ASTM D4327-2003 Standard Test Method for Anions in Water by Chemically Suppressed Ion Chromatography《用化学压缩离子色谱法对水中阴离子的标准试验方法》.pdf

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1、Designation: D 4327 03Standard Test Method forAnions in Water by Chemically Suppressed IonChromatography1This standard is issued under the fixed designation D 4327; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r

2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method2covers the sequential determination offluoride, chloride, nitrite, ortho-phosphate, bromide, nitrate,and

3、sulfate ions in water by chemically suppressed ion chro-matography.NOTE 1Order of elution is dependent upon the column used; see Fig.1.1.2 This test method is applicable to drinking and wastewa-ters. The ranges tested for this test method for each anion wereas follows (measured in mg/L):Fluoride 0.2

4、6 to 8.49Chloride 0.78 to 26.0Nitrite-N 0.36 to 12.0Bromide 0.63 to 21.0Nitrate-N 0.42 to 14.0o-Phosphate 0.69 to 23.1Sulfate 2.85 to 95.01.3 It is the users responsibility to ensure the validity of thistest method for other matrices.1.4 Concentrations as low as 0.01 mg/L were determineddepending up

5、on the anions to be quantitated, in single labora-tory work. Utilizing a 50-L sample volume loop and asensitivity of 3 S/cm full scale, the approximate detectionlimits shown in Table 1 can be achieved. If lower detectionlevels are required, the sensitivity may be improved by using alower scale setti

6、ng (100 L). The analyst must assure optimum instrumentperformance to maintain a stable baseline at more sensitiveconductivity full-scale settings.1.5 The upper limit of this test method is dependent upontotal anion concentration and may be determined experimen-tally as described in Annex A1. These l

7、imits may be extendedby appropriate dilution or by use of a smaller injection volume.1.6 Using alternate separator column and eluents may per-mit additional anions such as formate or citrate to be deter-mined. This is not the subject of this test method.1.7 This standard does not purport to address

8、all of thesafety problems, if any, associated 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.2. Referenced Documents2.1 ASTM Standards:D 1066 Practice for

9、 Sampling Steam3D 1129 Terminology Relating to Water3D 1193 Specification for Reagent Water3D 2777 Practice for Determination of Precision and Bias ofApplicable Methods of Committee D-19 on Water31This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibili

10、ty of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved Jan. 10, 2003. Published January 2003. Originallyapproved in 1984. Last previous edition approved in 1997 as D 4327 97.2The following references may be consulted for additional information:Small, H., Stevens, T. S.,

11、 and Bauman, W. C., “Novel Ion Exchange Chromato-graphic Method Using Conductrimetric Detection,” Analytical Chemistry, Vol 47,1975, p. 1801.Stevens, T. S., Turkelson, V. T., and Alve, W. R., “Determination of Anions inBoiler Blow Down Water with Ion Chromatography,” Analytical Chemistry, Vol 49,197

12、7, p. 1176.Sawicki, E., Mulik, J. D., and Witgenstein, E., Editors, Ion ChromatographicAnalysis of Environmental Pollutants, Ann Arbor Science Publishers, Ann Arbor,MI, 1978.Mulik, J. D., and Sawicki, E., Editors, Ion Chromatographic Analysis ofEnvironmental Pollutants, Vol/No. 2,AnnArbor Science Pu

13、blishers,AnnArbor, MI,1979.Weiss, J., Handbook of Ion Chromatography, Dionex Corp., Sunnyvale, CA,1986.Waters Innovative Methods for Anion Analysis, Waters Chromatography Divisionof Millipore, Method A 107 and A 116, 1990.Haddad, P. R., and Jackson, P. E., Ion Chromatography: Principles andApplicati

14、ons, Elsevier Scientific Publishing Co., 1990.3Annual Book of ASTM Standards, Vol 11.01.FIG. 1 Chromatogram Showing Separation Using the AS4AColumn1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, P

15、A 19428-2959, United States.D 3370 Practices for Sampling Water from Closed Con-duits3D 5810 Guide for Spiking into Aqueous Samples3D 5847 Practice for the Writing Quality Control Specifica-tions for Standard Test Methods for Water Analysis33. Terminology3.1 DefinitionsFor definitions of terms used

16、in this testmethod, refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 analytical columnsa combination of one or moreguard columns followed by one or more separator columnsused to separate the ions of interest. It should be rememberedthat all of the columns in serie

17、s contribute to the overallcapacity of the analytical column set.3.2.2 chemical suppressor devicea device that is placedbetween the analytical columns and the detector. Its purpose isto inhibit detector response to the ionic constituents in theeluent, so as to lower the detector background and at th

18、e sametime enhance detector response to the ions of interest.3.2.3 eluentthe ionic mobile phase used to transport thesample through the system.3.2.4 guard columna column used before the separatorcolumn to protect it from contaminants, such as particulatematter or irreversibly retained materials.3.2.

19、5 ion chromatographya form of liquid chromatogra-phy in which ionic constituents are separated by ion exchangefollowed by a suitable detection means.3.2.6 resolutionthe ability of an analytical column toseparate constituents under specific test conditions.3.2.7 separator columnthe ion exchange colum

20、n used toseparate the ions of interest according to their retentioncharacteristics prior to their detection.4. Summary of Test Method4.1 An aliquot of sample is injected into an ion chromato-graph. The sample is pumped through two columns and asuppressor device and into a conductivity detector. The

21、ana-lytical column and the guard column are packed with low-capacity anion exchanger. Ions are separated based on theiraffinity for the exchange sites of the resin. The suppressordevice contains a fiber or membrane based cation exchangerthat is continuously regenerated by a flow of dilute sulfuricac

22、id. The suppressor device reduces the background conduc-tivity of the eluent to a low or negligible level by replacing thecations with the hydrogen ion, thereby converting the anions inthe sample to their corresponding acids. The separated anionsin their acid form are measured using an electrical-co

23、nductivitycell. Anions are identified based on their retention timescompared to known standards. Quantitation is accomplished bymeasuring the peak height or area and comparing it to acalibration curve generated from known standards.5. Significance and Use5.1 Ion chromatography provides for both qual

24、itative andquantitative determination of seven common anions, F,Cl,NO2, HPO42,Br,NO3, and SO42, in the milligram perlitre range from a single analytical operation requiring only afew millilitres of sample and taking approximately 10 to 15min for completion.NOTE 2This test method may be used to deter

25、mine fluoride if its peakis in the water dip by adding one mL of eluent (at 1003 the concentrationin 8.3) to all 100-mL volumes of samples and standards to negate theeffect of the water dip. (See 6.3, and also see 6.4.) The quantitation ofunretained peaks should be avoided.Anions such as low molecul

26、ar weightorganic acids (formate, acetate, propionate, etc.) that are conductivecoelute with fluoride and would bias fluoride quantitation in somedrinking waters and most wastewaters.5.2 Anion combinations such as Cl/Brand NO2/NO3,which may be difficult to distinguish by other analyticalmethods, are

27、readily separated by ion chromatography.6. Interferences6.1 Since chloride and nitrite elute very close together, theyare potential interferents for each other. It is advisable not tohave one of these anions present in a ten-fold excess over theother; that is, Cl/NO2ratios higher than 1:10 or 10:1 i

28、f bothions are to be quantitated.6.2 As with other types of chromatography, if one of thesample components is present at very high levels, it mayinterfere by causing a very large peak on the chromatogramthat could mask other peaks present. This type of interferenceis normally minimized by dilution o

29、f the sample (see AnnexA1) and in some instances may be corrected if the concentra-tion of that anion is of interest. However, care should be takennot to dilute the analyte concentration below its detectablelimit.6.3 Water from the sample injection will cause a negativepeak or dip in the chromatogra

30、m when it elutes, because itsconductivity is less than that of the suppressed eluent. This dipusually occurs before Cl.Any peak of interest eluting near thewater dip must be sufficiently resolved from the dip to beaccurately quantitated. Some suggested techniques for elimi-nation of the water dip ar

31、e described in Appendix X1.6.4 Due to the effect of the water dip and the interference oforganic acids and due to the presence of carbonate ions in theseparator column, the user of this test method is urged to usecaution when determining fluoride (see Note 2). If the userwishes to be certain of good

32、 results and has interfering anionspresent when determining fluoride, the eluent can be dilutedTABLE 1 Approximate Single Laboratory Detection Limits inReagent WaterA,BAnalyte Peak No.RetentionTime, minMDLmg/LFluoride 1 1.2 0.01Chloride 2 1.7 0.02Nitrite-N 3 2.0 0.004Bromide 4 2.9 0.01Nitrate-N 5 3.

33、2 0.002o-Phosphate 6 5.4 0.003Sulfate 7 6.9 0.02AData provided by US EPA/EMSL Laboratory, Cincinnati, OH.BColumn: as specified in 7.1.4.Detector: as specified in 7.1.6.Eluent: as specified in 8.3.Pump rate: 2.0 mL/min.Sample loop: 50 L.D4327032until separation of fluoride and carbonate is accomplish

34、ed.Thiswill cause an increase in retention time for anions such assulfate to elute.7. Apparatus7.1 Ion ChromatographThe ion chromatograph shouldhave the following components assembled, as shown in Fig. 2:47.1.1 Eluent and Regenerant Containers.7.1.2 Eluent Pump, capable of delivering 1 to 3 mL/min o

35、feluent at a pressure of up to 2000 psig.7.1.3 Guard ColumnAnion exchange column, typically ofthe same anion exchange material used in the separatorcolumn. The purpose of this column is to protect the analyticalcolumn from particulate matter and irreversibly retained ma-terials.7.1.4 Analytical Colu

36、mnAnion exchange column capableof separating chloride from the injection void volume, as wellas resolving the anions chloride through sulfate.NOTE 3Any analytical column may be used. However, the usershould be able to achieve the resolution and separation as shown in Fig.1.7.1.5 Suppressor DeviceA s

37、uppressor device based uponcation-exchange principles. In this method a membrane-basedself-regenerating suppressor device was used. An equivalentsuppressor device may be used provided that comparablemethod detection limits are achieved and that adequate base-line stability is attained.7.1.6 Detector

38、A low-volume, flow through, temperature-compensated electrical conductivity cell equipped with a metercapable of reading from 0 to 1000 S/cm on a linear scale.7.1.7 Recorder, Integrator, ComputerAdevice compatiblewith the detector output capable of recording detector responseas a function of time fo

39、r the purpose of measuring peak heightor area.7.1.8 Data SystemAn electronic integrator, such as is usedwith gas and liquid chromatographs, may be used to quantitatepeak area, as well as peak height. The peak area data can beused in the same way peak height is used to quantitate results.Computer and

40、 software.7.1.9 Sample LoopA loop on the injection valve that isdesigned to contain an exact amount of the sample. The mostcommon size is 100 L. The sample volume injected onto theseparator column is controlled by this loop. Use of a larger sizeloop will usually cause peak broadening and a loop size

41、 greaterthan 1 mL may result in column overloading and nonlinearresponse. The chromatogram in Fig. 1 uses a 100-L sizesample loop.7.1.9.1 When injections of volumes larger than the sampleloop size are made, any volume above the sample loop sizegoes to waste. It is considered good technique to flush

42、thesample loop upon injection by injecting 2 to 3 times the sampleloop volume.8. Reagents8.1 Purity 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 o

43、f the American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, refere

44、ncesto water shall be understood to mean reagent water conformingto Specification D 1193, Type II. Column life may be extendedby passing Type II water through a 0.22-m filter prior to use.Freshly prepared water should be used for making the stan-dards intended for calibration. The detection limits o

45、f this testmethod will be limited by the purity of the water and reagentsused to make the standards. The purity of the water may bechecked by use of this test method. Anion concentrations ofless than 0.2 g/L each are typical of this type of water.8.3 EluentDissolve 0.2856 g of sodium bicarbonate (1.

46、7mM) and 0.3816 g of sodium carbonate (1.8 mM) in water anddilute to 2 L with water. Other eluents may also prove to beacceptable, provided they give the proper resolution betweenthe component peaks. This eluent will act as a growth mediafor algae. For this reason the eluent should not be kept forlo

47、nger than one month.NOTE 4Use of other eluents may change the order of elution of theanions from that using the carbonate-bicarbonate eluent.8.4 Fiber or Membrane Suppressor Regenerant SolutionCautiously add 3 mL of H2SO4(sp gr 1.84) to 4 L of water.4Available from Dionex Corp., 1228 Titan Way, Sunn

48、yvale, CA 94086. Anequivalent may be used. Other manufacturers components may provide equivalentdata.5“Reagent Chemicals,American Chemical Society Specifications,”Am. Chemi-cal Soc., Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see “Analar St

49、andards for Laboratory Chemicals,”BDH Ltd., Poole, Dorset, U.K., and the “United States Pharmacopeia.”FIG. 2 Schematic of an Ion ChromatographD43270338.5 Stock Solutions:8.5.1 Bromide Stock Solution (1.00 mL = 1.00 mg Br)Dry approximately2gofsodium bromide (NaBr) for6hat150C and cool in a desiccator. Dissolve 1.2877 g of the driedsalt in water and dilute to 1 L with water.8.5.2 Chloride Stock Solution (1.00 mL = 1.00 mg Cl)Dry sodium chloride (NaCl) for1hat100C and cool in adesiccator. Dissolve 1.648 g of the dry salt in water and