1、Designation: D5241 92 (Reapproved 2017)Standard Practice forMicro-Extraction of Water for Analysis of Volatile and Semi-Volatile Organic Compounds in Water1This standard is issued under the fixed designation D5241; the number immediately following the designation indicates the year oforiginal adopti
2、on or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers standard procedures for extractionof volatile and sem
3、i-volatile organic compounds from waterusing small volumes of solvents.1.2 The compounds of interest must have a greater solubil-ity in the organic solvent than the water phase.1.3 Not all of the solvents that can be used in microextraction are addressed in this practice. The applicability of asolve
4、nt to extract the compound(s) of interest must be demon-strated before use.1.4 This practice provides sample extracts suitable for anytechnique amenable to solvent injection such as gas chroma-tography or high performance liquid chromatography (HPLC).1.5 The values stated in SI units are to be regar
5、ded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practi
6、ces and deter-mine the applicability of regulatory limitations prior to use.For specific hazard statements, see Section 91.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelo
7、pment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD3370 Practices for Sampling Water from C
8、losed ConduitsD3694 Practices for Preparation of Sample Containers andfor Preservation of Organic ConstituentsD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD3973 Test Method for Low-Molecular Weight HalogenatedHydrocarbons in WaterD4210 Practice for Intralaboratory Qu
9、ality Control Proce-dures and a Discussion on Reporting Low-Level Data(Withdrawn 2002)3D4448 Guide for Sampling Ground-Water Monitoring WellsD5175 Test Method for Organohalide Pesticides and Poly-chlorinated Biphenyls in Water by Microextraction andGas Chromatography3. Summary of Practice3.1 This pr
10、actice employs liquid/liquid extraction to isolatecompounds of interest. The sample is added to an extractiondevice. The solvent may be added to the sample container or anextraction device and extracted for a period of 5 min. Thesolvent is then ready for analysis. If required, the pH may beadjusted
11、and salt may be added prior to extraction to increasethe extraction specificity and efficiency.3.2 The solvent extract may be further processed usingsample clean-up and concentration techniques. The analytes inthe solvent may be analyzed using instrumental methods forspecific volatile or semivolatil
12、e organic compounds. Thispractice does not include sample extract clean-up methods.4. Significance and Use4.1 This practice provides a general procedure for thesolvent extraction of volatile and semi-volatile organic com-pounds from a water matrix. Solvent extraction is used as theinitial step in th
13、e solvent extraction of organic constituents forthe purpose of quantifying extractable organic compounds.4.2 Typical detection limits that can be achieved usingmicro-extraction techniques with gas chromatography (GC)with flame ionization detector (FID), electron capture detector1This practice is und
14、er the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.06 on Methods for Analysis forOrganic Substances in Water.Current edition approved Dec. 15, 2017. Published January 2018. Originallyapproved in 1992. Last previous edition approved in 2011 as D5241
15、 92 (2011).DOI: 10.1520/D5241-92R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved versio
16、n of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization establishe
17、d in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1(ECD), or with a mass spectrometer (GC/MS) range frommilligrams per litre (mg/L) to nanograms per litre (ng/L)
18、. Thedetection limit, linear concentration range, and sensitivity ofthe test method for a specific organic compound will dependupon the sample clean-up, injection volume, solvent to sampleratio, solvent concentration methods used, and the determina-tive technique employed.4.3 Micro-extraction has th
19、e advantage of speed, simpleextraction devices, and the use of small amounts of sample andsolvents.4.3.1 Selectivity can be improved by the choice of solvent(usually hexane or pentane) or mixed solvents, extraction timeand temperature, and ionic strength of the solution.4.3.2 Extraction devices can
20、vary from the sample containeritself to commercial devices specifically designed for micro-extraction. See 7.1 and 7.2.4.3.3 A list of chlorinated organic compounds that can bedetermined by this practice includes both high and low boilingcompounds or chemicals (see Table 1).5. Interferences5.1 Solve
21、nts, reagents, glassware, and other sample process-ing hardware may yield discrete artifacts or elevated baselinesthat can cause poor precision and accuracy. See TerminologyD1129.5.1.1 Glassware should be washed with detergent, rinsedwith water, followed by a rinse with distilled in glass acetone.Fi
22、nal drying is done by air or 103C oven. Additional cleaningsteps may be required when the analysis requires levels ofmicrograms per litre or below. Once the glassware has beencleaned, it should be used immediately or stored wrapped inaluminum foil (shiny side out) or by stretching a sheet ofPTFE-flu
23、orocarbon over the top for storage.5.1.2 Plastics other than PTFE-fluorocarbon should beavoided. They are a significant source of interference and canadsorb some organics.5.1.3 A field blank prepared from water and carried throughsampling, subsequent storage, and handling can serve as acheck on sour
24、ces of interferences from the containers.5.2 When performing analyses for specific organiccompounds, matrix interferences may be caused by materialsand constituents that are coextracted from the sample. Theextent of such matrix interferences will vary considerablydepending on the sample and the spec
25、ific instrumental analysismethod used. Matrix interferences may be reduced by thechoice of extracting solvent, or by using a clean-up techniqueon the extract.6. Selection of the Extraction Solvent6.1 The selection of solvent for extraction will depend uponmany factors, including the following:6.1.1
26、Solvent compatibility with analytical instrumentation,6.1.2 Solubility of the organic constituent in the solventversus its solubility in water. The water/solvent ratio has beenfound to be critical to achieve optimum recovery of someanalytes (see Test Method D3973). Typical solvent to sampleratios ar
27、e 1 to 10 or 20. The ratio should be optimized formaximum recovery or detection of an analyte, or both,6.1.3 The availability and purity of the solvent,6.1.4 The boiling point and viscosity of the solvent,6.1.5 The tendency of the solvent and matrix to formemulsions, and6.1.6 Solubility of the solve
28、nt in the water.6.2 The analyst should analyze sample blank using thepotential solvent and demonstrate a recovery using a spikingprocedure in the matrix of interest before applying thisprocedure for sample analysis.7. Apparatus7.1 Volumetric Flasks, 110 mL.47.2 Liquid/Liquid Extractor.57.3 Vials, au
29、to sampler with septa and caps. Vials should becompatible with the automatic sample injector and should havean internal volume of not greater than 2 mL.7.4 Vial, crimper.7.5 Bottles, glass narrow mouth with TFE fluorocarbon-lined septum screw caps.7.6 Shaker, wrist.8. Reagents8.1 Purity of WaterUnle
30、ss otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Type II of Specification D1193.4Cassia, available from Baxter, 1430 Waukegan Rd., McGaw Park, IL 60085, orequivalent, has been found suitable for this purpose.5Available from J be careful not to include
31、any of the waterphase. Preserve this second vial at 4C for an immediatereanalysis if necessary.12.7 If further extraction is required under different pHconditions (acid neutral or base), carefully remove the remain-ing solvent from the sample, adjust the pH, and add thenecessary fresh solvent volume
32、. Repeat 12.4 and 12.5.12.8 Discard the contents of the sample bottle in an envi-ronmentally safe manner. Shake off the remaining few dropsusing short, brisk wrist movements, replace the cap, and weighthe empty bottle to the nearest 0.1 g.12.9 Analyze the extracts by the appropriate method(s) andcor
33、rect the results for volume according to Section 13.13. Calculation13.1 Calculate the sample volume (Vs) in mL as equal to thenet sample weight in grams as follows:Vs5 grossweight 12.3! 2 tare weight 12.8! (1)NOTE 6Brine samples will require a correction for density if highaccuracy is required. Samp
34、les with a high sediment content should becalculated based on weight to weight.13.2 Calculate the corrected sample concentration as fol-lows:13.2.1 When uncorrected analyte concentration is known:C 5 CiX 1000Vs(2)where:C = concentration in g/L,Ci= uncorrected analyte concentration in g/mL, andVs= vo
35、lume of the sample in mL.13.2.2 When only areas or peak heights are known:C 5 Sc3ArSr3ExVs31000 (3)where:C = concentration, in g/L,Sc= concentration of analyte in the standard, in g/mL,Ar= response in area or peak height of the analyte in thesample,Sr= response in area or peak height of the standard
36、 for theanalyte to be determined,Ex= mL of extract, andVs= volume of sample extracted, in mL.14. Precision and Bias14.1 Precision and bias cannot be determined directly forthis practice. However, this procedure was used in the deter-mination of organohalide pesticides, polychlorinatedbiphenyls, and
37、chlorinated organics. See Test Method D5175.14.2 Precision and bias should be generated in the labora-tory on the parameters of concern.14.3 Precision may be improved by the use of an internalstandard. Where internal standards are utilized, add the internalstandard to the extraction solvent containe
38、r prior to aliquotingthe solvent to the extraction vessel.NOTE 7The results of one laboratory determining chlorinated organ-ics listed in Tables 1-3 are being included as information. A Cassia4volumetric flask containing 100 mLof acidified sample was extracted with1 mL of pentane solvent and analyze
39、d using a gas chromatograph withflame ionization and electron capture detectors. The injection volume was1 L. Note that the bias information determined from the data will beTABLE 2 Recovery Data for Pentane Microextraction of 10 g/LSpiked Field SamplesNOTE 1Based on the Extraction of Six Spiked Wate
40、r SolutionsAverage %Recovery% RelativeStandardDeviationTrichloroethene 69 4Tetrachloroethene 72 4Monochlorobenzene 82 3para-Chlorobenzotrifluoride 68 4ortho-Chlorobenzotrifluoride 76 4ortho-Chlorotoluene 88 4meta-Chlorotoluene 88 4para-Chlorotoluene 88 41,2,4-Trichlorobenzene 91 41,2,3-Trichlorobenz
41、ene 95 4Hexachlorobutadiene 78 41,2,4,5-Tetrachlorobenzene 94 4Hexachlorocyclopentadiene 84 42,4,5-Trichlorophenol 65 91,2,3,4-Tetrachlorobenzene 92 4alpha-Hexachlorocyclohexane 94 5beta-Hexachlorocyclohexane 87 5Hexachlorobenzene 94 6gamma-Hexachlorocyclohexane 96 4delta-Hexachlorocyclohexane 91 5D
42、5241 92 (2017)4greater than would be expected from this practice. The standard was notprocessed through the entire practice, which would minimize the bias ofthe practice.15. Keywords15.1 extraction; microextraction; sample preparation; semi-volatile; volatile; waterASTM International takes no positi
43、on respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility
44、.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM
45、International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address sh
46、own below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-83
47、2-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 3 Summary of Recovery Data for the PentaneMicro
48、extraction of Spiked Field SamplesAAverage %Recovery% RelativeStandardDeviationTrichloroethene 71 6Tetrachloroethene 68 4Monochlorobenzene 85 3para-Chlorobenzotrifluoride 63 5ortho-Chlorobenzotrifluoride 74 2ortho-Chlorotoluene 88 2meta-Chlorotoluene 90 4para-Chlorotoluene 89 21,2,4-Trichlorobenzene
49、 89 51,2,3-Trichlorobenzene 93 5Hexachlorobutadiene 64 161,2,4,5-Tetrachlorobenzene 93 4Hexachlorocyclopentadiene 75 102,4,5-Trichlorophenol 60 61,2,3,4-Tetrachlorobenzene 91 5alpha-Hexachlorocyclohexane 95 2beta-Hexachlorocyclohexane 86 2Hexachlorobenzene 95 2gamma-Hexachlorocyclohexane 97 2delta-Hexachlorocyclohexane 90 3AAverage of five replicate spiked water solutions each at 20, 50, and 100 g/L andsix replicate spiked water solutions at 10 g/L.D5241 92 (2017)5
