ASTM D5790-95
(Test Method)Standard Test Method for Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry
Standard Test Method for Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry
SCOPE
1.1 This test method covers the identification and simultaneous measurement of purgeable volatile organic compounds. It has been validated for treated drinking water, wastewater, and ground water. This test method is not limited to these particular aqueous matrices; however, the applicability of this test method to other aqueous matrices must be demonstrated.
1.2 This test method is applicable to a wide range of organic compounds that have sufficiently high volatility and low water solubility to be efficiently removed from water samples using purge and trap procedures. Table 1 lists the compounds that have been validated for this test method. This test method is not limited to the compounds listed in Table 1; however, the applicability of the test method to other compounds must be demonstrated.
1.3 Analyte concentrations up to approximately 200 μg/L may be determined without dilution of the sample. Analytes that are inefficiently purged from water will not be detected when present at low concentrations, but they can be measured with acceptable accuracy and precision when present in sufficient amounts.
1.4 Analytes that are not separated chromatographically, but that have different mass spectra and noninterfering quantitation ions, can be identified and measured in the same calibration mixture or water sample. Analytes that have very similar mass spectra cannot be individually identified and measured in the same calibration mixture or water sample unless they have different retention times. Coeluting compounds with very similar mass spectra, such as structural isomers, must be reported as an isomeric group or pair. Two of the three isomeric xylenes are examples of structural isomers that may not be resolved on the capillary column, and if not, must be reported as an isomeric pair.
1.5 It is the responsibility of the user to ensure the validity of this test method for untested matrices.
1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 5790 – 95
Standard Test Method for
Measurement of Purgeable Organic Compounds in Water by
Capillary Column Gas Chromatography/Mass Spectrometry
This standard is issued under the fixed designation D 5790; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
1.1 This test method covers the identification and simulta-
priate safety and health practices and determine the applica-
neous measurement of purgeable volatile organic compounds.
bility of regulatory limitations prior to use.
It has been validated for treated drinking water, wastewater,
and ground water. This test method is not limited to these
2. Referenced Documents
particular aqueous matrices; however, the applicability of this
2.1 ASTM Standards:
test method to other aqueous matrices must be demonstrated.
D 1129 Terminology Relating to Water
1.2 This test method is applicable to a wide range of organic
D 2777 Practice for Determination of Precision and Bias of
compounds that have sufficiently high volatility and low water
Applicable Methods of Committee D-19 on Water
solubility to be efficiently removed from water samples using
D 3871 Test Method for Purgeable Organic Compounds in
purge and trap procedures. Table 1 lists the compounds that
Water Using Headspace Sampling
have been validated for this test method. This test method is not
D 3973 Test Method for Low-Molecular Weight Haloge-
limited to the compounds listed in Table 1; however, the
nated Hydrocarbons in Water
applicability of the test method to other compounds must be
D 4210 Practice for Intralaboratory Quality Control Proce-
demonstrated.
dures and a Discussion on Reporting Low-Level Data
1.3 Analyte concentrations up to approximately 200 μg/L
E 355 Practice for Gas Chromatography Terms and Rela-
may be determined without dilution of the sample. Analytes
tionships
that are inefficiently purged from water will not be detected
2.2 Other Document:
when present at low concentrations, but they can be measured
Code of Federal Regulations, 40 CFR Part 261
with acceptable accuracy and precision when present in suffi-
cient amounts.
3. Terminology
1.4 Analytes that are not separated chromatographically, but
3.1 Definitions:
that have different mass spectra and noninterfering quantitation
3.1.1 For definitions of terms used in this test method, refer
ions, can be identified and measured in the same calibration
to Definitions D 1129 and Practice E 355.
mixture or water sample. Analytes that have very similar mass
3.2 Definitions of Terms Specific to This Standard:
spectra cannot be individually identified and measured in the
3.2.1 calibration standard—a solution prepared from the
same calibration mixture or water sample unless they have
primary dilution standard solution and stock standard solutions
different retention times. Coeluting compounds with very
of the internal standards and surrogate analytes. The calibration
similar mass spectra, such as structural isomers, must be
standards are used to calibrate the instrument response with
reported as an isomeric group or pair. Two of the three isomeric
respect to analyte concentration.
xylenes are examples of structural isomers that may not be
3.2.2 field duplicates —two separate samples collected at
resolved on the capillary column, and if not, must be reported
the same time and place under identical circumstances and
as an isomeric pair.
treated exactly the same throughout field and laboratory
1.5 It is the responsibility of the user to ensure the validity
procedures. Analysis of field duplicates gives an indication of
of this test method for untested matrices.
the precision associated with sample collection, preservation,
1.6 The values stated in SI units are to be regarded as the
and storage, as well as with laboratory procedures.
standard. The values given in parentheses are for information
3.2.3 field reagent blank—reagent water placed in a sample
only.
container, taken to the field along with the samples, and treated
1.7 This standard does not purport to address all of the
Annual Book of ASTM Standards, Vol 11.01.
1 3
This test method is under the jurisdiction of ASTM Committee D-19 on Water Annual Book of ASTM Standards, Vol 11.02.
and is the direct responsibility of Subcommittee D19.06 on Methods for Analysis for Annual Book of ASTM Standards, Vol 14.01.
Organic Substances in Water. Available from the Superintendent of Documents, U.S. Government Printing
Current edition approved Sept. 10, 1995. Published November 1995. Office, Washington, DC 20402.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 5790
as a sample in all respects, including exposure to sampling site 3.2.13 stock standard solution—a concentrated solution
conditions, storage, preservation, and all analytical procedures. containing a single certified standard that is a test method
The purpose of the field reagent blank is to determine if test analyte prepared in the laboratory with an assayed reference
method analytes or other interferences are present in the field compound. Stock standard solutions are used to prepare
environment. primary dilution standards. Commercially available stock stan-
dard solutions may be used.
3.2.4 internal standard—a pure analyte added to a solution
3.2.14 surrogate analyte—a pure analyte that is extremely
in a known amount, that is used to measure the relative
unlikely to be found in any sample, that is added to a sample
responses of other test method analytes and surrogates that are
aliquot in a known amount, and is measured with the same
components of the same solution. The internal standard must
procedures used to measure other components. The purpose of
be an analyte that is not a sample component.
a surrogate analyte is to monitor test method performance with
3.2.5 laboratory duplicates—two sample aliquots taken in
each sample.
the analytical laboratory and analyzed separately with identical
procedures. Analysis of laboratory duplicates gives an indica-
4. Summary of Test Method
tion of the precision associated with laboratory procedures, but
4.1 Volatile organic compounds with low water-solubility
not with sample collection, preservation, or storage procedures.
are purged from the sample matrix by bubbling an inert gas
3.2.6 laboratory-fortified blank—an aliquot of reagent
through the aqueous sample. Purged sample components are
water to which known quantities of the test method analytes are
trapped in a tube containing suitable sorbent materials. When
added in the laboratory. The laboratory-fortified blank is
purging is complete, the sorbent tube is heated and backflushed
analyzed exactly like a sample, and its purpose is to determine
with inert gas to desorb the trapped sample components into a
whether the methodology is in control and whether the
capillary gas chromatography (GC) column interfaced to a
laboratory is capable of making accurate and precise measure-
mass spectrometer (MS). The GC column is temperature
ments at the required detection limit.
programmed to separate the test method analytes which are
3.2.7 laboratory-fortified sample matrix—an aliquot of an
then detected with the MS. Compounds eluting from the GC
environmental sample to which known quantities of the test
column are identified by comparing their measured mass
method analytes are added in the laboratory. The laboratory-
spectra and retention times to reference spectra and retention
fortified sample matrix is analyzed exactly like a sample, and
times in a database. Reference spectra and retention times for
its purpose is to determine whether or not the sample matrix or
analytes are obtained by the measurement of calibration
the addition of preservatives or dechlorinating agents to the
standards under the same conditions used for the samples. The
sample contributes bias to the analytical results. The back-
concentration of each identified component is measured by
ground concentrations of the analytes in the sample matrix
relating the MS response of the quantitation ion produced by
must be determined in a separate aliquot, and the measured
that compound to the MS response of the quantitation ion
values in the laboratory-fortified sample matrix must be
produced by a compound that is used as an internal standard.
corrected for background concentrations.
Surrogate analytes, whose concentrations are known in every
3.2.8 laboratory performance check solution—a solution of
sample, are measured with the same internal standard calibra-
one or more compounds (analytes, surrogates, internal stan-
tion procedure.
dard, or other test compounds) used to evaluate the perfor-
mance of the instrument system with respect to a defined set of
5. Significance and Use
test method criteria.
5.1 Purgeable organic compounds have been identified as
3.2.9 laboratory reagent blank —an aliquot of reagent
contaminants in treated drinking water, wastewater, ground
water that is treated exactly as a sample including exposure to
water, and Toxicity Characteristic Leaching Procedure (TCLP)
all glassware, equipment, solvents, reagents, internal standards,
leachate. These contaminants may be harmful to the environ-
and surrogates that are used with other samples. The laboratory
ment and to people. Purge and trap sampling is a generally
reagent blank is used to determine if test method analytes or
applicable procedure for concentrating these components prior
other interferences are present in the laboratory environment,
to gas chromatographic analysis.
the reagents, or the apparatus.
3.2.10 primary dilution standard solution—a solution of 6. Interferences
several analytes prepared in the laboratory from stock standard
6.1 During analysis, major contaminant sources are volatile
solutions and diluted as needed to prepare calibration solutions
materials in the laboratory and impurities in the inert purging
and other needed analyte solutions.
gas and in the sorbent trap. Avoid the use of plastic tubing or
3.2.11 purgeable organic—any organic material that is
thread sealants other than PTFE, and avoid the use of flow
removed from aqueous solution under the purging conditions
controllers with rubber components in the purging device.
described in this test method.
These materials out-gas organic compounds that will be
3.2.12 quality control sample—a sample matrix containing concentrated in the trap during the purge operation. Analyses
test method analytes or a solution of method analytes in a of laboratory reagent blanks provide information about the
water-miscible solvent that is used to fortify reagent water or presence of contaminants. When potential interfering peaks are
environmental samples. The quality control sample is obtained noted in laboratory reagent blanks, the analyst should change
from a source external to the laboratory and is used to check the purge gas source and regenerate the molecular sieve purge
laboratory performance with externally prepared test materials. gas filter. Reagents should also be checked for the presence of
D 5790
contaminants. Subtracting blank values from sample results is 7.2.2 Trap:
not permitted. 7.2.2.1 The trap shall be at least 25 cm long and have an
6.2 Interfering contamination may occur when a sample inside diameter of at least 0.267 cm. Starting from the inlet, the
containing low concentrations of volatile organic compounds is trap should contain 1.0 cm of methyl silicone coated packing
analyzed immediately after a sample containing higher con- and the following amounts of adsorbents: ⁄3 of 2,6-
1 1
centrations of volatile organic compounds. Experience gained diphenylene oxide polymer (Tenax ), ⁄3 of silica gel, and ⁄3 of
from the test method validation has shown that there is a coconut charcoal. If it is not necessary to determine dichlo-
carryover of approximately 2 % of the concentration of each rodifluoromethane, the charcoal can be eliminated and the
analyte from one sample to the next. The effect was observed polymer increased to fill two thirds of the trap. Before initial
when samples containing 1 μg/L of analyte were analyzed use, the trap should be conditioned overnight at 225°C by
immediately after samples containing 20 μg/L of analyte. For backflushing with an inert gas flow of at least 20 mL/min. Vent
that reason, when low concentrations of analytes are measured the trap effluent to the room rather than to the analytical
in a sample, it is very important to examine the results of the column. Prior to daily use, the trap should be conditioned for
preceding samples and interpret the low-concentration results 10 min at 225°C with backflushing. The trap may be vented to
accordingly. One preventive technique is between-sample rins- the analytical column during daily conditioning, provided that
ing of the purging apparatus and sample syringes with two the column is run through the temperature program prior to
7 , 8
portions of reagent water. After analysis of a sample containing analysis of samples.
high concentrations of volatile organic compounds, one or 7.2.2.2 The use of the methyl silicone coated packing is
more laboratory reagent blanks should be analyzed to check for recommended, but not mandatory. The packing serves the
cross contamination. After analyzing a highly contaminated purpose of protecting the Tenax adsorbant from aerosols.
sample, it may be necessary to use methanol to clean the Since it may adsorb higher boiling compounds, it must be fully
sample chamber, followed by heating in an oven at 105°C. enclosed within the heated zone of the trap. Silanized glass
6.3 Samples can be contaminated by diffusion of volatile wool may be used as a spacer at the trap inlet to eliminate
organics through the septum seal into the sample during potential cold spots.
shipment and storage. The analytical and sample storage area 7.2.2.3 The presence of charcoal in the trap may interfere
should be isolated from all atmospheric sources of volatile with the analysis of ketones. When analyzing for ketones, the
organic compounds, otherwise random background levels may charcoal should be eliminated and the polymer increased to fill
result. Since methylene chloride will permeate through PTFE two thirds of the trap, if dichlorodifluoromethane is not being
tubing, all gas chromatography carrier gas lines and purge gas analyzed.
plumbing should be constructed of stainl
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