ASTM D5241-92(1998)
(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 problems, 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.
General Information
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
An American National Standard
Designation: D 5241 – 92 (Reapproved 1998)
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 D 5241; 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 D 4210 Practice for Intralaboratory Quality Control Proce-
dures and a Discussion on Reporting Low-Level Data
1.1 This practice covers standard procedures for extraction
D 4448 Guide for Sampling Groundwater Monitoring
of volatile and semi-volatile organic compounds from water
Wells
using small volumes of solvents.
D 5175 Test Method for Organohalide Pesticides and Poly-
1.2 The compounds of interest must have a greater solubil-
chlorinated Biphenyls in Water by Microextraction and
ity in the organic solvent than the water phase.
Gas Chromatography
1.3 Not all of the solvents that can be used in micro
extraction are addressed in this practice. The applicability of a
3. Summary of Practice
solvent to extract the compound(s) of interest must be demon-
3.1 This practice employs liquid/liquid extraction to isolate
strated before use.
compounds of interest. The sample is added to an extraction
1.4 This practice provides sample extracts suitable for any
device. The solvent may be added to the sample container or an
technique amenable to solvent injection such as gas chroma-
extraction device and extracted for a period of 5 min. The
tography or high performance liquid chromatography (HPLC).
solvent is then ready for analysis. If required, the pH may be
1.5 The values stated in SI units are to be regarded as the
adjusted and salt may be added prior to extraction to increase
standard.
the extraction specificity and efficiency.
1.6 This standard does not purport to address all of the
3.2 The solvent extract may be further processed using
safety concerns, if any, associated with its use. It is the
sample clean-up and concentration techniques. The analytes in
responsibility of the user of this standard to establish appro-
the solvent may be analyzed using instrumental methods for
priate safety and health practices and determine the applica-
specific volatile or semivolatile organic compounds. This
bility of regulatory limitations prior to use. For specific hazard
practice does not include sample extract clean-up methods.
statements, see Section 9.
4. Significance and Use
2. Referenced Documents
4.1 This practice provides a general procedure for the
2.1 ASTM Standards:
2 solvent extraction of volatile and semi-volatile organic com-
D 1129 Terminology Relating to Water
2 pounds from a water matrix. Solvent extraction is used as the
D 1193 Specification for Reagent Water
initial step in the solvent extraction of organic constituents for
D 3370 Practices for Sampling Water from Closed Con-
2 the purpose of quantifying extractable organic compounds.
duits
4.2 Typical detection limits that can be achieved using
D 3694 Practices for Preparation of Sample Containers and
3 micro-extraction techniques with gas chromatography (GC)
for Preservation of Organic Constituents
with flame ionization detector (FID), electron capture detector
D 3856 Practice for Evaluating Laboratories Engaged in
(ECD), or with a mass spectrometer (GC/MS) range from
Sampling and Analysis of Water and Wastewater
milligrams per litre (mg/L) to nanograms per litre (ng/L). The
D 3973 Test Method for Low-Molecular Weight Haloge-
detection limit, linear concentration range, and sensitivity of
nated Hydrocarbons in Water
the test method for a specific organic compound will depend
upon the sample clean-up, injection volume, solvent to sample
This practice is under the jurisdiction of ASTM Committee D-19 on Water and ratio, solvent concentration methods used, and the determina-
is the direct responsibility of Subcommittee D19.06 on Methods for Analysis for
tive technique employed.
Organic Substances in Water.
Current edition approved May 15, 1992. Published September 1992.
Annual Book of ASTM Standards, Vol 11.01.
3 4
Annual Book of ASTM Standards, Vol 11.02. Annual Book of ASTM Standards, Vol 11.04.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5241 – 92 (1998)
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 D 3973). Typical solvent to sample
5. Interferences
ratios are 1 to 10 or 20. The ratio should be optimized for
5.1 Solvents, reagents, glassware, and other sample process-
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,
D 1129.
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 A field blank prepared from water and carried through
compatible with the automatic sample injector and should have
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.
5.2 When performing analyses for specific organic com-
7.5 Bottles, glass narrow mouth with TFE fluorocarbon-
pounds, matrix interferences may be caused by materials and
lined septum screw caps.
constituents that are coextracted from the sample. The extent of
7.6 Shaker, wrist.
TABLE 1 Results of Flame Ionization Detector (FID) and Electron 8. Reagents
A
Capture Detector (ECD) Detectability
8.1 Purity of Water—Unless otherwise indicated, reference
NOTE 1—Lowest levels tested. to water shall be understood to mean reagent water conforming
to Type II of Specification D 1193.
FID (μg/L) ECD (ng/L)
8.2 Chromatographic grade solvents that have been distilled
Trichloroethene 2 5
Tetrachloroethene 2 5 in glass should be used in all tests. Other grades may be used,
Monochlorobenzene 1 500
if it is first ascertained that the solvent is of sufficiently high
para-Chlorobenzotrifluoride 1 5
purity to permit its use without lessening the accuracy of the
ortho-Chlorobenzotrifluoride 1 5
ortho-Chlorotoluene 1 100 determination.
meta-Chlorotoluene 1 100
8.3 The extraction solvent of choice should be appropriate
para-Chlorotoluene 1 100
for the matrix and compounds of interest. This choice is
1,2,4-Trichlorobenzene 1 5
1,2,3-Trichlorobenzene 1 5 dependent upon the chemical properties of the organic con-
Hexachlorobutadiene 1 5
stituents of interest and the matrix being extracted.
1,2,4,5-Tetrachlorobenzene 1 5
8.4 The spiking, standard materials and surrogates should
Hexachlorocyclopentadiene 2 5
2,4,5-Trichlorophenol 2 100
be reagent or ACS grade or better. When they are not available
1,2,3,4-Tetrachlorobenzene 1 5
as reagent grade, they should have an assay of 90 % or better.
alpha-Hexachlorocyclohexane 1 5
beta-Hexachlorocyclohexane 1 5
Hexachlorobenzene 1 5
gamma-Hexachlorocyclohexane 1 5
delta-Hexachlorocyclohexane 1 5 5
Cassia, available from Baxter, 1430 Waukegan Rd., McGaw Park, IL 60085, 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.
D 5241 – 92 (1998)
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 mL of acid to
2 4
11.3.
50 mL of water.
8.6 Sodium Hydroxide Solution (NaOH), prepared by dis-
11. Quality Control
solving 40 g NaOH in water and diluting to 100 mL.
11.1 Minimum quality control requirements are an initial
8.7 Sodium Sulfate (Na SO ), reagent grade, granular, an-
2 4
demonstration of laboratory capability, analysis of method
hydrous, prepared by heating to 300°C under a flow of
blanks, a laboratory fortified blank, a laboratory fortified
nitrogen.
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.
D 3856 and Practice D 4210.
11.2 Select a representative spike concentration (about three
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-
2 2 3
and preparation. The blanks must be carried through the entire
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.
9.1 The toxicity and carcinogenicity of chemicals used or
11.4 All calibration and quality control standards must be
that could be used in this practice have not been precisely
extracted using the same reagents, procedures, and conditions
defined. Each chemical should be treated as a potential health
as the samples.
hazard. Exposure to these chemicals should be minimized.
11.5 Precision and bias must be established for each matrix
Each laboratory is responsible for maintaining awareness of
and laboratory analytical method.
OSHA regulations regarding safe handling of chemicals used
11.5.1 Precision should be determined by splitting spiked
in this practice.
samples or analytes in the batch into two equal portions. The
9.2 If using ether solvents, the hazard of peroxides forma-
replicate samples should then be extracted and analyzed.
tion should be considered by testing for the presence of
11.5.2 Bias should be determined in the laboratory by
peroxide prior to use.
spiking the samples with the analytes of interest at a concen-
tration three times the concentration found in the samples or
10. Sample Handling
less.
10.1 There are many procedures for acquiring representa-
NOTE 3—The bias may be decreased by keeping the temperature,
tive samples of water. The procedure chosen will be site and
shaking speed and time, ionic strength, and solvent and sample volumes
analysis specific. There are several guides and practices for
constant.
sampling listed in the ASTM subject index under Sampling-
Water Applications. Two good sources are Practices D 3370
12. Procedure
and Guide D 4448.
12.1 Remove samples from storage and allow them to
10.2 The recommended sample size is 40 to 100 mL. More
equilibrate to room temperature.
or less sample can be used depending upon the sample
12.2 Remove the container cap from the sample container.
availability, detection limits required, and the expected con-
Withdraw and discard a pre-selected volume of sample to
centration level of the analyte. Forty millilitre VOA vials are
allow adequate volume for the addition of the solvent and
commonly used as sampling containers. Head space should be
space for adequate mixing during shaking. Five to 10 mL of
eliminated if volatiles analysis is required.
sample is typically removed from a 40 mL vial.
10.3 Sample Storage:
12.3 Replace the container cap and weigh the container and
10.3.1 All samples must be iced or refrigerated to 4°C from
its contents to the nearest 0.1 g. Record the weight for
the time of collection until ready for extraction.
subsequent sample volume determinations (see 12.7). If a
10.3.2 Samples should be stored in a clean dry place away
commercial device is to be used instead of the sample vessel
from samples containing high concentrations of organics.
for the extraction, make a volumetric transfer of the volume of
10.4 Sample Preservation:
the sample specified by the manufacturer to the extraction
10.4.1 Some compounds are susceptible to rapid biological device and utilize this volume in 13.2, omitting the calculation
d
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.