from the GC, terminate MS data acquisition and store-data
files on the data system storage device. Use appropriate data
output software to display full range mass spectra and appropriate
EICPs. If any ion abundance exceeds the system working range,
dilute the sample aliquot in the second syringe with reagent water
and analyze the diluted aliquot.
11. QUALITATIVE IDENTIFICATION
11.1 Obtain EICPs for the primary m/z (Table 4) and the secondary masses
listed for each analyte. The following criteria must be met to
make a qualitative identification:
11.1.1 The characteristic masses of each analyte of interest must
maximize in the same or within one scan of each other.
11.1.2 The retention time must fall within * 30 s of the retention
time of the authentic compound.
11.1.3 The relative peak heights of the three characteristic masses
in the EICPs must fall within * 20% of the relative
intensities of these masses in a reference mass spectrum.
The reference mass spectrum can be obtained from a standard
analyzed in the GC/MS system or from a reference library.
11.2 Structural isomers that have very similar mass spectra (e.g.
dichlorobenzenes and xylenes) and less than 30 s difference in
-86-
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retention time, can be explicitly identified only if the resolution
between authentic isomers in a standard mix is acceptable.
Acceptable resolution is achieved if the baseline to valley height
between the isomers is less than 25% of the sum of the two peak
heights. Otherwise, structural isomers are identified as isomeric
pairs.
12. CALCULATIONS
12.1 When an analyte has been identified, the quantisation of that
analyte should be based on the integrated abundance from the EICP
of the primary characteristic m/z given in Table 4. If the sample
produces an interference for the primary m/z, use a secondary
characteristic m/z to quantitate. Instrument calibration for
secondary ions is performed, as necessary, using the data and
procedures described in Sect. 8.2.
12.2 Calculate the concentration in the sample using the calibration
curve or average response factor (RF) determined in Sect. 8.2.2 and
Equation 2:
Concentration (ug/L) (AsHCiS) Equation 2.
(Ais)(RF)
where:
As » Area of the characteristic m/z for the analyte
to be measured.
Area of the characteristic m/z for the internal
standard.
C-jS» Concentration of the internal standard, in ug/L.
12.3 Report results in ug/L. All QC data obtained should be reported
with the sample results.
13. ACCURACY AND PRECISION
13.1 This method was tested in a single laboratory using reagent water
spiked at concentrations between 1 and 5 ug/L. (8) Single operator
precision and accuracy data are presented for some selected
analytes in Table 3.
13.2 Method detection limits have been calculated for some analytes from
data collected in three laboratories. (1,8,9) These data are
summarized in Table 1.
14. REFERENCES
1. A. Alford-Stevens, J.W. Eichelberger, W.L. Sudde, "Purgeable Organic
Compounds in Water by Gas Chromatography/ Mass Spectrometry, Method
524." Environmental Monitoring and Support Laboratory, U.S.
Environmental Protection Agency, Cincinnati, Ohio, February 1983.
-87-
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2. Glaser, J.A., O.L. Foerst, G.D. McKee, S.A. Quave, and W.L. Budde,
"Trace Analyses for Wastewaters," Environ. Sci. Techno!., 15, 1426, 1981.
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. Bellar, T.A. and J.J. Lichtenberg, "The Determination of Synthetic
Organic Compounds in Water by Purge and Sequential Trapping Capillary
Column Gas Chromatography," U.S. Environmental Protection Agency,
Environmental Monitoring and Support Laboratory, Cincinnati, Ohio,
January 1985.
7. Budde, W.L. and Eichelberger, J.W., "Performance Tests for the
Evaluation of Computerized Gas Chromatography/Mass Spectrometry
Equipment and Laboratories," EPA-600/4-80-025, U. S. Environmental
Protection Agency, Environmental Monitoring and Support Laboratory,.
Cincinnati, OH 45258.
8. Slater, R.W., "Method Detection Limits for Drinking Water Volatiles,"
Unpublished report, March 1985.
9. Sorrel 1, R.K., Private Communication, May 1985.
-88-
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Table 1. CHROMATOGRAPHIC CONDITIONS AND METHOD DETECTION LIMITS (MDL)
FOR VOLATILE ORGANIC COMPOUNDS
Retention Time^ Method Detection Limits (ug/L)
Analyte (m1n) Ref. 1 Ref. 8 Ref. 9
Vinyl chloride
Dichlorodifluoromethane
Methyl ene chloride
Trichlorofluoromethane
1 , 1-Oi chl oroethene
Bromochloromethane
1,1-Oichloroethane
trans-1 , 2-Di ch 1 oroethene
Chloroform
Dibromomethane
1,2-Dichloroethane
2,2-Oichloropropane
1,1,1-Trichloroethane
Carbon tetrachloride
Bromodi ch 1 oromethane
1,2-Oichloropropane
1,1-Dichloropropene
Tri chl oroethene
Benzene
Di bromoch 1 oromethane
1,2-Oibromoethane
1,3-Oichloropropane
Bromoform
1,1,2,2-Tetrachloroethane
Tetrach 1 oroethene
Toluene
Pentachloroethane
Chlorobenzene
l,2-Oibromo-3-ch1oropropane
Bromobenzene
I sopropyl benzene
m-Xylene
Styrene
n-Propyl benzene
o-Xylene
.p-Xylene
bis-(2-Chloroi sopropyl ) ether
t-Butyl benzene
3.8
3.8
6.4
8.3
9.0
9.3
10.1
10.8
11.4
12.1
12.1
12.7
13.4
13.7
14.3
15.7
16.0
16.5
17.0
17.1
17.9
18.4
19.8
22.1
22.2
23.5
24.6
24.6
25.8
26.7
28.5 (28.2)3
29-. 5 (29.0)
29.7 (29.2)
30.7 (30.4)
30.9 (30.4)
30.9 (30.4)
31.1 (30.8
31.5 (30.5)
2
_
0.25
__
0.27
>
1.7
0.20
0.35
0.13
0.13
0.29
0.18
0.21
0.34
.
0.34
0.28
0.07
0.08
0.09
__
1.3
__
0.18
0.31
0.33
0.13
0.21
0.19
__
0.17
0.19
0.24
0.30
0.22
__
0.26
0.28
0.28
0.17 '
0.36
0.10
0.30
0.36
0.10
0.66
0.41
0.29
0.12
0.14
1.8
0.12
0.20
0.20
0.13
_
_
_
0.2
0.1
_
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.5
0.2
0.2
,
0.2
_
-------
Analyte
Table 1. (Continued)
Retention Time^ Method Detection Limits (wg/L)
(min) Ref. 1 Ref. 8 Ref. 9
2-Chlorotoluene
Hexachlorobutadiene
4-Chlorotoluene
sec-Butyl benzene
1,2-Oichlorobenzene
1 , 4-Qi ch 1 orobenzene
p-Isopropyltoluene
n-Butyl benzene
1,3, 5-Tri methyl benzene
1, 2, 4-Trimethyl benzene
1, 2, 4-Trichl orobenzene
1, 2, 3-Trichl orobenzene
31.5 (30.5)
32.0 (30.9)
32.5 (31.6)
32.5 (31.5)
35.0 (33.8)
35.3 (34.0) 0.3
40.9 (35.7)
45.5 (38.0)
46.5 (38.6)
51.0 (40.5)
71.0 (51.5)
77.5 (53.9)
1.0
2.0
.
,
_
0.1
__
.
«_
1 Column Conditions: 2 m x 2 mm ID glass column packed with Carbopack B
(60-80 mesh) coated with 1% SP-1000. Carrier gas - Helium at flow of
. 30 mL/min. Column temperature held at 45*C for 3 min, then programmed at
3*C/min to 220*C and held until all analytes elute.
2 Not Determined
3 Values in parentheses refer to retention times when the final hold
temperature is raised to 245*C. See Sect. 10.4 for discussion.
-90-
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Table 2. BFB KEY m/z ABUNDANCE CRITERIA
Mass m/z Abundance Criteria
50 15 to 40% of mass 95
75 30 to 60% of mass 95
95 Base Peak, 100% Relative Abundance
96 5 to 9% of mass 95
173 < 1% of mass 95
174 > 50% of mass 95
175 5 to 9% of mass 174
176 > 95% but < 101% of mass 174
177 5 to 9% of mass 176
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Table 3. SINGLE LABORATORY ACCURACY AND PRECISION DATA FOR
VOLATILE ORGANIC COMPOUNDS IN REAGENT WATER
Analyte
Benzene
Bromobenzene
Bromodichloromethane
Bromoform
Carbon tetrachloride
Chlorobenzene
Chloroform
Oibromochloromethane
1 , 2-Oi bromo-3-ch 1 oropropane
1,2-Oibromoethane
Oibromome thane
1,2-Oi chlorobenzene
1 , 4-Oi chl orobenzene
Di chl orodi f 1 uoromethane
1,1-Qichloroethane
1,2-Qichloroethane
lsl-0ichloroethene
trans-1 , 2-Oi ch 1 oroethene
1 , 2-Oi ch 1 oropropane
1 , 3-0 i ch 1 oropropane
Methyl ene chloride
Styrene
1,1,2,2-Tetrachloroethane
Tetr ach 1 oroethene
Toluene
1,1,1-Trichloroethane
Tri chl oroethene
Tr i ch 1 orof 1 uoromethane
Vinyl chloride
o-Xylene
p-Xylene
Cone.
Tested
ug/L
1.0
1.0
1.5
2.5
1.0
1.0
1.0
1.5
3.0
1.0
1.0
5.0
5.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0 '
1.0
1.0
1.0
Number
of
Samples
8
8
8
8
8
8
8
8
8
8
8
8
3
8
8
8
8
8
8
8
7
8
8
8
8
a
a
7
8
a
8
Average
Cone.
Measured
ug/L
0.97
0.92
1.43
2.36
0.88
1.02
1.03
1.49
3.4
0.93
0.94
4.95
5.27
0.96
1.05
0.97
1.09
0.98
1.01
1.00
0.99
1.06
1.11
0.93
1.05
1.05
0.90
1.09
0.98
1.02
1.11
Standard
Deviation
ug/L
0.036
0.042
0.096
0.23
0.098
0.047
0.086
0.10
0.63
a. 13
0.11
0.35
0.72
0.11
0.060
0.077
0.066
0.066
0.060
0.033
0.045
0.066
0.14
0.10
0.043
0.093
0.12
0.072
0.11
0.068
0.047
Percent
Rel. Std.
Dev.
3.6
4.6
6.7
9.7
11.1
4.6
8.4
7.0
18.2
13.6
11.4
7.1
13.6
11.9
5.9
7.9
6.1
6.8
5.9
3.4
4.5
6.2
12.8
10.9
4.1
8.8
13.6
6.6
10.8
6.7
4.2
.92-
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Table 4. CHARACTERISTIC MASSES (m/z) FOR PURGEABLE ORGANICS
Analyte
Benzene
Bromobenzene
Bromoch 1 oromethane
Bromod 1 ch 1 oromethane
Bromoform
Bromomethane
n-Butyl benzene
sec-Butyl benzene
tert-Butyl benzene
bis-2-Chloroisopropyl ether
Carbon tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chi oromethane
2-Chlorotoluene
4-Chlorotoluene
Dibromochl oromethane
1 ,2-Di bromo-3-ch 1 oropropane
1 , 2-01 bromoethane
Qibromomethane
1,2-Dichlorobenzene
1,3-Di Chlorobenzene
1 , 4-Oi ch 1 orobenzene
Dichlorodifluoromethane
1,1-Di Chloroethane
1,2-Oichloroethane
1,1-Di chloroethene
cis-l,2-0ichloroethene
trans-1 , 2-Oi ch 1 oroethene
1,1-Oichloropropane
1,2-Dichloropropane
1,3-Oichloropropane
2,2-Oichloropropane
1,1-Oichloropropene
Ethyl benzene
Hexachlorobutadiene
Isopropyl benzene
p-I sopropy 1 to 1 uene
Methyl ene chloride
-Pent ach 1 oroethane
n-P ropy! benzene
Styrene
1,1,1, 2-Tetr ach 1 oroethane
Primary
Ion
78
77
128
127
173
94
91
105
119
45
117
112
64
83
50
91
91
127
75
107
93
146
146
146
85
63
98
96
96
96
63
112
76
77
110
106
225
91
119
84
117
91
104
131
Secondary
Ions
156, 158
49, 130
83, 85, 129
171, 175, 250
96
92, 134
134
91, 134
77, 79
119, 121
114
66
85
52
126
126
129, 208
155, 157
109, 188
95, 174, 176
148, 113
148, 111
148, 113
87, 111
65, 83, 85
62, 64, 100
61, 98
61, 98
61, 98
41, 77
63, 114
78
97, 41, 99
112, 77
91
223, 227
120
134, 91
49, 51, 86
119, 95, 167
120
78
133, 117, 119
-93-
-------
Table 4.
[Continued]
Analyte
1,1,2,2-Tetrachloroethane
Tetrach 1 oroethene
1,2, 3-Tri ch 1 orobenzene
1,2,4-Trichlorobenzene
1,1,2-Trichloroethane
1,2,3-Trichloropropane
1,2, 4-Trimethyl benzene
1 , 3, 5-Trimethyl benzene
Toluene
1,1, 1-Tri ch 1 oroethane
Trichloroethene
Tri ch 1 orof 1 uoromethane
Vinyl chloride
m-Xylene
o-Xylene
p-Xylene
Primary
Ion
168
164
180
180
97
75
105
105
92
97
130
101
62
91
91
91
Secondary
Ions
83, 85
129, 131
182, 145
182, 145
83, 99
77, 110, 112
120
120
91
99, 117
95, 97
103
64
106
106
106
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DUF
COLUMN: 1% SP-10CO ON CARSOPACX-a
PROGRAM: 45 °C FOR 3 MIN, 3*C/M1N TO
DETECTOR: MASS SPECTROMETER
10 12 1* 14 19- 20
RETENTION TIMS. MIN.
25
Figure 5. Gas chromatogram of volatile organics.
r99-
U.S. Environmental Protection Agency
Region V, Library
230 South Dearborn Street
Chic*qo, Illinois 60604
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