1、Designation: D 5996 05Standard Test Method forMeasuring Anionic Contaminants in High-Purity Water byOn-Line Ion Chromatography1This standard is issued under the fixed designation D 5996; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, 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.1. Scope1.1 This test method covers on-line analysis of high-puritywater by the ion chromatography technique. Thi
3、s test methodis applicable for measuring various anionic contaminants inhigh-purity water, typically in the range of 0.01 to 100 g/L.This test method is used to determine the concentration ofacetate, formate, chloride, fluoride, phosphate, nitrate, andsulfate in a continuously flowing sample. The ra
4、nge of the testmethod is only as good as the reagent water available forpreparing standards. At extremely low concentrations, 1.0g/L, preparing standards is difficult, and extra care must betaken in their preparation. The sample may have to beconditioned from higher pressures and temperatures to con
5、di-tions that are suitable for use by on-line instruments.1.2 Online sample analysis of flowing streams does not lenditself to collaborative studies due to the nature of the sampleand the possibility of contamination that may result fromhandling the sample as part of the collaborative study. There-f
6、ore this standard test method is not based on the results of acollaborative study but is intended to provide the best possibleguidance for doing this type of analysis.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of
7、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:2D 1066 Practice for Sampling SteamD 1129 Terminology Relating to WaterD 1192 Specification for Equipment
8、for Sampling Waterand Steam in Closed ConduitsD 1193 Specification for Reagent WaterD 2777 Practice for the Determination of Precision and Biasof Applicable Test Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 3864 Guide for Continual On-Line Monitoring Sys
9、temsfor Water AnalysisD 4453 Practice for Handling of Ultra-Pure Water SamplesD 5542 Test Methods forTraceAnions in High PurityWaterby Ion ChromatographyD 5810 Guide for Spiking into Aqueous SamplesD 5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis
10、3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 analytical column, na column used to separate theanions of interest.3.2.2 analytical column set, na combination of one ormore guard columns followe
11、d by one or more analyticalcolumns.3.2.3 anion suppressor device, na device that is placedbetween the analytical columns and the detector. Its purpose isto inhibit detector response to the ionic constituents in theeluant, so as to lower the detector background and at the sametime enhance detector re
12、sponse to the ions of interest.3.2.4 breakthrough volume, nthe maximum sample vol-ume that can be passed through a concentrator column beforethe least tightly bound ion of interest is eluted. All of thecolumns in series contribute to the overall capacity of theanalytical column set.3.2.5 concentrato
13、r column, nan ion exchange columnused to concentrate the ions of interest and thereby increasemethod sensitivity.3.2.6 eluant, nthe ionic mobile phase used to transport thesample through the analytical column.3.2.7 guard column, na column used before the analyticalcolumn to protect it from contamina
14、nts, such as particulatematter or ionic species that may chemically foul the resins anddegrade their performance.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.03 on Sampling of Water andWater-Formed Deposits, Surveillan
15、ce of Water, and Flow Measurement of Water.Current edition approved June 1, 2005. Published July 2005. Originally approvedin 1996. Last previous edition approved in 2000 as D 5996 96 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servi
16、ceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.8 ion chromatography, na form of liquid chromatog-ra
17、phy in which ionic constituents are separated by ion ex-change followed by a suitable detection means.3.2.9 resolution, nthe ability of an analytical column toseparate constituents under specific test conditions.4. Summary of Test Method4.1 A continuously flowing sample is injected into theinstrumen
18、t through a sample injection valve. The sample ispumped through a concentrator column where the anions ofinterest are collected on ion-exchange resin. After a suitablevolume of sample has been passed through the concentratorcolumn, sample flow is diverted and an eluant is pumpedthrough the concentra
19、tor column to remove the trapped anions.This eluant then flows through an analytical column set wherethe anions are separated based on the retention characteristic ofeach anion relative to the eluant used. The eluant streamcontaining the anions of interest passes through a suppressordevice where the
20、 cations from the eluant are exchanged forhydrogen ions, converting the anions to their acid form. Afterthe suppressor device, the eluant solution passes through aconductivity detector where the separated anions are detected.Detection limits for the anions are enhanced because the anionsare in the a
21、cid form rather than the salt.4.2 The anions are identified based on the retention time ascompared to known standards. By measuring peak height orarea and comparing the detector response to known standards,the anions can be quantified.5. Significance and Use5.1 In the power-generation industry, high
22、-purity water isused to reduce corrosion from anions, such as sulfate, chloride,and fluoride. These anions are known to be detrimental tomaterials of construction used in steam generators, reactorvessel internals and recirculation piping, heat exchangers,connective piping, and turbines. Most electri
23、c generating plantstry to control these anions to 1.0 g/L in the steam generatorfeed water. Some nuclear power plants have been able tocontrol anion contaminants at less than 0.02 g/L.5.2 These anions and others cause low product yields insemiconductor manufacturing. They are also monitored andcontr
24、olled at similarly low levels as in the electric powerindustry.5.3 Low molecular weight organic acids (acetate, formate,propionate) have been detected in steam generator feed water.These low molecular weight organic materials are believed tobe high-temperature degradation products of chemicals used
25、tocontrol cycle water pH and organic contaminants in cyclemakeup water.5.4 In the semiconductor industry, anion contaminants maycome from the breakdown of low molecular weight organicmaterials by ultraviolet light radiation, which is frequentlyused to produce bacteria-free water. These organic compo
26、undsmay also contribute to low product yield.5.5 The production of high-purity water for process makeupand use frequently employs the use of demineralizers toremove unwanted anion contaminants. Also in the electricpower industry, demineralizers are used in the process streamto maintain low levels of
27、 these contaminants. As such, it isimportant to monitor this process to ensure that water qualitystandards are being met. These processes can be monitored forthe above-mentioned anions.5.6 On-line measurements of these contaminants provide agreater degree of protection of the processes by allowing f
28、orfrequent on-line measurement of these species. Early detectionof contaminant ingress allows for quicker corrective action tolocate, reduce, or eliminate, or combination thereof, the source.Grab samples will not provide the same level of protectionbecause of their intermittent nature and the longer
29、 timerequired to obtain and then analyze the sample.5.7 Additionally, on-line monitoring significantly reducesthe potential for contamination of high-purity water samples, asignificant problem when sampling and testing high-puritywater.6. Interferences6.1 When working with low concentration samples,
30、 blanks,and standards, contamination can be a serious problem. Ex-treme care must be exercised in all phases of this test method.6.2 Improper sample line material or sample lines that havenot been properly conditioned can give results that may not betruly representative of the process stream. Absorp
31、tion/desorption of anions on sample line wall deposits can changeanalytical results. Maintaining a minimum sample flow of 1.8m/s (6 ft/s) will minimize deposit buildup on sample line walls,reducing the potential for absorption/desorption of anions.6.3 A single anion present at a concentration signif
32、icantlyhigher than other anions could mask closely adjacent peaks onthe chromatogram.6.4 Low breakthrough volumes may be experienced whencontinuously monitoring for anions in water that has had its pHraised by ammonia, morpholine, or other additives. Thisinterference can be eliminated by taking the
33、sample from theeffluent of a cation resin column.6.5 Identification of the anion is based on retention time ofthe anion of interest. An interfering anion having the sameretention time as one of the anions of interest will result inerroneously high values for that anion.6.6 When loading a concentrato
34、r column, high concentra-tions of interfering anions may cause low breakthrough vol-umes of other anions. These interfering anions may act as aneluant and displace other anions from the concentrator column.See Annex A1 to determine breakthrough volume. Do not loada sample volume greater than 80 % of
35、 the breakthroughvolume.7. Apparatus7.1 Ion chromatograph with the following components:7.1.1 Eluant Introduction SystemThe wetted portion ofthe eluant pump should be nonmetallic or of a corrosion-resistant metal to prevent contamination of the chromatographycolumns.7.1.2 Sample Injection SystemThe
36、wetted portion of thesample pump should be nonmetallic or of a corrosion-resistantmetal to prevent metal contamination of the chromatographycolumns.7.1.3 Anion Suppressor Device.D59960527.1.4 Conductivity Cell, low dead volume (1 L). Tempera-ture compensated or corrected flow through conductivitydet
37、ector should be capable of measuring conductivity from 0 to1000 S/cm. If temperature controlled conductivity detector isused, temperature control should be at 60.5C or better.7.1.5 Suppressor Device Regenerant SystemSome manu-facturers provide integrated regenerant systems that reduce theconsumption
38、 of eluant. Electrochemical suppressor regenerantsystems can be used, eliminating the need to prepare regener-ant solutions.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of
39、 the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Purity of Wa
40、terUnless otherwise indicated, referenceto water shall be understood to mean reagent water as definedby Specification D 1193 Type 1 and shall contain less than 0.2g/Lof the anions of interest. Freshly prepared water should beused for making the low-level standards used for calibration.Detection limi
41、ts will be limited by the purity of the water andreagents used to make standards. The purity of the water usedshall be checked by the use of Test Methods D 5542.8.3 Prepare eluant for the specific columns used and for theanions of interest in accordance with manufacturers direc-tions.8.4 Prepare reg
42、enerant for the specific suppressor used inaccordance with the manufacturers directions if required.NOTE 1There are numerous combinations of analytical columns,suppressors, eluants, and regenerants that may be used with this method.It is not practicable to list all the combinations. Users should use
43、 theappropriate combination of concentrator column, analytical column,suppressor, eluant, and regenerant to achieve the desired resolution anddetection.8.5 Fluoride Solution, Stock (1.00 mL = 1.00 mg F)Drysodium fluoride at 110C for 2 6 0.5 h and cool in a desiccator.Dissolve 2.210 g of dried salt i
44、n water and dilute to 1 L.8.6 Acetate Solution, Stock (1.00 mL = 1.00 mg acetate)Dissolve 1.389 g of sodium acetate in water and dilute to 1 Lwith water. Store in a brown glass bottle with a TFE-fluorocarbon lined cap in a refrigerator.8.7 Formate Solution, Stock (1.00 mL = 1 mg formate)Dissolve 1.5
45、11 g sodium formate in water and dilute to 1 Lwith water. Store in a brown glass bottle with a TFE-fluorocarbon lined cap in a refrigerator.8.8 Chloride Solution, Stock (1.00 mL = 1.00 mg Cl)Drysodium chloride (NaCl) for 2 6 0.5 h at 110C and cool in adesiccator. Dissolve 1.648 g of the dry salt in
46、water and diluteto1L.8.9 Phosphate Solution, Stock (1.00 mL = 1.00 mg PO4)Dissolve 1.433 g of potassium dihydrogen phosphate (KH2PO4) in water and dilute to 1 L with water.8.10 Sulfate Solution, Stock (1.00 mL = 1.00 mg SO4)Drysodium sulfate for 2 6 0.5 h at 110C and cool in a desiccator.Dissolve 1.
47、479 g of the dried salt in water and dilute to 1 L.8.11 Nitrate Solution, Stock (1.00 mL = 1.00 mg NO3)Dry approximately2gofsodium nitrate (NaNO3) at 105C for48 h. Dissolve exactly 1.371 g of the dried salt in water anddilute to 1 L with water.8.12 Anion Intermediate SolutionsPrepare a 1000 g/Lstand
48、ard of each anion by diluting 1.00 mL of each stocksolution to 1 L. If acetate, formate, or phosphate are includedin the standard, the solution must be prepared daily. It isrecommended that these standards be prepared separately fromthe rest of the anions.8.13 Anion Working SolutionsPrepare a blank
49、and at leastthree different working solutions from the anion intermediatesolution, containing the anions of interest. Prepare in dedicatedvolumetric flasks and transfer to sample containers in accor-dance with Practice D 4453. Prepare fresh daily. The range ofthe working solutions prepared should bracket the analyticalrange of interest. A typical range would be 5, 10, and 25 g/Lfor each anion or consistent with analytical range of interest.Systems equipped with sample preparation modules are ca-pable of automatic standard preparation at signific
