ASTM D3973-1985(2003) Standard Test Method for Low-Molecular Weight Halogenated Hydrocarbons in Water《水中卤代烃低分子量的试验方法》.pdf

1、Designation: D 3973 85 (Reapproved 2003)Standard Test Method forLow-Molecular Weight Halogenated Hydrocarbons in Water1This standard is issued under the fixed designation D 3973; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the

2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the analysis of drinking water.It is also applicable to many environmental and waste

3、waterswhen adequate validation is included.1.2 This test method covers the determination of halom-ethanes, haloethanes, and some related extractable organoha-lides amenable to gas chromatographic measurement. Theapplicable concentration range for trihalomethanes is from 1 to200 g/L. Detection limits

4、 depend on the compound, matrix,and on the characteristics of the gas chromatographic system.1.3 For compounds not specifically included in the precisionand bias section the analyst should validate the test method bycollecting precision and bias data on actual samples.1.4 Confirmation of component i

5、dentities is obtained byobserving retention times using gas chromatographic columnsof different polarities. When concentrations are sufficientlyhigh (50 g/L) confirmation with halogen specific detectorsor gas chromatography/mass spectrometry (GC/MS) may beused. Confirmation of purgeable compounds at

6、 levels down to1 g/Lcan be obtained using Test Method D 3871 with GC/MSdetection.1.5 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 and health practices and de

7、termine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:D 1129 Terminology Relating to Water2D 1193 Specification for Reagent Water2D 3871 Test Method for Purgeable Organic Compounds inWate

8、r Using Headspace Sampling3E 355 Practice for Gas Chromatography Terms and Rela-tionships43. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D 1129 and Practice E 355.4. Summary of Test Method4.1 This test method employs liquid/liquid extraction toiso

9、late compounds of interest and provide a five-fold concen-tration enhancement prior to measurement.5,6 ,7A5-mLaqueoussample is extracted once with 1 mL of solvent. -L aliquot ofthe extract is analyzed in a gas chromatograph equipped withan electron-capture detector.4.2 Extraction efficiencies with t

10、he 1:5 solvent/sample ratiofor trihalomethanes average above 90 %. To compensate forextraction losses, calibration standards are extracted and ana-lyzed in an identical manner.4.3 The concentration of each component is calculated andreported in micrograms per litre.5. Significance and Use5.1 The inc

11、idental conversion of organic material to triha-lomethanes and other volatile organohalides during chlorina-tion of water is a possible health hazard and is the object ofmuch research. This test method can be used as a rapid, simplemeans for determining many volatile organohalides in raw andprocesse

12、d water.6. Interferences6.1 Volatile compounds that are extractable and responsiveto electron-capture detection may interfere with this testmethod.6.2 Impurities in the extracting solvent can be a source ofinterference. Solvent blanks should be analyzed daily andbefore a new bottle of solvent is use

13、d for the first time.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved Jan. 10, 2003. Published January 2003. Originallyapproved in 1980. Las

14、t previous edition approved in 1995 as D 3973 85 (1995)e1.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 11.02.4Annual Book of ASTM Standards, Vol 14.01.5Mieure, J. P., “A Rapid and Sensitive Method for Determining VolatileOrganohalides in Water,” Journal AWWA, Vol 69,

15、 1977, p. 60.6Richard, J. J., and Junk, G. A., “Liquid Extraction for Rapid Determination ofHalomethanes in Water,” Journal AWWA , Vol 69, 1977, p. 62.7“The Analysis of Trihalomethanes in Drinking Water by Liquid/Liquid Extrac-tion,” U.S. Environmental ProtectionAgency, EMSL, Cincinnati, OH, Sept. 9

16、, 1977.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Whenever interfering compounds are traced to the solvent, anew source of solvent should be obtained. Alternatively,impurities may be removed by distillation, column chromatog-rap

17、hy5or purging with high-purity nitrogen or helium. Thisprocedure is quantitative as long as solvent interference con-tributes less than 10 % to the component concentration in thesample.7. Apparatus7.1 Extraction Vessel, 9-mL (2-dram) vial with aluminumfoil or PTFE-lined caps.7.2 Sample Containers, 4

18、0-mL screw cap vials sealed withPTFE-faced silicone septa.87.3 Micro Syringes, 10, 100-L.7.4 Pipets, 1.0 and 5.0-mL transfer.7.5 Glass-Stoppered Volumetric Flasks, 10 and 100-mL.7.6 Gas Chromatograph, with electron-capture detector.7.7 Columns, either of the following columns have beenfound suitable

19、 for this analysis. See Fig. 1 for chromatograms.If other column conditions are used, it is up to the analyst todemonstrate the precision and bias statements are met bycollecting precision, bias, and recovery data.7.7.1 Nonpolar, 3-mm inside diameter by 2-m long boro-silicate glass packed with 100/1

20、20 mesh support9coated witha methyl silicone liquid phase10and operated at 60C with 45mL/min carrier flow.7.7.2 Polar, 3-mm inside diameter by 2-m long borosilicateglass packed with 100/120 mesh support9coated with a polar813075 vials and 12722 septa, available from Pierce Chemical Co., P.O. Box117,

21、 Rockford, IL 61105, have been found suitable; other sources that are equivalentmay be substituted.9Gas-Chrom Q, available from Applied Science Laboratory, Inc., P.O. Box 440,State College, PA 16801, has been found suitable; other sources that are equivalentmay be substituted.10OV-101, available fro

22、m Ohio Valley Specialty Chemical, Inc., Route 6,Marietta, OH 45750, has been found suitable; other sources that are equivalent maybe substituted.FIG. 1 Chromatograms of StandardsD 3973 85 (2003)2liquid phase such as polyethylene glycol11and operated at50C with 60 mL/min carrier flow.8. Reagents8.1 P

23、urity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Soci-ety,12where such specifications are available. Other gradesmay be

24、 used, provided it is first ascertained that the reagent isof sufficiently high purity to permit its use without lesseningthe accuracy of the determination.8.2 Purity of Water Unless otherwise indicated, Specifi-cation D 1193 reagent water, Type II, will be used in this testmethod. In addition the w

25、ater is made organic-free by passingit through a filter bed containing about 0.4 kg of activatedcarbon (8.3), or using a commercial water purification sys-tem.138.3 Activated Carbon.148.4 Dechlorinating AgentGranular sodium thiosulfate orascorbic acid.8.5 Detergent, suitable for laboratory glassware

26、.8.6 Isooctane, pesticide grade.158.7 Methyl Alcohol, pesticide grade.168.8 Sodium Chloride, granular.8.9 Reference Standards:8.9.1 Bromoform.8.9.2 Bromodichloromethane.178.9.3 Chlorodibromomethane.188.9.4 Chloroform.8.9.5 Tetrachloroethylene.8.9.6 1,1,1-Trichloroethane.8.10 Stock Solutions Prepare

27、a stock solution (2 to 10mg/mL) for each standard as follows:8.10.1 WarningBecause of the toxicity of trihalom-ethanes it is necessary to prepare primary dilutions in a hood.It is further recommended that a NIOSH/MESA-approvedtoxic gas respirator be used when the analyst handles highconcentrations o

28、f such materials.8.10.2 Fill a 10.0-mL ground-glass-stoppered volumetricflask with approximately 9.8 mL of methyl alcohol.8.10.3 Allow the flask to stand unstoppered about 10 min oruntil all alcohol wetted surfaces dry.8.10.4 Weigh the unstoppered flask to the nearest 0.1 mg.8.10.5 Using a 100-L syr

29、inge, immediately add 5 to 25drops of one of the reference standards (8.9) to the flask, thenreweigh. Be sure that the drops fall directly into the alcoholwithout contacting the neck of the flask.8.10.6 Dilute to volume with the alcohol, stopper, then mixby inverting the flask several times.8.10.7 C

30、alculate the concentration in micrograms per mil-lilitre from the net gain in weight.8.10.8 Store the solutions at 4C. Warm to room tempera-ture before use.NOTE 1Standard solutions prepared in methyl alcohol are stable up to4 weeks when stored under these conditions. They should be discardedafter th

31、at time has elapsed.9. Sampling9.1 Sample Vial Preparation:9.1.1 Wash all sample vials and septa in detergent water.Rinse with tap water and finally with water (8.2).9.1.2 Allow the vials and septa to air dry, then place in an105C oven for 1 h and allow to cool in an area known to befree of organics

32、.NOTE 2Do not heat the PTFE septa for extended periods of time (1h) because the silicone layer slowly degrades at 105C.9.1.3 When cool, seal the vials using the septa that will beused for sealing the samples.9.2 Sample PreservationIf residual chlorine is present inthe sample and it is desirable to a

33、rrest the formation ofadditional trihalomethanes after sample collection, add thechemical dechlorinating agent (8.4) to the sample and blanks.Add chemical preservative (2.5 to 3 mg/40 mL) in crystallineform to the empty sample vials just prior to shipping to thesampling site. Also chill the samples

34、to 4C during storage.9.3 Sample CollectionSamples may be collected in asampling vial, requiring transfer to an extraction vial as part ofthe analysis, or directly into the extraction vial already con-taining the extraction solvent. The direct procedure minimizessample handling and may be less prone

35、to chemical alterationor headspace losses. However, it does not permit replicateanalyses unless multiple samples are collected. The procedurerequiring laboratory transfer has been validated by interlabo-ratory testing and is described as follows:9.3.1 Fill the sample vial in such a manner that no ai

36、rbubbles pass through the sample as the vial is filled. Fill thevial to overflowing and place on a level surface. Position thePTFE side of a septum on the convex meniscus and seal thevial by screwing the cap on tightly. Invert the vial and lightlytap the cap on a solid surface. The absence of entrai

37、ned airindicates a successful seal. If bubbles are present, open thebottle, add a few additional drops of water and reseal. Maintainthis seal until analysis.11SP-1000, available from Supelco, Inc., Supelco Park, Bellafonte, PA 16823,has been found suitable; other sources that are equivalent may be s

38、ubstituted.12Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United Stat

39、es Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.13Super Q water system, available from Millipore Corp. Ashby Rd., Bedford,MA 01730, has been found suitable; other sources that are equivalent may besubstituted.14Filtrasorb 200, available from Calgon Co

40、rp., Box 1346, Pittsburgh, PA 15230,has been found suitable; other sources that are equivalent may be substituted.15Pesticide grade, available from Burdick other sources that are equivalent may be substituted.16Pesticide grade, available from Burdick other sources which are equivalent may be substit

41、uted.17Bromodichloromethane, available fromAldrich Chemical Co., Inc., 940 W. St.Paul Ave., Milwaukee, WI 53233, has been found suitable; other sources that areequivalent may be substituted.18Chlorodibromomethane, available from Chemical Service Inc., 1887 LincolnAve., West Chester, PA, has been fou

42、nd suitable; other sources that are equivalentmay be substituted.D 3973 85 (2003)39.3.1.1 If preservative (9.2) has been added to the samplevials, fill with the sample just to overflowing, seal the vial, andshake vigorously for 1 min.9.3.2 Sampling from a Water TapTurn on the water andallow the syst

43、em to flush. When the temperature of the waterhas stabilized, adjust the flow to about 500 mL/min and collectduplicate samples from the flowing stream.9.3.3 Sampling from an Open Body of WaterFill a 1-Lwide-mouth container with sample from a representative area.Immediately fill duplicate sample vial

44、s from the 1-L container.9.3.4 Prepare sample blanks, including the preservative, induplicate at the laboratory by filling and sealing the samplevials with water just prior to shipping to the sampling site. Shipone of the blanks to and from the sampling site along with thesample vials. Store this fi

45、eld blank and the samples from agiven site together. Retain the second blank as a laboratoryblank.9.3.5 Analyze the samples as soon as possible. Store thesamples at 4C for a period not to exceed 15 days.10. Calibration and Standardization10.1 Prepare, from the stock solutions (8.10), a multicom-pone

46、nt secondary dilution mixture containing approximately5000 times the expected water concentration of each compo-nent, using methyl alcohol as the solvent. If the expectedconcentration range is unknown, perform a preliminary range-finding measurement, using an aqueous calibration standard(10.2) conta

47、ining approximately 100 g/L.10.2 Prepare an aqueous calibration standard by injecting 20L of the secondary dilution mixture (10.1) into 100 mL waterin a volumetric flask.NOTE 3Aqueous calibration standards are not stable and should bediscarded after1h(8hifstored with zero headspace).10.3 Each day, e

48、xtract and analyze the aqueous calibrationstandard under conditions identical to the sample procedure.15Record the area for each component for calculating results(12.1).10.4 The analyst must be aware of the linear response rangeof the electron-capture detector. Using aqueous calibrationstandards cov

49、ering a broad concentration range, establish alinear range of the test method. Recheck monthly for eachcompound and the concentration range of interest. Wheneverresponses outside the linear range of the test method areobtained, dilute and reanalyze the sample.11. Procedure11.1 Weigh 1.50 g of sodium chloride into a clean extractionvial (7.1).11.2 Pipet 1.0-mL of isooctane into the vial. Open thesample vial, pipet 5.0 mL of sample into the extraction vial,seal the vial and shake vigorously for 1 min. Let stand until thephases separate (about 30 s.).11.3 Ana