1、Designation: D 6581 08Standard Test Methods forBromate, Bromide, Chlorate, and Chlorite in Drinking Waterby Suppressed Ion Chromatography1This standard is issued under the fixed designation D 6581; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This multi
3、-test method covers the determination of theoxyhalideschlorite, bromate, and chlorate, and bromide, inraw water, finished drinking water and bottled (non-carbonated) water by chemically and electrolytically sup-pressed ion chromatography. The ranges tested using thismethod for each analyte were as f
4、ollows:Range SectionsTest Method A:Chemically Suppressed Ion Chromatography8 to 18Chlorite 20 to 500 g/LBromate 5 to 30 g/LBromide 20 to 200 g/LChlorate 20 to 500 g/LTest Method B:Electrolytically Suppressed Ion Chromatography19 to 29Chlorite 20 to 1000 g/LBromate 1 to 30 g/LBromide 20 to 200 g/LChl
5、orate 20 to 1000 g/L1.1.1 The upper limits may be extended by appropriatesample dilution or by the use of a smaller injection volume.Other ions of interest, such as fluoride, chloride, nitrite, nitrate,phosphate, and sulfate may also be determined using thismethod. However, analysis of these ions is
6、 not the object ofthis test method.1.2 It is the users responsibility to ensure the validity ofthese test methods for waters of untested matrices.1.3 This test method is technically equivalent with Part B ofU.S. EPA Method 300.12, titled “The Determination of Inor-ganic Anions in Drinking Water by I
7、on Chromatography”.1.4 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 determine the applica-bility of regulatory limitations prior to
8、use.2. Referenced Documents2.1 ASTM Standards:3D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 3856 Guide for
9、 Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of WaterD 5810 Guide for Spiking into Aqueous SamplesD 5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3. Terminology3.1 DefinitionsFor definition of terms used in the tes
10、tmethods, refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 analytical columnthe ion exchange column used toseparate the ions of interest according to their retentioncharacteristics prior to detection.3.2.2 analytical column seta combination of one or moreguard col
11、umns, followed by one or more analytical columnsused to separate the ions of interest.All of the columns in seriesthen contribute to the overall capacity and resolution of theanalytical column set.3.2.3 eluentthe ionic mobile phase used to transport thesample through the chromatographic system.3.2.4
12、 guard columna column used before the analyticalcolumn to protect it from contaminants, such as particulates orirreversibly retained material.3.2.5 ion chromatographya form of liquid chromatogra-phy in which ionic constituents are separated by ion exchangethen detected by an appropriate detection me
13、ans, typicallyconductance.1These test methods are under the jurisdiction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.05 on InorganicConstituents in Water.Current edition approved Aug. 15, 2008. Published September 2008. Originallyapproved in 2000. Last previou
14、s edition approved in 2005 as D 6581 00 (2005).2U.S. EPA Method 300.1, Cincinnati, OH, 1997.3For 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 S
15、ummary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.6 resolutionthe ability of an analytical column toseparate the method analytes under specific test conditions.3.2.7 suppressor devicean ion exchange b
16、ased device thatis placed between the analytical column set and the conduc-tivity detector. Its purpose is to minimize detector response tothe ionic constituents in the eluent, in order to lower back-ground conductance; and at the same time enhance the con-ductivity detector response of the ions of
17、interest.3.2.7.1 chemical suppressionthe use of an acid solution tothe suppressor in order to suppress the background conductiv-ity.3.2.7.2 electrolytic suppressor deviceelectrolytic suppres-sion is an ion exchange device that is placed between theanalytical column and the conductivity detector. Its
18、 purpose issimilar to a suppressor device, however, it does not requireaddition of acid. Instead the electrolytic suppressor generatesprotons electrolytically and plugs into an electrical powersource on typically located on the chromatography device.4. Significance and Use4.1 The oxyhalides chlorite
19、, chlorate, and bromate areinorganic disinfection by-products (DBPs) of considerablehealth risk concern worldwide. The occurrence of chlorite andchlorate is associated with the use of chlorine dioxide, as wellas hypochlorite solutions used for drinking water disinfection.The occurrence of bromate is
20、 associated with the use of ozonefor disinfection, wherein naturally occurring bromide is oxi-dized to bromate. Bromide is a naturally occurring precursor tothe formation of bromate.5. Reagents and Materials5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise ind
21、icated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to p
22、ermit its use without reducing theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D 1193, Type I. Other reagent water types maybe used, provided it is first ascertained that the water
23、 is ofsufficiently high purity to permit its use without adverselyaffecting the bias and precision of the determination.6. Precautions6.1 These methods address the determination of very lowconcentrations of selected anions. Accordingly, every precau-tion should be taken to ensure the cleanliness of
24、samplecontainers as well as other materials and apparatus that come incontact with the sample.7. Sampling and Sample Preservation7.1 Collect the sample in accordance with Practice D 3370,as applicable.7.2 Immediately upon taking the sample, sparge it with aninert gas (e.g., nitrogen, argon or helium
25、) for 5 minutes toremove active gases such as chlorine dioxide or ozone. Add1.00 mL of EDA Preservation Solution (see 13.3) per 1.000litre of sample to prevent conversion of residual hypochloriteor hypobromite to chlorate or bromate. This also preventsmetal catalyzed conversion of chlorite to chlora
26、te. The oxyha-lides in samples preserved in this manner are stable for at least14 days when stored in amber bottles at 4C.5Test Method AChemically Suppressed Ion Chromatography8. Scope8.1 This test method covers the determination of theoxyhalideschlorite, bromate, and chlorate, and bromide, inraw wa
27、ter, finished drinking water and bottled (non-carbonated) water by chemically suppressed ion chromatogra-phy. The ranges tested using this method for each analyte wereas follows:Chlorite 20 to 500 g/LBromate 5 to 30 g/LBromide 20 to 200 g/LChlorate 20 to 500 g/L8.1.1 The upper limits may be extended
28、 by appropriatesample dilution or by the use of a smaller injection volume.Other ions of interest, such as fluoride, chloride, nitrite, nitrate,phosphate, and sulfate may also be determined using thismethod. However, analysis of these ions is not the object ofthis test method.8.2 It is the users res
29、ponsibility to ensure the validity ofthese test methods for waters of untested matrices.8.3 This test method is technically equivalent with Part B ofU.S. EPA Method 300.16, titled “The Determination of Inor-ganic Anions in Drinking Water by Ion Chromatography”.8.4 This standard does not purport to a
30、ddress 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 determine the applica-bility of regulatory limitations prior to use.9. Summary of Test Method A9.1 Oxyhalides (chlorite, b
31、romate, and chlorate) and bro-mide in raw water, finished drinking water and bottled waterare determined by ion chromatography. A sample (200 L) isinjected into an ion chromatograph and the pumped eluent(sodium carbonate) sweeps the sample through the analyticalcolumn set. Here, anions are separated
32、 from the sample matrixaccording to their retention characteristics, relative to theanions in the eluent.9.1.1 The separated anions in the eluent stream then passthrough a suppressor device, where all cations are exchanged4“Reagent Chemicals, American Chemical Society Specifications,” Am. Chemi-cal
33、Soc., Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see “Analar Standards for Laboratory Chemicals,”by BDH Ltd., Poole, Dorset, U.K., and the “United States Pharmacopoeia.”5Hautman, D. P., and Bolyard, M., J. Chromatography, 602, 1992, 65.6U.S
34、. EPA Method 300.1, Cincinnati, OH, 1997.D6581082for hydronium ions. This converts the eluent to carbonic acid,thus reducing the background conductivity. This process alsoconverts the sample anions to their acid form, thus enhancingtheir conductivity. The eluent stream then passes through aconductiv
35、ity cell, where they are detected. A chromatographicintegrator or appropriate computer-based data system is typi-cally used for data presentation.9.2 The anions are identified based on their retention timescompared to known standards. Quantification is accomplishedby measuring anion peak areas and c
36、omparing them to theareas generated from known standards.10. Interferences10.1 Positive errors can be caused by progressive oxidationof residual hypochlorite and/or hypobromite in the sample tothe corresponding chlorate and bromate. Furthermore, chloritecan also be oxidized to chlorate, causing nega
37、tive errors forchlorite and positive errors for chlorate. These interferences areeliminated by the sample preservation steps outlined in 13.3.Chloride present at 200 mg/L and carbonate present at 300mg/L can interfere with bromate determination. These interfer-ences can be minimized, or eliminated,
38、by the sample pretreat-ment steps outlined in 13.4. Fluoride and low molecular weightmonocarboxylic acids, present at mg/L concentrations, mayinterfere with the quantitation of chlorite and bromate.11. Apparatus11.1 Ion Chromatography ApparatusAnalytical systemcomplete with all required accessories,
39、 including eluent pump,injector, syringes, columns, suppressor, conductivity detector,data system and compressed gasses.11.1.1 Eluent PumpCapable of delivering 0.25 to 5 mL/min of eluent at a pressure of up to 4000 psi.11.1.2 Injection ValveAlow dead-volume switching valvethat will allow the loading
40、 of a sample into a sample loop andsubsequent injection of the loop contents into the eluentstream. A loop size of up to 200 L may be used withoutcompromising the resolution of early eluting peaks, such aschlorite and bromate.11.1.3 Guard ColumnAnion exchange column typicallypacked with the same mat
41、erial used in the analytical column.The purpose of this column is to protect the analytical columnfrom particulate matter and irreversibly retained material.11.1.4 Analytical ColumnAnion exchange column ca-pable of separating the ions of interest from each other, as wellas from other ions which comm
42、only occur in the samplematrix. The separation shall be at least as good as that shownin Fig. 2. The use of 2 mm ID AS9-HC column, in conjunctionwith a 50 L sample loop, may improve the peak shape forearly eluting anions, such as chlorite and bromate.NOTE 1The Analytical Column Set (see 3.2.2) shoul
43、d be able to givebaseline resolution of all anions, even for a 200 L injection containing upto 200 mg/L, each, of common anions, such as chloride, bicarbonate, andsulfate.11.1.5 Suppressor DeviceAsuppressor device based uponcation exchange principles. In this method, a membrane-basedself regeneratin
44、g 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.FIG. 1 Chromatogram of a Standard Containing Low g/L Oxyhalides, and Bromide, in the Presence of Common Inorganic An
45、ions(See Table 1 for Analysis Conditions)D658108311.1.6 Conductivity DetectorA low-volume, flowthrough, temperature stabilized conductivity cell equipped witha meter capable of reading from 0 to 1000 S/cm on a linearscale.11.1.7 Data SystemA chromatographic integrator orcomputer-based data system ca
46、pable of graphically presentingthe detector output signal versus time, as well as presenting theintegrated peak areas.12. Preparation of Apparatus12.1 Set up the ion chromatograph according to the manu-facturers instructions. If an Anion Self Regenerating Suppres-sor is used, operate the device at 1
47、00 mA in the external watermode. The conductivity detector cell should be thermallystabilized at 35C.12.2 The recommended operating conditions for the ionchromatograph are summarized in Table 1.12.3 The detector ranges are variable. Normal operatingranges for quantifying the low level of oxyhalides
48、encounteredin treated drinking water are in the 0.2 to 2 S/cm full scalerange. Choose a range consistent with the concentration rangein the expected samples and with the operating requirements ofthe chromatographic system used.12.4 Equilibrate the chromatographic system by pumpingthe analysis eluent
49、 (see 13.2) through the system until a stablebaseline is obtained (approximately 20 minutes). Typicalbaseline characteristics necessary to obtain the method detec-tion limits required for this analysis are: (1) a backgroundconductance of 20 to 25 S/cm and (2) a peak-to-peak (noise)variation of no greater than 5 nS/cm per minute of monitoredbaseline response.13. Reagents and Materials13.1 Eluent, Concentrate (90.0 mM Sodium Carbonate)Dissolve 9.540 g of sodium carbonate in 1000 mL of water.13.2 Eluent, Analysis (9.0 mM Sodium Carbonate
