ASTM D5241-92(2011)
(Practice)Standard Practice for Micro-Extraction of Water for Analysis of Volatile and Semi-Volatile Organic Compounds in Water
Standard Practice for Micro-Extraction of Water for Analysis of Volatile and Semi-Volatile Organic Compounds in Water
SIGNIFICANCE AND USE
This practice provides a general procedure for the solvent extraction of volatile and semi-volatile organic compounds from a water matrix. Solvent extraction is used as the initial step in the solvent extraction of organic constituents for the purpose of quantifying extractable organic compounds.
Typical detection limits that can be achieved using micro-extraction techniques with gas chromatography (GC) with flame ionization detector (FID), electron capture detector (ECD), or with a mass spectrometer (GC/MS) range from milligrams per litre (mg/L) to nanograms per litre (ng/L). The detection limit, linear concentration range, and sensitivity of the test method for a specific organic compound will depend upon the sample clean-up, injection volume, solvent to sample ratio, solvent concentration methods used, and the determinative technique employed.
Micro-extraction has the advantage of speed, simple extraction devices, and the use of small amounts of sample and solvents.
Selectivity can be improved by the choice of solvent (usually hexane or pentane) or mixed solvents, extraction time and temperature, and ionic strength of the solution.
Extraction devices can vary from the sample container itself to commercial devices specifically designed for micro-extraction. See 7.1 and 7.2.
SCOPE
1.1 This practice covers standard procedures for extraction of volatile and semi-volatile organic compounds from water using small volumes of solvents.
1.2 The compounds of interest must have a greater solubility in the organic solvent than the water phase.
1.3 Not all of the solvents that can be used in micro extraction are addressed in this practice. The applicability of a solvent to extract the compound(s) of interest must be demonstrated before use.
1.4 This practice provides sample extracts suitable for any technique amenable to solvent injection such as gas chromatography or high performance liquid chromatography (HPLC).
1.5 The values stated in SI units are to be regarded as the standard.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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. For specific hazard statements, see Section 9.
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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
Designation: D5241 − 92 (Reapproved 2011)
Standard Practice for
Micro-Extraction of Water for Analysis of Volatile and Semi-
Volatile Organic Compounds in Water
This standard is issued under the fixed designation D5241; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope D3694 Practices for Preparation of Sample Containers and
for Preservation of Organic Constituents
1.1 This practice covers standard procedures for extraction
D3856 Guide for Management Systems in Laboratories
of volatile and semi-volatile organic compounds from water
Engaged in Analysis of Water
using small volumes of solvents.
D3973 TestMethodforLow-MolecularWeightHalogenated
1.2 The compounds of interest must have a greater solubil-
Hydrocarbons in Water
ity in the organic solvent than the water phase.
D4210 Practice for Intralaboratory Quality Control Proce-
dures and a Discussion on Reporting Low-Level Data
1.3 Not all of the solvents that can be used in micro
extraction are addressed in this practice. The applicability of a (Withdrawn 2002)
D4448 Guide for Sampling Ground-Water MonitoringWells
solvent to extract the compound(s) of interest must be demon-
strated before use. D5175 Test Method for Organohalide Pesticides and Poly-
chlorinated Biphenyls in Water by Microextraction and
1.4 This practice provides sample extracts suitable for any
Gas Chromatography
technique amenable to solvent injection such as gas chroma-
tography or high performance liquid chromatography (HPLC).
3. Summary of Practice
1.5 The values stated in SI units are to be regarded as the
3.1 This practice employs liquid/liquid extraction to isolate
standard.
compounds of interest. The sample is added to an extraction
1.6 The values stated in SI units are to be regarded as device.Thesolventmaybeaddedtothesamplecontaineroran
extraction device and extracted for a period of 5 min. The
standard. No other units of measurement are included in this
standard. solvent is then ready for analysis. If required, the pH may be
adjusted and salt may be added prior to extraction to increase
1.7 This standard does not purport to address all of the
the extraction specificity and efficiency.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.2 The solvent extract may be further processed using
priate safety and health practices and determine the applica- sample clean-up and concentration techniques. The analytes in
bility of regulatory limitations prior to use. For specific hazard
the solvent may be analyzed using instrumental methods for
statements, see Section 9. specific volatile or semivolatile organic compounds. This
practice does not include sample extract clean-up methods.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
4.1 This practice provides a general procedure for the
D1129 Terminology Relating to Water
solvent extraction of volatile and semi-volatile organic com-
D1193 Specification for Reagent Water
pounds from a water matrix. Solvent extraction is used as the
D3370 Practices for Sampling Water from Closed Conduits
initial step in the solvent extraction of organic constituents for
the purpose of quantifying extractable organic compounds.
4.2 Typical detection limits that can be achieved using
This practice is under the jurisdiction ofASTM Committee D19 on Water and
is the direct responsibility of Subcommittee D19.06 on Methods for Analysis for
micro-extraction techniques with gas chromatography (GC)
Organic Substances in Water.
with flame ionization detector (FID), electron capture detector
Current edition approved May 1, 2011. Published June 2011. Originally
(ECD), or with a mass spectrometer (GC/MS) range from
approved in 1992. Last previous edition approved in 2004 as D5241 – 92 (2004).
DOI: 10.1520/D5241-92R11. milligrams per litre (mg/L) to nanograms per litre (ng/L). The
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5241 − 92 (2011)
detection limit, linear concentration range, and sensitivity of 5.1.3 Afield blank prepared from water and carried through
the test method for a specific organic compound will depend sampling, subsequent storage, and handling can serve as a
upon the sample clean-up, injection volume, solvent to sample check on sources of interferences from the containers.
ratio, solvent concentration methods used, and the determina-
5.2 When performing analyses for specific organic
tive technique employed.
compounds, matrix interferences may be caused by materials
4.3 Micro-extraction has the advantage of speed, simple and constituents that are coextracted from the sample. The
extraction devices, and the use of small amounts of sample and extent of such matrix interferences will vary considerably
solvents. depending on the sample and the specific instrumental analysis
4.3.1 Selectivity can be improved by the choice of solvent method used. Matrix interferences may be reduced by the
(usually hexane or pentane) or mixed solvents, extraction time choice of extracting solvent, or by using a clean-up technique
and temperature, and ionic strength of the solution. on the extract.
4.3.2 Extraction devices can vary from the sample container
6. Selection of the Extraction Solvent
itself to commercial devices specifically designed for micro-
6.1 The selection of solvent for extraction will depend upon
extraction. See 7.1 and 7.2.
many factors, including the following:
4.3.3 A list of chlorinated organic compounds that can be
6.1.1 Solvent compatibility with analytical instrumentation,
determined by this practice includes both high and low boiling
6.1.2 Solubility of the organic constituent in the solvent
compounds or chemicals (see Table 1).
versus its solubility in water. The water/solvent ratio has been
5. Interferences
found to be critical to achieve optimum recovery of some
analytes (see Test Method D3973). Typical solvent to sample
5.1 Solvents,reagents,glassware,andothersampleprocess-
ratios are 1 to 10 or 20. The ratio should be optimized for
ing hardware may yield discrete artifacts or elevated baselines
maximum recovery or detection of an analyte, or both,
that can cause poor precision and accuracy. See Terminology
6.1.3 The availability and purity of the solvent,
D1129.
6.1.4 The boiling point and viscosity of the solvent,
5.1.1 Glassware should be washed with detergent, rinsed
6.1.5 The tendency of the solvent and matrix to form
with water, followed by a rinse with distilled in glass acetone.
emulsions, and
Final drying is done by air or 103°C oven.Additional cleaning
6.1.6 Solubility of the solvent in the water.
steps may be required when the analysis requires levels of
micrograms per litre or below. Once the glassware has been
6.2 The analyst should analyze sample blank using the
cleaned, it should be used immediately or stored wrapped in
potential solvent and demonstrate a recovery using a spiking
aluminum foil (shiny side out) or by stretching a sheet of
procedure in the matrix of interest before applying this
PTFE-fluorocarbon over the top for storage.
procedure for sample analysis.
5.1.2 Plastics other than PTFE-fluorocarbon should be
7. Apparatus
avoided. They are a significant source of interference and can
adsorb some organics. 7.1 Volumetric Flasks, 110 mL.
7.2 Liquid/Liquid Extractor.
TABLE 1 Results of Flame Ionization Detector (FID) and Electron
7.3 Vials, auto sampler with septa and caps. Vials should be
A
Capture Detector (ECD) Detectability
compatiblewiththeautomaticsampleinjectorandshouldhave
an internal volume of not greater than 2 mL.
NOTE 1—Lowest levels tested.
FID (µg/L) ECD (ng/L)
7.4 Vial, crimper.
Trichloroethene 2 5
7.5 Bottles, glass narrow mouth with TFE fluorocarbon-
Tetrachloroethene 2 5
Monochlorobenzene 1 500
lined septum screw caps.
para-Chlorobenzotrifluoride 1 5
7.6 Shaker, wrist.
ortho-Chlorobenzotrifluoride 1 5
ortho-Chlorotoluene 1 100
8. Reagents
meta-Chlorotoluene 1 100
para-Chlorotoluene 1 100
8.1 Purity of Water—Unless otherwise indicated, reference
1,2,4-Trichlorobenzene 1 5
1,2,3-Trichlorobenzene 1 5
towatershallbeunderstoodtomeanreagentwaterconforming
Hexachlorobutadiene 1 5
to Type II of Specification D1193.
1,2,4,5-Tetrachlorobenzene 1 5
Hexachlorocyclopentadiene 2 5
8.2 Chromatographic grade solvents that have been distilled
2,4,5-Trichlorophenol 2 100
in glass should be used in all tests. Other grades may be used,
1,2,3,4-Tetrachlorobenzene 1 5
if it is first ascertained that the solvent is of sufficiently high
alpha-Hexachlorocyclohexane 1 5
beta-Hexachlorocyclohexane 1 5
purity to permit its use without lessening the accuracy of the
Hexachlorobenzene 1 5
determination.
gamma-Hexachlorocyclohexane 1 5
delta-Hexachlorocyclohexane 1 5
A
Cassia, available from Baxter, 1430Waukegan Rd., McGaw Park, IL60085, or
Based on the injection of chlorinated compounds in pentane solution, taking into
equivalent, has been found suitable for this purpose.
consideration the 100:1 concentration of a water sample by the microextraction
Available from J & W Scientific, 91 Blue Ravine Rd., Folsom, CA 95630, or
technique.
equivalent, has been found suitable for this purpose.
D5241 − 92 (2011)
8.3 The extraction solvent of choice should be appropriate 10.4.1 Some compounds are susceptible to rapid biological
for the matrix and compounds of interest. This choice is degradation under certain environmental conditions. If biologi-
dependent upon the chemical properties of the organic con- cal activity is expected, adjust the pH of the sample to about 2
stituents of interest and the matrix being extracted. by adding HCl. The constituent of concern must be stable
underacidconditions.Foradditionalinformation,seePractices
8.4 The spiking, standard materials and surrogates should
D3694.
be reagent orACS grade or better. When they are not available
10.4.2 If residual chlorine is present, add sodium thiosulfate
as reagent grade, they should have an assay of 90 % or better.
as a preservative (30 mg/4 oz bottle).
8.5 Hydrochloric Acid (HCl) or Sulfuric Acid Solution—
NOTE 2—Any reagents added to the sample at the time of collection or
(H SO ) (1:1 v:v), prepared by slowly adding 50 mLof acid to
2 4
before analysis must be added to the laboratory blank and standard. See
50 mL of water.
11.3.
8.6 Sodium Hydroxide Solution (NaOH), prepared by dis-
11. Quality Control
solving 40 g NaOH in water and diluting to 100 mL.
8.7 Sodium Sulfate (Na SO ), reagent grade, granular, 11.1 Minimum quality control requirements are an initial
2 4
anhydrous, prepared by heating to 300°C under a flow of demonstration of laboratory capability, analysis of method
nitrogen. blanks, a laboratory fortified blank, a laboratory fortified
sample matrix and, if available, quality control samples. For a
NOTE 1—Nitrogen is only required when trace work using ECD is
general discussion of good laboratory practices, see Guide
required.
D3856 and Practice D4210.
8.8 Magnesium Sulfate (MgSO ), reagent grade, granular,
11.2 Selectarepresentativespikeconcentration(aboutthree
anhydrous, prepared by heating at 400°C for a minimum of 4
times the estimated detection limit or expected concentration)
h in a shallow tray to eliminate interfering organics.
for each analyte. Extract according to Section 12 and analyze.
8.9 Sodium Chloride (NaCl), reagent grade, granular.
11.3 Method blanks must be prepared using reagent grade
8.10 Sodium Thiosulfate—(Na S O ), reagent grade, granu-
2 2 3
water and contain all the reagents used in sample preservation
lar.
and preparation. The blanks must be carried through the entire
analytical procedure with the samples. Each time a group of
9. Hazards
samples are run that contain different reagents or reagent
9.1 The toxicity and carcinogenicity of chemicals used or
concentrations, a new method blank must be run.
that could be used in this practice have not been precisely
11.4 All calibration and quality control standards must be
defined. Each chemical should be treated as a potential health
extracted using the same reagents, procedures, and conditions
hazard. Exposure to these chemicals should be minimized.
as the samples.
Each laboratory is responsible for maintaining awareness of
OSHA regulations regarding safe handling of chemicals used
11.5 Precision and bias must be established for each matrix
in this practice.
and laboratory analytical method.
11.5.1 Precision should be determined by splitting spiked
9.2 If using ether solvents, the hazard of peroxides forma-
samples or analytes in the batch into two equal portions. The
tion should be considered by testing for the presence of
replicate samples should then be extracted and analyzed.
peroxide prior to use.
11.5.2 Bias should be determined in the laboratory by
10. Sample Handling
spiking the samples with the analytes of interest at a concen-
10.1 There are many procedures for acquiring representa- tration three times the concentration found in the samples or
less.
tive samples of water. The procedure chosen will be site and
analysis specific. There are several guides and practices for
NOTE 3—The bias may be decreased by keeping the temperature,
sampling listed in the ASTM subject index under Sampling-
shaking speed and time, ionic strength, and solvent and sample volumes
Water Applications. Two good sources are Practices D3370
constant.
and Guide D4448.
12. Procedure
10.2 The recommended sample size is 40 to 100 mL. More
or less sample can be used depending upon the sample 12.1 Remove samples from storage and allow them to
availability, detection limits required, and the expected con- equilibrate to room temperature.
centration level of the analyte. Forty millilitre VOA vials are
12.2 Remove the container cap from the sample container.
commonly used as sampling containers. Head space should be
Withdraw and discard a pre-selected volume of sample to
eliminated if volatiles analysis is required.
allow adequate volume for the addition of the solvent and
10.3 Sample Storage: space for adequate mixing during shaking. Five to 10 mL of
10.3.1 All samples must be iced or refrigerated to 4°C from sam
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