ASTM D3871-84(1995)e1
(Test Method)Standard Test Method for Purgeable Organic Compounds in Water Using Headspace Sampling
Standard Test Method for Purgeable Organic Compounds in Water Using Headspace Sampling
SCOPE
1.1 This test method covers the determination of most purgeable organic compounds that boil below 200°C and are less than 2% soluble in water. It covers the low [mu]g/L to low mg/L concentration range (see Section 15 and Appendix X1).
1.2 This test method was developed for the analysis of drinking water. It is also applicable to many environmental and waste waters when validation, consisting of recovering known concentrations of compounds of interest added to representative matrices, is included.
1.3 Volatile organic compounds in water at concentrations above 1000 [mu]g/L may be determined by direct aqueous injection in accordance with Practice D2908.
1.4 It is the user's responsibility to assure the validity of the test method for untested matrices.
1.5 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. Specific precautionary statements are given in 8.5.5.1.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn. Contact ASTM International (www.astm.org) for the latest information.
e1
Designation: D 3871 – 84 (Reapproved 1995)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Purgeable Organic Compounds in Water Using Headspace
Sampling
This standard is issued under the fixed designation D 3871; 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.
e NOTE—Section 16 was added editorially in June 1995.
1. Scope 3.2.1 purgeable organic—any organic material that is re-
moved from aqueous solution under the purging conditions
1.1 This test method covers the determination of most
described in this test method (10.1.1).
purgeable organic compounds that boil below 200°C and are
less than 2 % soluble in water. It covers the low μg/L to low
4. Summary of Test Method
mg/L concentration range (see Section 15 and Appendix X1).
4.1 An inert gas is bubbled through the sample to purge
1.2 This test method was developed for the analysis of
volatile compounds from the aqueous phase. These compounds
drinking water. It is also applicable to many environmental and
are then trapped in a column containing a suitable sorbent.
waste waters when validation, consisting of recovering known
After purging is complete, trapped components are thermally
concentrations of compounds of interest added to representa-
desorbed onto the head of a gas chromatographic column for
tive matrices, is included.
separation and analysis. Measurement is accomplished with an
1.3 Volatile organic compounds in water at concentrations
appropriate detector.
above 1000 μg/L may be determined by direct aqueous
injection in accordance with Practice D 2908.
5. Significance and Use
1.4 It is the user’s responsibility to assure the validity of the
5.1 Purgeable organic compounds, including organohalides,
test method for untested matrices.
have been identified as contaminants in raw and drinking
1.5 This standard does not purport to address all of the
water. These contaminants may be harmful to the environment
safety concerns, if any, associated with its use. It is the
and man. Dynamic headspace sampling is a generally appli-
responsibility of the user of this standard to establish appro-
cable method for concentrating these components prior to gas
priate safety and health practices and determine the applica-
chromatographic analysis (1 to 5). This test method can be
bility of regulatory limitations prior to use. Specific precau-
used to quantitatively determine purgeable organic compounds
tionary statements are given in 8.5.5.1.
in raw source water, drinking water, and treated effluent water.
2. Referenced Documents
2.1 ASTM Standards: 6. Interferences
D 1129 Terminology Relating to Water
6.1 Purgeable compounds that coelute with components of
D 1193 Specification for Reagent Water
interest and respond to the detector will interfere with the
D 2908 Practice for Measuring Volatile Organic Matter in
chromatographic measurement. Likelihood of interference may
Water by Aqueous-Injection Gas Chromatography
be decreased by using dissimilar columns or a more selective
E 355 Practice for Gas Chromatography Terms and Rela-
detector for the chromatographic step.
tionships
7. Apparatus
3. Terminology
7.1 Purging Device—Commercial devices are available for
3.1 Definitions—For definitions of terms used in this test
this analysis. Either commercial apparatus or the equipment
method, refer to Terminology D 1129 and Practice E 355.
described below may be used for this analysis. Devices used
3.2 Description of Term Specific to This Standard:
shall be capable of meeting the precision and bias statements
given in 15.1.
7.1.1 Glass Purging Device having a capacity of 5 mL is
This test method is under the jurisdiction of ASTM Committee D-19 on Water
and is the direct responsibility of Subcommittee D19.06 on Methods for Analysis for
shown in Fig. A1.1. Construction details are given in Annex
Organic Substances in Water.
A1. A glass frit is installed at the base of the sample reservoir
Current edition approved June 29, 1984. Published October 1984. Originally
published as D3871 – 79. Last previous edition D3871 – 79.
Annual Book of ASTM Standards, Vol 11.01.
3 5
Annual Book of ASTM Standards, Vol 11.02. The boldface numbers in parentheses refer to the references at the end of this
Annual Book of ASTM Standards, Vol 14.02. test method.
NOTICE:¬This¬standard¬has¬either¬been¬superseded¬and¬replaced¬by¬a¬new¬version¬or
discontinued.¬Contact¬ASTM¬International¬(www.astm.org)¬for¬the¬latest¬information.¬
D 3871
to allow finely divided gas bubbles to pass through the aqueous bly are used to provide the trap-backflush flow. This entire
sample while the sample is restrained above the frit. The assembly is also used to provide gas flow to operate the
sample reservoir is designed to provide maximum bubble purging device.
contact time and efficient mixing. 7.4 Gas Chromatograph equipped with a suitable detector,
such as flame ionization, electrolytic conductivity, microcou-
7.1.2 Gaseous volumes above the sample reservoir are kept
lometric (halide mode), flame photometric, electron capture, or
to a minimum to provide efficient transfer and yet large enough
mass spectrometer.
to allow sufficient space for foams to disperse. Inlet and exit
7.4.1 The gas chromatographic conditions described below
ports are constructed from 6.4-mm ( ⁄4-in.) outside diameter
are recommended and were used to obtain precision and bias
medium-wall tubing so that leak-free removable connections
data (Section 15). If other column conditions are used, the
can be made using“ finger-tight” compression fittings contain-
analyst must demonstrate that the precision and bias achieved
ing plastic ferrules. The optional foam trap is used to control
are at least as good as that presented in Section 15.
occasional samples that foam excessively.
7.4.2 Column is 2.4 m by 2.4-mm inside diameter stainless
7.2 Trap—A short section of stainless steel or glass tubing is
steel packed with a suitable packing. Glass or nickel columns
packed with a suitable sorbent. Traps should be conditioned
may be required for certain applications. Helium carrier gas
before use (Section 11). While other trap designs and sorbent
flow is 33 mL/min and a flame ionization detector is used.
materials may be used (see Section 12), the trap and sorbent
7.4.3 Chromatograph Oven is held at room temperature
described here are recommended and were used to collect
during trap desorption, then rapidly heated to 60°C and held for
precision and bias data. If another trap design or sorbent
4 min. Finally, the temperature is programmed to 170°C at
material is used, these precision and bias statements should be
8°C/min and held for 12 min or until all compounds have
verified. A suitable trap design is 150 mm long by 3.17-mm
eluted.
outside diameter (2.54-mm inside diameter). The front 100 mm
7.5 Sampling Vials, glass, 45-mL, sealed with PTFE-faced
is packed with 60 to 80 mesh 2,6-diphenyl-p-phenylene oxide
septa. Vial caps must be open-top screw caps to prevent vial
followed by 50 mm of 35 to 60-mesh silica gel. One trap
breakage. The vials, septa, and caps are washed with detergent
design is shown in Fig. A1.2, with details in Annex A1. The
and hot water and rinsed with tap water and organic free water.
body assembly acts as a seal for the exit end of the trap. The
The vials and septa are then heated to 105°C for1hand
modified stem assembly is used to seal the inlet end of the trap
allowed to cool to room temperature in a contaminant-free
when it is not in use.
area. When cool, the vials are sealed with septa, PTFE side
7.3 Desorber consists of a trap heater and an auxiliary
down, and screw capped. Aluminum foil disks may be placed
carrier gas source to backflush the trap at elevated temperatures
between the septa and screw cap to help minimize contamina-
directly onto the gas-chromatographic column. Desorber 1
tion. Vials are maintained in this capped condition until just
(Fig. A1.3 and Annex A1) is dedicated to one gas chromato-
prior to filling with water.
graph, but Desorber 2 can be used as a universal desorber for
7.6 Glass Syringe, 5-mL with two-way syringe valve and
many gas chromatographs with a septum-type liquid-inlet
150 to 200 mm, 20-gage syringe needle.
system.
7.3.1 Desorber 1 is attached directly onto the gas- 8. Reagents and Materials
chromatograph liquid-inlet system after removing the septum
8.1 Purity of Reagents—Reagent grade chemicals shall be
nut, the septum, and the internal injector parts. The modified
used in all tests. Unless otherwise indicated, it is intended that
body assembly is screwed onto the inlet system using the PTFE
all reagents shall conform to the specifications of the Commit-
gasket as a seal. A plug is attached to one of the stem 7
tee on Analytical Reagents of the American Chemical Society.
assemblies.
Other grades may be used, provided it is first ascertained that
7.3.1.1 The assembled parts, simply called “the plug,” are
the reagent is of sufficiently high purity to permit its use
used to seal the desorber whenever the trap is removed to
without lessening the accuracy of the determination.
maintain the flow of carrier gas through the gas-
8.2 Purity of Water—Unless otherwise indicated, Specifica-
chromatographic column.
tion D 1193, Type II, will be used in this test method. Analyze
7.3.1.2 The flow controller, PTFE tubing, and stem assem-
a 5-mL aliquot of this water as described in Section 12 before
bly are used to provide the trap-backflush flow. This entire
preparing standard solutions. If the blank sample produces
assembly also provides gas flow to operate the purging device.
interferences for the compounds of interest, purge it free of
7.3.2 Desorber 2 (Fig. A1.4 and Annex A1) may be at-
volatile contaminants with purge gas (8.9) before using.
tached to any gas chromatograph by piercing the gas- 8.3 Dechlorinating Agent—Granular sodium thiosulfate or
chromatographic liquid-inlet septum with the needle.
ascorbic acid.
7.3.2.1 The desorber is assembled in accordance with Fig.
A1.4 with internal volumes and dead-volume areas held to a
Pierce No. 13075 Screw Cap System Vials and 12722 Tuf-Bond Discs, Pierce
minimum. The heat source is concentrated near the base of the
Chemical Co., Rockford, IL, have been found satisfactory for this application.
desorber so that the internal seals of the body assembly do not
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
become damaged by heat. The use of a detachable needle
listed by the American Chemical Society, see Analar Standards for Laboratory
assembly from a microsyringe makes it easy to replace plugged
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
or dulled needles.
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
7.3.2.2 The flow controller, PTFE tubing, and stem assem- MD.
NOTICE:¬This¬standard¬has¬either¬been¬superseded¬and¬replaced¬by¬a¬new¬version¬or
discontinued.¬Contact¬ASTM¬International¬(www.astm.org)¬for¬the¬latest¬information.¬
D 3871
8.4 Trap Packings —60/80 mesh chromatographic grade 8.9 Purge Gas–Nitrogen or Helium—Take precautions to
2,6-diphenyl-p-phenylene oxide and 35 to 60 mesh silica gel. prevent organic materials that may be present in the purge gas
Other packings may be needed for specific determinations. or laboratory air from contaminating the sample. High-purity
8.5 Stock Solutions—Prepare a stock solution (approxi- purge gases (99.99 %) are desirable. Lower quality gases may
be used if impurities are removed, for example by molecular
mately 2 mg/mL) for each material being measured, as follows:
sieve or low-temperature cold traps, or both.
8.5.1 Fill a 10.0-mL ground glass-stoppered volumetric
flask with approximately 9.8 mL of methyl alcohol.
9. Sampling
8.5.2 Allow the flask to stand unstoppered about 10 min or
until all alcohol wetted surfaces dry. 9.1 If the water has been chlorinated, add 1 to 2 mg of
dechlorinating agent to the sampling vial (7.5) before sam-
8.5.3 Weigh the unstoppered flask to the nearest 0.1 mg.
pling. Whether chlorinated or not, fill the vial to overflowing so
8.5.4 Using a 100-μL syringe, immediately add 6 drops of
that a convex meniscus forms at the top. Place a septum, PTFE
one reference material to the flask, then reweigh. Be sure that
the drops fall directly into the alcohol without contacting the side down, carefully on the opening of the vial, displacing the
excess water. If an aluminum foil disk is to be used, place it
neck of the flask.
over the septum. Then seal the vial with the screw cap and
8.5.5 Dilute to volume, stopper, then mix by inverting the
invert to verify the seal by demonstrating the absence of air
flask several times.
bubbles.
8.5.5.1 Warning—Because the reference materials are
likely to be toxic and volatile, prepare concentrated solutions in
NOTE 2—The sample should be headspace-free at this time. A small
a hood. It is advisable to wear rubber gloves and use an
bubble may form if the vial is stored more than a few hours. Analyze the
approved respirator when handling volatile toxic materials. sample within a few hours if possible. If storage is necessary, maintain the
sample temperature at 0 to 4°C until analyzed. Retighten the screw cap
8.5.6 Calculate the concentration in micrograms per millili-
after the sample is chilled. Storage over charcoal will minimize contami-
tre from the net gain in weight.
nation. Data on compounds tested showed them to be stable for at least 15
8.5.7 Store the solutions at 4°C. Warm to room temperature
days.
before use.
10. Calibration and Standardization
NOTE 1—Standard solutions prepared in methyl alcohol are generally
stable up to 4 weeks when stored under these conditions. Discard them 10.1 Calibrate the system by analyzing replicate aliquots of
after that time has elapsed.
the quality check sample (8.7), to which 5 μL of the internal
standard dosing solution (8.8) have been added, as described in
8.6 Working Standard (approximately 100 μg/mL)—
Section 12. Replicate analyses permit the analyst to determine
Prepare a working standard containing each compound to be
precision for each component.
tested, as follows.
10.1.1 Quantitative purging of each component, although
8.6.1 Fill a 100-mL volumetric flask approximately three
desirable, is not required for
...
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