1、Designation: D5996 05 (Reapproved 2009)D5996 16Standard 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 o
2、r, in the 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-purity water by the ion chrom
3、atography technique. This test method isapplicable for measuring various anionic contaminants in high-purity water, typically in the range of 0.01 to 100 g/L. This testmethod is used to determine the concentration of acetate, formate, chloride, fluoride, phosphate, nitrate, and sulfate in acontinuou
4、sly flowing sample. The range of the test method is only as good as the reagent water available for preparing standards.At extremely low concentrations, 1.0 g/L, preparing standards is difficult, and extra care must be taken in their preparation. Thesample may have to be conditioned from higher pres
5、sures and temperatures to conditions that are suitable for use by on-lineinstruments.1.2 Online sample analysis of flowing streams does not lend itself to collaborative studies due to the nature of the sample andthe possibility of contamination that may result from handling the sample as part of the
6、 collaborative study. Therefore this standardtest method is not based on the results of a collaborative study but is intended to provide the best possible guidance for doing thistype of analysis.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are inclu
7、ded in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to
8、use.2. Referenced Documents2.1 ASTM Standards:2D1066 Practice for Sampling SteamD1129 Terminology Relating to WaterD1192 Guide for Equipment for Sampling Water and Steam in Closed Conduits (Withdrawn 2003)3D1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias of
9、 Applicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3864 Guide for On-Line Monitoring Systems for Water AnalysisD4453 Practice for Handling of High Purity Water SamplesD5542 Test Methods for Trace Anions in High Purity Water by Ion Chromatography
10、D5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis3. Terminology3.1 For definitions of terms used in this test method, refer to Terminology D1129.3.1 Definitions:3.1.1 For definitions of terms used in thi
11、s standard, refer to Terminology D1129.1 This test method is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use, On-Line Water Analysis, and S
12、urveillance of Water.Current edition approved Oct. 1, 2009Feb. 15, 2016. Published November 2009June 2016. Originally approved in 1996. Last previous edition approved in 20052009 asD5996 05.D5996 05 (2009). DOI: 10.1520/D5996-05R09.10.1520/D5996-16.2 For referencedASTM standards, visit theASTM websi
13、te, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an AS
14、TM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In a
15、ll cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 Defin
16、itions of Terms Specific to This Standard:3.2.1 analytical column, na column used to separate the anions of interest.3.2.2 analytical column set, na combination of one or more guard columns followed by one or more analytical columns.3.2.3 anion suppressor device, na device that is placed between the
17、 analytical columns and the detector. Its purpose is toinhibit detector response to the ionic constituents in the eluant, so as to lower the detector background and at the same time enhancedetector response to the ions of interest.3.2.3.1 DiscussionIts purpose is to inhibit detector response to the
18、ionic constituents in the eluant, so as to lower the detector background and at thesame time enhance detector response to the ions of interest.3.2.4 breakthrough volume, nthe maximum sample volume that can be passed through a concentrator column before the leasttightly bound ion of interest is elute
19、d. All of the columns in series contribute to the overall capacity of the analytical column set.3.2.4.1 DiscussionAll of the columns in series contribute to the overall capacity of the analytical column set.3.2.5 concentrator column, nan ion exchange column used to concentrate the ions of interest a
20、nd thereby increase methodsensitivity.3.2.6 eluant, nthe ionic mobile phase used to transport the sample through the analytical column.3.2.7 guard column, na column used before the analytical column to protect it from contaminants, such as particulate matteror ionic species that may chemically foul
21、the resins and degrade their performance.3.2.8 ion chromatography, na form of liquid chromatography in which ionic constituents are separated by ion exchangefollowed by a suitable detection means.3.2.9 resolution, nthe ability of an analytical column to separate constituents under specific test cond
22、itions.4. Summary of Test Method4.1 A continuously flowing sample is injected into the instrument through a sample injection valve. The sample is pumpedthrough a concentrator column where the anions of interest are collected on ion-exchange resin.After a suitable volume of samplehas been passed thro
23、ugh the concentrator column, sample flow is diverted and an eluant is pumped through the concentratorcolumn to remove the trapped anions. This eluant then flows through an analytical column set where the anions are separated basedon the retention characteristic of each anion relative to the eluant u
24、sed. The eluant stream containing the anions of interest passesthrough a suppressor device where the cations from the eluant are exchanged for hydrogen ions, converting the anions to their acidform. After the suppressor device, the eluant solution passes through a conductivity detector where the sep
25、arated anions aredetected. Detection limits for the anions are enhanced because the anions are in the acid form rather than the salt.4.2 The anions are identified based on the retention time as compared to known standards. By measuring peak height or areaand comparing the detector response to known
26、standards, the anions can be quantified.5. Significance and Use5.1 In the power-generation industry, high-purity water is used to reduce corrosion from anions, such as sulfate, chloride, andfluoride. These anions are known to be detrimental to materials of construction used in steam generators, reac
27、tor vessel internalsand recirculation piping, heat exchangers, connective piping, and turbines. Most electric generating plants try to control theseanions to 1.0 g/L in the steam generator feed water. Some nuclear power plants have been able to control anion contaminantsat less than 0.02 g/L.5.2 The
28、se anions and others cause low product yields in semiconductor manufacturing. They are also monitored and controlledat similarly low levels as in the electric power industry.5.3 Low molecular weight organic acids (acetate, formate, propionate) have been detected in steam generator feed water. Thesel
29、ow molecular weight organic materials are believed to be high-temperature degradation products of chemicals used to controlcycle water pH and organic contaminants in cycle makeup water.5.4 In the semiconductor industry, anion contaminants may come from the breakdown of low molecular weight organicma
30、terials by ultraviolet light radiation, which is frequently used to produce bacteria-free water. These organic compounds may alsocontribute to low product yield.5.5 The production of high-purity water for process makeup and use frequently employs the use of demineralizers to removeunwanted anion con
31、taminants. Also in the electric power industry, demineralizers are used in the process stream to maintain lowD5996 162levels of these contaminants. As such, it is important to monitor this process to ensure that water quality standards are being met.These processes can be monitored for the above-men
32、tioned anions.5.6 On-line measurements of these contaminants provide a greater degree of protection of the processes by allowing for frequenton-line measurement of these species. Early detection of contaminant ingress allows for quicker corrective action to locate, reduce,or eliminate, or combinatio
33、n thereof, the source. Grab samples will not provide the same level of protection because of theirintermittent nature and the longer time required to obtain and then analyze the sample.5.7 Additionally, on-line monitoring significantly reduces the potential for contamination of high-purity water sam
34、ples, asignificant problem when sampling and testing high-purity water.6. Interferences6.1 When working with low concentration samples, blanks, and standards, contamination can be a serious problem. Extremecare must be exercised in all phases of this test method.6.2 Improper sample line material or
35、sample lines that have not been properly conditioned can give results that may not be trulyrepresentative of the process stream. Absorption/desorption of anions on sample line wall deposits can change analytical results.Maintaining a minimum sample flow of 1.8 m/s (6 ft/s) will minimize deposit buil
36、dup on sample line walls, reducing the potentialfor absorption/desorption of anions.6.3 A single anion present at a concentration significantly higher than other anions could mask closely adjacent peaks on thechromatogram.6.4 Low breakthrough volumes may be experienced when continuously monitoring f
37、or anions in water that has had its pH raisedby ammonia, morpholine, or other additives. This interference can be eliminated by taking the sample from the effluent of a cationresin column.6.5 Identification of the anion is based on retention time of the anion of interest.An interfering anion having
38、the same retentiontime as one of the anions of interest will result in erroneously high values for that anion.6.6 When loading a concentrator column, high concentrations of interfering anions may cause low breakthrough volumes ofother anions. These interfering anions may act as an eluant and displac
39、e other anions from the concentrator column. See AnnexA1 to determine breakthrough volume. Do not load a sample volume greater than 80 % of the breakthrough volume.7. Apparatus7.1 Ion chromatograph with the following components:7.1.1 Eluant Introduction SystemThe wetted portion of the eluant pump sh
40、ould be nonmetallic or of a corrosion-resistantmetal to prevent contamination of the chromatography columns.7.1.2 Sample Injection SystemThe wetted portion of the sample pump should be nonmetallic or of a corrosion-resistant metalto prevent metal contamination of the chromatography columns.7.1.3 Ani
41、on Suppressor Device.7.1.4 Conductivity Cell, low dead volume (1 L). Temperature compensated or corrected flow through conductivity detectorshould be capable of measuring conductivity from 0 to 1000 S/cm. If temperature controlled conductivity detector is used,temperature control should be at 60.5C
42、or better.7.1.5 Suppressor Device Regenerant SystemSome manufacturers provide integrated regenerant systems that reduce theconsumption of eluant. Electrochemical suppressor regenerant systems can be used, eliminating the need to prepare regenerantsolutions.8. Reagents8.1 Purity of ReagentsReagent gr
43、ade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where suchspecifications are available.4 Other grades may be used, provided it is first ascerta
44、ined that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, reference to water shall be understood to mean reagent water as defined bySpecification D1193 Type 1 and shall contain less than 0.
45、2 g/L of the anions of interest. Freshly prepared water should be usedfor making the low-level standards used for calibration. Detection limits will be limited by the purity of the water and reagentsused to make standards. The purity of the water used shall be checked by the use of Test Methods D554
46、2.8.3 Prepare eluant for the specific columns used and for the anions of interest in accordance with manufacturers directions.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American
47、 Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D5996 1638.4 Prepare regenerant for the specific suppressor used in accordance with the
48、 manufacturers directions if required.NOTE 1There are numerous combinations of analytical columns, suppressors, eluants, and regenerants that may be used with this test method. It isnot practicable to list all the combinations. Users should use the appropriate combination of concentrator column, ana
49、lytical column, suppressor, eluant,and regenerant to achieve the desired resolution and detection.8.5 Fluoride Solution, Stock (1.00 mL = 1.00 mg F)Dry sodium 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 to 1 L withwater. 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
