1、Designation: D 5317 98 (Reapproved 2003)e1Standard Test Method forDetermination of Chlorinated Organic Acid Compounds inWater by Gas Chromatography with an Electron CaptureDetector1This standard is issued under the fixed designation D 5317; the number immediately following the designation indicates
2、the year oforiginal adoption or, in the case of revision, the 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.e1NOTEWarning notes were editorially moved into the standar
3、d text in August 2003.1. Scope1.1 This test method covers a gas chromatographic proce-dure for the quantitative determination of selected chlorinatedacids and other acidic herbicides in water. Similar chemicalsmay also be determined by this test method, but it is the usersresponsibility to verify th
4、e applicability of this test method toany compounds not listed in this scope. The acid form of thefollowing compounds were interlaboratory tested using thistest method, and the results were found acceptable:2Analyte Chemical Abstract ServicesRegistry NumberBentazon 25057-89-02,4-D 94-75-72,4-DB 94-8
5、2-6DCPA acid metabolites2Dicamba 1918-00-93,5-Dichlorobenzoic acid 51-36-5Dichlorprop 120-36-55-Hydroxydicamba 7600-50-2Pentachlorophenol (PCP) 87-86-5Picloram 1918-02-12,4,5-T 93-76-52,4,5-TP (Silvex) 93-72-11.2 This test method may be applicable to the determinationof salts and esters of analyte c
6、ompounds. The form of each acidis not distinguished by this test method. Results are calculatedand reported for each listed analyte as the total free acid.1.3 This test method has been validated in an interlaboratorytest for reagent water and finished tap water. The analyst shouldrecognize that prec
7、ision and bias reported in Section 18 maynot be applicable to other waters.1.4 This test method is restricted to use by or under thesupervision of analysts experienced in the use of gas chroma-tography (GC) and in the interpretation of gas chromatograms.Each analyst must demonstrate the ability to g
8、enerate accept-able results with this test method using the procedure describedin 19.3. It is the users responsibility to ensure the validity ofthis test method for waters of untested matrices.1.5 Analytes that are not separated chromatographically,that is, which have very similar retention times, c
9、annot beindividually identified and measured in the same calibrationmixture or water sample unless an alternate technique foridentification and quantitation exists (16.6, 16.7, and 16.8).1.6 When this test method is used to analyze unfamiliarsamples for any or all of the analytes given in 1.1, analy
10、teidentifications must be confirmed by at least one additionalqualitative technique.1.7 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.8 This standard does not purport to address all of thesafety concerns, if any, associated
11、 with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificwarning statements, see Sections 6, 8, 9, and 10.2. Referenced Documents2.1 ASTM Standards:D
12、1129 Terminology Relating to Water3D 1193 Specification for Reagent Water3D 2777 Practice for Determination of Precision and Bias ofApplicable Methods of Committee D19 on Water3D 3370 Practices for Sampling Water from Closed Con-duits3D 3856 Guide for Good Laboratory Practices in Laborato-ries Engag
13、ed in Sampling and Analysis of Water31This 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 June 10, 2003. Published August 2003. Originallyapprov
14、ed in 1992. Last previous edition approved in 1998 as D 5317 93 (1998).2DCPA monoacid and diacid metabolites are included in the scope of this testmethod; DCPA diacid metabolite is used for validation studies.3Annual Book of ASTM Standards, Vol 11.01.1Copyright ASTM International, 100 Barr Harbor Dr
15、ive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D 4210 Practice for Interlaboratory Quality Control Proce-dures and a Discussion of Reporting Low-Level Data4D 5789 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Organic Constituents52.2 EPA Standard
16、:Method 515.1, Revision 4.0, Methods for the Determinationof Organic Compounds in Drinking Water62.3 OSHA Standard:29 CFR 1910 OSHA Safety and Health Standards, GeneralIndustry73. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D 1129.3.2 Definitions
17、of Terms Specific to This Standard:3.2.1 internal standarda pure analyte(s) added to a solu-tion in known amount(s) and used to measure the relativeresponses of other method analytes and surrogates that arecomponents of the same solution.3.2.1.1 DiscussionThe internal standard must be an ana-lyte th
18、at is not a sample component.3.2.2 surrogate analytea pure analyte(s), which is ex-tremely unlikely to be found in any sample, and which is addedto a sample aliquot in known amount(s) before extraction andis measured with the same procedures used to measure othersample components.3.2.2.1 DiscussionT
19、he purpose of a surrogate analyte is tomonitor method performance with each sample.4. Summary of Test Method4.1 The compounds listed in 1.1, in water samples, areconverted into sodium salts by adjusting the pH to 12 withsodium hydroxide solution (240 g/L) and shaking for 1 h.Extraneous neutral mater
20、ial is removed by extraction withmethylene chloride. The sample is acidified, the acids areextracted with ethyl ether and converted to methyl esters usingdiazomethane. After the excess reagent is removed, the methylesters are determined by capillary column GC using an electroncapture (EC) detector.
21、Other detection systems, such as micro-coulometric and electrolytic conductivity, are not as sensitiveas EC for measurement of chlorinated acid esters but are morespecific and less subject to interferences. A mass spectrometermay also be used as a detector.4.2 This test method provides a magnesium s
22、ilicate8cleanup procedure to aid in the elimination of interferences thatmay be present.5. Significance and Use5.1 Chlorinated phenoxyacid herbicides, and other organicacids are used extensively for weed control. Esters and salts of2,4-D and silvex have been used as aquatic herbicides in lakes,strea
23、ms, and irrigation canals. Phenoxy acid herbicides can betoxic even at low concentrations. For example, the 96 h, TLmfor silvex is 2.4 mg/L for bluegills (1)9. These reasons makeapparent the need for a standard test method for such com-pounds in water.6. Interferences6.1 Method interferences may be
24、caused by contaminants insolvents, reagents, glassware and other sample processingapparatus that lead to discrete artifacts or elevated baselines ingas chromatograms. All reagents and apparatus must be rou-tinely demonstrated to be free from interferences under theconditions of the analysis by runni
25、ng laboratory reagent blanksas described in 19.2.6.1.1 Glassware must be scrupulously cleaned (2). Clean allglassware as soon as possible after use by thoroughly rinsingwith the last solvent used in it. Follow by washing with hotwater and detergent and thoroughly rinsing with dilute acid,tap, and re
26、agent water. Drain dry, and heat in an oven or mufflefurnace at 400C for 1 h. Do not heat volumetric ware.Thorough rinsing with acetone may be substituted for theheating. After drying and cooling, seal and store glassware ina clean environment to prevent any accumulation of dust orother contaminants
27、. Store inverted or capped with aluminumfoil. Thermally stable materials such as PCBs may not beeliminated by this treatment.6.1.2 The use of high purity reagents and solvents helps tominimize interference problems. Purification of solvents bydistillation in all-glass systems may be required. (Warni
28、ngWhen a solvent is purified, stabilizers added by the manufac-turer are removed, thus potentially making the solvent hazard-ous. Also, when a solvent is purified, preservatives added bythe manufacturer are removed, thus potentially reducing theshelf-life.)6.2 The acid forms of the analytes are stro
29、ng organic acidsthat react readily with alkaline substances and can be lostduring sample preparation. Glassware and glass wool must beacid-rinsed with hydrochloric acid (1 + 9) and the sodiumsulfate must be acidified with sulfuric acid prior to use to avoidanalyte loses due to adsorption.6.3 Organic
30、 acids and phenols, especially chlorinated com-pounds, cause the most direct interference with the determina-tion.Alkaline hydrolysis and subsequent extraction of the basicsample removes many chlorinated hydrocarbons and phthalateesters that might otherwise interfere with the electron captureanalysi
31、s.6.4 Interferences by phthalate esters can pose a majorproblem in pesticide analysis when using the ECD. Thesecompounds generally appear in the chromatogram as largepeaks. Common flexible plastics contain varying amounts ofphthalates, which are easily extracted or leached during labo-ratory operati
32、ons. Cross contamination of clean glasswareroutinely occurs when plastics are handled during extractionsteps, especially when solvent-wetted surfaces are handled.4Discontinued. See 2001 Annual Book of ASTM Standards, Vol 11.01.5Discontinued, replaced by D 5847. See 2001 Annual Book of ASTM Standards
33、,Vol 11.01.6EPA/600/4-88/039, 1989, available from Environmental Monitoring SystemsLaboratory, U.S. Environmental Protection Agency, Cincinnati, OH 45268.7Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.8Florisil
34、, a trademark of, and available from, Floridin Co., 2 Gateway Center,Pittsburgh, PA 15222, or its equivalent, has been found satisfactory for this purpose.9The boldface numbers in parentheses refer to the list of references at the end ofthis test method.D 5317 98 (2003)e12Interferences from phthalat
35、es can best be minimized by avoid-ing the use of plastics in the laboratory. Exhaustive purificationof reagents and glassware may be required to eliminatebackground phthalate contamination (3).6.5 Interfering contamination may occur when a samplecontaining low concentrations of analytes is analyzed
36、imme-diately following a sample containing relatively high concen-trations of analytes. Between-sample rinsing of the samplesyringe and associated equipment with methyl-t-butyl-ether(MTBE) can minimize sample cross contamination. Afteranalysis of a sample containing high concentrations of ana-lytes,
37、 one or more injections of MTBE should be made toensure that accurate values are obtained for the next sample.6.6 Matrix interferences may be caused by contaminantsthat are coextracted from the sample. Also, note that allanalytes listed in Table 1 are not resolved from each other onany one column, t
38、hat is, one analyte of interest may be aninterferent for another analyte of interest. The extent of matrixinterferences will vary considerably from source to source,depending upon the water sampled. The procedures in Section16 can be used to overcome many of these interferences.Positive identificati
39、ons should be confirmed. See 16.6, 16.7,and 16.8.6.7 It is important that samples and working standards becontained in the same solvent. The solvent for workingstandards must be the same as the final solvent used in samplepreparation. If this is not the case, chromatographic compara-bility of standa
40、rds to sample may be affected.7. Apparatus and Equipment7.1 Sample BottleBorosilicate amber, 1-L volume withgraduations, fitted with screw caps lined with TFE-fluorocarbon. Protect samples from light. The container mustbe washed and dried as described in 6.1.1 before use tominimize contamination. Ca
41、p liners are cut to fit from sheetsand extracted with methanol overnight prior to use.7.2 Glassware.7.2.1 Separatory funnel, 2000-mL, with TFE-fluorocarbonstopcocks, ground glass or TFE-fluorocarbon stoppers.7.2.2 Tumbler bottle, 1.7-L with TFE-fluorocarbon linedscrew cap. Cap liners are cut to fit
42、from sheets and extractedwith methanol overnight prior to use.7.2.3 Concentrator tube, Kuderna-Danish (K-D), 10 or25-mL, graduated. Calibration must be checked at the volumesemployed in the procedure. Ground-glass stoppers are used toprevent evaporation of extracts.7.2.4 Evaporative flask, K-D, 500-
43、mL. Attach to concentra-tor tube with springs.7.2.5 Snyder column, K-D, three ball macro.7.2.6 Snyder column, K-D, two ball micro.7.2.7 Flask, round bottom, 500-mL with 24/40 ground glassjoint.7.2.8 Vials, glass, 5 to 10-mL capacity with TFE-fluorocarbon lined screw cap.7.3 Boiling Stone, TFE-fluoro
44、carbon.7.4 Water Bath, heated, capable of temperature control(62C). The bath should be used in a hood.7.5 Diazomethane GeneratorAssemble from two 20- by155-mm test tubes, two neoprene rubber stoppers, and a sourceof nitrogen as shown in Fig. 1.7.6 Glass Wool, acid washed and heated at 450C.7.7 Gas C
45、hromatographAnalytical system complete withtemperature programmable GC suitable for use with capillarycolumns and all required accessories including syringes, ana-lytical columns, gases, detector, and stripchart recorder. A datasystem is recommended for measuring peak areas. Table 1 listsretention t
46、imes observed for test method analytes using thecolumns and analytical conditions described below.7.7.1 Column 1 (Primary Column), 30-m long by 0.25-mminside diameter (I.D.) DB-5 bonded fused silica column,0.25-m film thickness. Establish helium carrier gas flow at 30FIG. 1 Gaseous Diazomethane Gene
47、ratorTABLE 1 Retention Times and Estimated Method DetectionLimits for Method AnalytesAnalyte CAS No.Retention TimeA(min)EDLBPrimary Confirmation3,5-Dichlorobenzoicacid51-36-5 18.6 17.7 0.061DCAA (surrogate) 19719-28-9 22.0 14.9 .Dicamba 1918-00-9 22.1 22.6 0.081Dichlorprop 120-36-5 25.0 25.6 0.262,4
48、-D 94-75-7 25.5 27.0 0.2DBOB (int. std.) 10386-84-2 27.5 27.6 .Pentachlorophenol 87-86-5 28.3 27.0 0.0762,4,5-TP 93-72-1 29.7 29.5 0.0755-Hydroxydicamba 7600-50-2 30.0 30.7 0.042,4,5-T 93-76-5 30.5 30.9 0.082,4-DB 94-82-6 32.2 32.2 0.8Bentazon 25057-89-0 33.3 34.6 0.2Picloram 1918-02-1 34.4 37.5 0.1
49、4DCPA acidmetabolitesC. 35.8 37.8 0.02AColumns and analytical conditions are described in 7.7.1 and 7.7.2BEstimated method detection limit, g/L, determined from 7 replicate analysesof a reagent water fortified with analyte at a concentration level yielding signal-to-noise of 5:1. EDL is defined as the standard deviation 3 students t (99 % C.I., n-1degrees of freedom).CDCPA monoacid and diacid metabolites are included in the scope of this testmethod; DCPA diacid metabolite is used for validation studies.D 5317 98 (2003)e13cm/s linear velocity and program oven tempera
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