ASTM D5241-92(2004)
(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
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 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D5241–92(Reapproved 2004)
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 D3973 Test Method for Low-Molecular Weight Haloge-
nated Hydrocarbons in Water
1.1 This practice covers standard procedures for extraction
D4210 Practice for Intralaboratory Quality Control Proce-
of volatile and semi-volatile organic compounds from water
dures and a Discussion on Reporting Low-Level Data
using small volumes of solvents.
D4448 Guide for Sampling Ground-Water Monitoring
1.2 The compounds of interest must have a greater solubil-
Wells
ity in the organic solvent than the water phase.
D5175 Test Method for Organohalide Pesticides and Poly-
1.3 Not all of the solvents that can be used in micro
chlorinated Biphenyls in Water by Microextraction and
extraction are addressed in this practice. The applicability of a
Gas Chromatography
solvent to extract the compound(s) of interest must be demon-
strated before use.
3. Summary of Practice
1.4 This practice provides sample extracts suitable for any
3.1 This practice employs liquid/liquid extraction to isolate
technique amenable to solvent injection such as gas chroma-
compounds of interest. The sample is added to an extraction
tography or high performance liquid chromatography (HPLC).
device.Thesolventmaybeaddedtothesamplecontaineroran
1.5 The values stated in SI units are to be regarded as the
extraction device and extracted for a period of 5 min. The
standard.
solvent is then ready for analysis. If required, the pH may be
1.6 This standard does not purport to address all of the
adjusted and salt may be added prior to extraction to increase
safety concerns, if any, associated with its use. It is the
the extraction specificity and efficiency.
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
2. Referenced Documents practice does not include sample extract clean-up methods.
2.1 ASTM Standards:
4. Significance and Use
D1129 Terminology Relating to Water
4.1 This practice provides a general procedure for the
D1193 Specification for Reagent Water
solvent extraction of volatile and semi-volatile organic com-
D3370 Practices for Sampling Water from Closed Conduits
pounds from a water matrix. Solvent extraction is used as the
D3694 Practices for Preparation of Sample Containers and
initial step in the solvent extraction of organic constituents for
for Preservation of Organic Constituents
the purpose of quantifying extractable organic compounds.
D3856 Guide for Good Laboratory Practices in Laborato-
4.2 Typical detection limits that can be achieved using
ries Engaged in Sampling and Analysis of Water
micro-extraction techniques with gas chromatography (GC)
with flame ionization detector (FID), electron capture detector
This practice is under the jurisdiction ofASTM Committee D19 on Water and
(ECD), or with a mass spectrometer (GC/MS) range from
is the direct responsibility of Subcommittee D19.06 on Methods for Analysis for
milligrams per litre (mg/L) to nanograms per litre (ng/L). The
Organic Substances in Water.
detection limit, linear concentration range, and sensitivity of
Current edition approved June 1, 2004. Published June 2004. Originally
the test method for a specific organic compound will depend
approved in 1992. Last previous edition approved in 1998 as D5241 – 92 (1998).
DOI: 10.1520/D5241-92R04.
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 Withdrawn
Standards volume information, refer to the standard’s Document Summary page on Withdrawn. The last approved version of this historical standard is referenced
the ASTM website. on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5241–92 (2004)
upon the sample clean-up, injection volume, solvent to sample 5.2 When performing analyses for specific organic com-
ratio, solvent concentration methods used, and the determina- pounds, matrix interferences may be caused by materials and
tive technique employed. constituentsthatarecoextractedfromthesample.Theextentof
4.3 Micro-extraction has the advantage of speed, simple such matrix interferences will vary considerably depending on
extraction devices, and the use of small amounts of sample and the sample and the specific instrumental analysis method used.
solvents. Matrix interferences may be reduced by the choice of extract-
4.3.1 Selectivity can be improved by the choice of solvent ing solvent, or by using a clean-up technique on the extract.
(usually hexane or pentane) or mixed solvents, extraction time
and temperature, and ionic strength of the solution.
6. Selection of the Extraction Solvent
4.3.2 Extraction devices can vary from the sample container
6.1 The selection of solvent for extraction will depend upon
itself to commercial devices specifically designed for micro-
many factors, including the following:
extraction. See 7.1 and 7.2.
6.1.1 Solvent compatibility with analytical instrumentation,
4.3.3 A list of chlorinated organic compounds that can be
6.1.2 Solubility of the organic constituent in the solvent
determined by this practice includes both high and low boiling
versus its solubility in water. The water/solvent ratio has been
compounds or chemicals (see Table 1).
found to be critical to achieve optimum recovery of some
analytes (see Test Method D3973). Typical solvent to sample
5. Interferences
ratios are 1 to 10 or 20. The ratio should be optimized for
5.1 Solvents,reagents,glassware,andothersampleprocess-
maximum recovery or detection of an analyte, or both,
ing hardware may yield discrete artifacts or elevated baselines
6.1.3 The availability and purity of the solvent,
that can cause poor precision and accuracy. See Terminology
6.1.4 The boiling point and viscosity of the solvent,
D1129.
6.1.5 The tendency of the solvent and matrix to form
5.1.1 Glassware should be washed with detergent, rinsed
emulsions, and
with water, followed by a rinse with distilled in glass acetone.
6.1.6 Solubility of the solvent in the water.
Final drying is done by air or 103°C oven.Additional cleaning
6.2 The analyst should analyze sample blank using the
steps may be required when the analysis requires levels of
potential solvent and demonstrate a recovery using a spiking
micrograms per litre or below. Once the glassware has been
procedure in the matrix of interest before applying this
cleaned, it should be used immediately or stored wrapped in
procedure for sample analysis.
aluminum foil (shiny side out) or by stretching a sheet of
PTFE-fluorocarbon over the top for storage.
7. Apparatus
5.1.2 Plastics other than PTFE-fluorocarbon should be
7.1 Volumetric Flasks, 110 mL.
avoided. They are a significant source of interference and can
7.2 Liquid/Liquid Extractor.
adsorb some organics.
7.3 Vials, auto sampler with septa and caps. Vials should be
5.1.3 Afield blank prepared from water and carried through
compatiblewiththeautomaticsampleinjectorandshouldhave
sampling, subsequent storage, and handling can serve as a
an internal volume of not greater than 2 mL.
check on sources of interferences from the containers.
7.4 Vial, crimper.
7.5 Bottles, glass narrow mouth with TFE fluorocarbon-
TABLE 1 Results of Flame Ionization Detector (FID) and Electron lined septum screw caps.
A
Capture Detector (ECD) Detectability
7.6 Shaker, wrist.
NOTE—Lowest levels tested.
8. Reagents
FID (µg/L) ECD (ng/L)
8.1 Purity of Water—Unless otherwise indicated, reference
Trichloroethene 2 5
Tetrachloroethene 2 5
towatershallbeunderstoodtomeanreagentwaterconforming
Monochlorobenzene 1 500
to Type II of Specification D1193.
para-Chlorobenzotrifluoride 1 5
8.2 Chromatographic grade solvents that have been distilled
ortho-Chlorobenzotrifluoride 1 5
ortho-Chlorotoluene 1 100
in glass should be used in all tests. Other grades may be used,
meta-Chlorotoluene 1 100
if it is first ascertained that the solvent is of sufficiently high
para-Chlorotoluene 1 100
purity to permit its use without lessening the accuracy of the
1,2,4-Trichlorobenzene 1 5
1,2,3-Trichlorobenzene 1 5
determination.
Hexachlorobutadiene 1 5
8.3 The extraction solvent of choice should be appropriate
1,2,4,5-Tetrachlorobenzene 1 5
for the matrix and compounds of interest. This choice is
Hexachlorocyclopentadiene 2 5
2,4,5-Trichlorophenol 2 100
dependent upon the chemical properties of the organic con-
1,2,3,4-Tetrachlorobenzene 1 5
stituents of interest and the matrix being extracted.
alpha-Hexachlorocyclohexane 1 5
beta-Hexachlorocyclohexane 1 5
Hexachlorobenzene 1 5
gamma-Hexachlorocyclohexane 1 5
delta-Hexachlorocyclohexane 1 5 5
Cassia, available from Baxter, 1430Waukegan Rd., McGaw Park, IL60085, or
A
equivalent, has been found suitable for this purpose.
Based on the injection of chlorinated compounds in pentane solution, taking
Available from J & W Scientific, 91 Blue Ravine Rd., Folsom, CA 95630, or
into consideration the 100:1 concentration of a water sample by the microextrac-
tion technique. equivalent, has been found suitable for this purpose.
D5241–92 (2004)
8.4 The spiking, standard materials and surrogates should 10.4.2 If residual chlorine is present, add sodium thiosulfate
be reagent orACS grade or better. When they are not available as a preservative (30 mg/4 oz bottle).
as reagent grade, they should have an assay of 90 % or better.
NOTE 2—Any reagents added to the sample at the time of collection or
8.5 Hydrochloric Acid (HCl) or Sulfuric Acid Solution—
before analysis must be added to the laboratory blank and standard. See
(H SO ) (1:1 v:v), prepared by slowly adding 50 mLof acid to
11.3.
2 4
50 mL of water.
11. Quality Control
8.6 Sodium Hydroxide Solution (NaOH), prepared by dis-
11.1 Minimum quality control requirements are an initial
solving 40 g NaOH in water and diluting to 100 mL.
demonstration of laboratory capability, analysis of method
8.7 Sodium Sulfate (Na SO ), reagent grade, granular, an-
2 4
blanks, a laboratory fortified blank, a laboratory fortified
hydrous, prepared by heating to 300°C under a flow of
sample matrix and, if available, quality control samples. For a
nitrogen.
general discussion of good laboratory practices, see Guide
NOTE 1—Nitrogen is only required when trace work using ECD is
D3856 and Practice D4210.
required.
11.2 Selectarepresentativespikeconcentration(aboutthree
8.8 Magnesium Sulfate (MgSO ), reagent grade, granular, times the estimated detection limit or expected concentration)
anhydrous, prepared by heating at 400°C for a minimum of 4
for each analyte. Extract according to Section 12 and analyze.
h in a shallow tray to eliminate interfering organics. 11.3 Method blanks must be prepared using reagent grade
8.9 Sodium Chloride (NaCl), reagent grade, granular.
water and contain all the reagents used in sample preservation
8.10 Sodium Thiosulfate—(Na S O ), reagent grade, granu- and preparation. The blanks must be carried through the entire
2 2 3
lar. analytical procedure with the samples. Each time a group of
samples are run that contain different reagents or reagent
9. Hazards concentrations, a new method blank must be run.
11.4 All calibration and quality control standards must be
9.1 The toxicity and carcinogenicity of chemicals used or
extracted using the same reagents, procedures, and conditions
that could be used in this practice have not been precisely
as the samples.
defined. Each chemical should be treated as a potential health
11.5 Precision and bias must be established for each matrix
hazard. Exposure to these chemicals should be minimized.
and laboratory analytical method.
Each laboratory is responsible for maintaining awareness of
11.5.1 Precision should be determined by splitting spiked
OSHA regulations regarding safe handling of chemicals used
samples or analytes in the batch into two equal portions. The
in this practice.
replicate samples should then be extracted and analyzed.
9.2 If using ether solvents, the hazard of peroxides forma-
11.5.2 Bias should be determined in the laboratory by
tion should be considered by testing for the presence of
spiking the samples with the analytes of interest at a concen-
peroxide prior to use.
tration three times the concentration found in the samples or
less.
10. Sample Handling
NOTE 3—The bias may be decreased by keeping the temperature,
10.1 There are many procedures for acquiring representa-
shaking speed and time, ionic strength, and solvent and sample volumes
tive samples of water. The procedure chosen will be site and
constant.
analysis specific. There are several guides and practices for
sampling listed in the ASTM subject index under Sampling- 12. Procedure
Water Applications. Two good sources are Practices D3370
12.1 Remove samples from storage and allow them to
and Guide D4448.
equilibrate to room temperature.
10.2 The recommended sample size is 40 to 100 mL. More
12.2 Remove the container cap from the sample container.
or less sample can be used depending upon the sample
Withdraw and discard a pre-selected volume of sample to
availability, detection limits required, and the expected con-
allow adequate volume for the addition of the solvent and
centration level of the analyte. Forty millilitre VOA vials are
space for adequate mixing during shaking. Five to 10 mL of
commonly used as sampling containers. Head space should be
sample is typically removed from a 40 mL vial.
eliminated if volatiles analysis is required.
12.3 Replace the container cap and weigh the container and
10.3 Sample Storage:
its contents to the nearest 0.1 g. Record the weight for
10.3.1 All samples must be iced or refrigerated to 4°C from
subsequent sample volume determinations (see 12.7). If a
the time of collection until ready for extraction.
commercial device is to be used instead of the sample vessel
10.3.2 Samples should be stored in a clean dry place away
for the extraction,
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