1、Designation: D5996 05 (Reapproved 2009)Standard Test Method forMeasuring Anionic Contaminants in High-Purity Water byOn-Line Ion Chromatography1This standard is issued under the fixed designation D5996; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e case 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.1. Scope1.1 This test method covers on-line analysis of high-puritywater by the ion chromatography
3、 technique. This 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
4、 sample. The range 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 temp
5、eratures to condi-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
6、 study. There-fore 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 theres
7、ponsibility 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:2D1066 Practice for Sampling SteamD1129 Terminology Relating to WaterD1192 Guide for Equipm
8、ent for Sampling Water and Steamin Closed Conduits3D1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3864 Guide for Continual On-Line Monitoring System
9、sfor Water AnalysisD4453 Practice for Handling of Ultra-Pure Water SamplesD5542 Test Methods for TraceAnions in High Purity Waterby Ion ChromatographyD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3. Te
10、rminology3.1 For definitions of terms used in this test method, refer toTerminology D1129.3.2 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 followed by o
11、ne 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 response
12、 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 concentrator colu
13、mn, 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.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct respo
14、nsibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use,On-Line Water Analysis, and Surveillance of Water.Current edition approved Oct. 1, 2009. Published November 2009. Originallyapproved in 1996. Last previous edition appr
15、oved in 2005 as D5996 05. DOI:10.1520/D5996-05R09.2For 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 Summary page onthe ASTM website.3Withdrawn.
16、 The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.7 guard column, na column used before the analyticalcolumn to protect it from contaminants, such
17、as particulatematter or ionic species that may chemically foul the resins anddegrade their performance.3.2.8 ion chromatography, na form of liquid chromatog-raphy in which ionic constituents are separated by ion ex-change followed by a suitable detection means.3.2.9 resolution, nthe ability of an an
18、alytical column toseparate constituents under specific test conditions.4. Summary of Test Method4.1 A continuously flowing sample is injected into theinstrument through a sample injection valve. The sample ispumped through a concentrator column where the anions ofinterest are collected on ion-exchan
19、ge resin. After a suitablevolume of sample has been passed through the concentratorcolumn, sample flow is diverted and an eluant is pumpedthrough the concentrator column to remove the trapped anions.This eluant then flows through an analytical column set wherethe anions are separated based on the re
20、tention characteristic ofeach anion relative to the eluant used. The eluant streamcontaining the anions of interest passes through a suppressordevice where the cations from the eluant are exchanged forhydrogen ions, converting the anions to their acid form. Afterthe suppressor device, the eluant sol
21、ution passes through aconductivity detector where the separated anions are detected.Detection limits for the anions are enhanced because the anionsare in the acid form rather than the salt.4.2 The anions are identified based on the retention time ascompared to known standards. By measuring peak heig
22、ht 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-purity water isused to reduce corrosion from anions, such as sulfate, chloride,and fluoride. These anions are known to be detrimental tomate
23、rials of construction used in steam generators, reactorvessel internals and recirculation piping, heat exchangers,connective piping, and turbines. Most electric generating plantstry to control these anions to 1.0 g/L in the steam generatorfeed water. Some nuclear power plants have been able tocontro
24、l 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 andcontrolled at similarly low levels as in the electric powerindustry.5.3 Low molecular weight organic acids (acetate, formate,propionate) have been
25、 detected in steam generator feed water.These low molecular weight organic materials are believed tobe high-temperature degradation products of chemicals used tocontrol cycle water pH and organic contaminants in cyclemakeup water.5.4 In the semiconductor industry, anion contaminants maycome from the
26、 breakdown of low molecular weight organicmaterials by ultraviolet light radiation, which is frequentlyused to produce bacteria-free water. These organic compoundsmay also contribute to low product yield.5.5 The production of high-purity water for process makeupand use frequently employs the use of
27、demineralizers toremove unwanted anion contaminants. Also in the electricpower industry, demineralizers are used in the process streamto maintain low levels of these contaminants. As such, it isimportant to monitor this process to ensure that water qualitystandards are being met. These processes can
28、 be monitored forthe above-mentioned anions.5.6 On-line measurements of these contaminants provide agreater degree of protection of the processes by allowing forfrequent on-line measurement of these species. Early detectionof contaminant ingress allows for quicker corrective action tolocate, reduce,
29、 or eliminate, or combination thereof, the source.Grab samples will not provide the same level of protectionbecause of their intermittent nature and the longer timerequired to obtain and then analyze the sample.5.7 Additionally, on-line monitoring significantly reducesthe potential for contamination
30、 of high-purity water samples, asignificant problem when sampling and testing high-puritywater.6. Interferences6.1 When working with low concentration samples, 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
31、 sample line material or sample lines that havenot been properly conditioned can give results that may not betruly representative of the process stream. Absorption/desorption of anions on sample line wall deposits can changeanalytical results. Maintaining a minimum sample flow of 1.8m/s (6 ft/s) wil
32、l minimize deposit buildup on sample line walls,reducing the potential for absorption/desorption of anions.6.3 A single anion present at a concentration significantlyhigher than other anions could mask closely adjacent peaks onthe chromatogram.6.4 Low breakthrough volumes may be experienced whencont
33、inuously monitoring for anions in water that has had its pHraised by ammonia, morpholine, or other additives. Thisinterference can be eliminated by taking the sample from theeffluent of a cation resin column.6.5 Identification of the anion is based on retention time ofthe anion of interest. An inter
34、fering 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 concentrator column, high concentra-tions of interfering anions may cause low breakthrough vol-umes of other anions. These interfering anions may act as
35、 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 the breakthroughvolume.7. Apparatus7.1 Ion chromatograph with the following components:7.1.1 Eluant Introduction SystemThe wetted portion of
36、the eluant pump should be nonmetallic or of a corrosion-resistant metal to prevent contamination of the chromatographycolumns.D5996 05 (2009)27.1.2 Sample Injection SystemThe wetted portion of thesample pump should be nonmetallic or of a corrosion-resistantmetal to prevent metal contamination of the
37、 chromatographycolumns.7.1.3 Anion Suppressor Device.7.1.4 Conductivity Cell, low dead volume (1 L). Tempera-ture compensated or corrected flow through conductivitydetector should be capable of measuring conductivity from 0 to1000 S/cm. If temperature controlled conductivity detector isused, tempera
38、ture control should be at 60.5C or better.7.1.5 Suppressor Device Regenerant SystemSome manu-facturers provide integrated regenerant systems that reduce theconsumption of eluant. Electrochemical suppressor regenerantsystems can be used, eliminating the need to prepare regener-ant solutions.8. Reagen
39、ts8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be use
40、d,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 WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water as definedby Specification D1193 Type 1 an
41、d 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 limits will be limited by the purity of the water andreagents used to make standards. The purity of the water usedshall be checked by the
42、use of Test Methods D5542.8.3 Prepare eluant for the specific columns used and for theanions of interest in accordance with manufacturers direc-tions.8.4 Prepare regenerant for the specific suppressor used inaccordance with the manufacturers directions if required.NOTE 1There are numerous combinatio
43、ns 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 theappropriate combination of concentrator column, analytical column,suppressor, eluant, and regenerant to achieve the desired resolut
44、ion 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 in 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
45、 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 1.511 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 refriger
46、ator.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 water and diluteto1L.8.9 Phosphate Solution, Stock (1.00 mL = 1.00 mg PO4)Dissolve 1.433 g of potassium dihydrogen phosphate (KH2PO4) i
47、n 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 1.479 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 nitr
48、ate (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/Lstandard of each anion by diluting 1.00 mL of each stocksolution to 1 L. If acetate, formate, or phosphate are includedin the standard, the
49、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 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 D4453. 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
