ASTM_D_2791_-_13.pdf

Designation:D279113Standard Test Method forOn-line Determination of Sodium in Water1This standard is issued under the fixed designation D2791;the number immediately following the designation indicates the year oforiginal adoption or,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.Scope*1.1 This test method covers the on-line determination oftrace amounts of sodium in water using an ion-selectiveelectrode.1.2 This test method is based on on-line application of thesodium ion electrode as reported in the technical literature(1-3).2It is generally applicable over the range of 0.01 to10 000 g/L.1.3 The analyst should be aware that adequate collaborativedata for precision and bias statements as required by PracticeD2777 are not provided.See Section 16 for details.1.4 The values stated in SI units are to be regarded asstandard.The inch-pound units given in parentheses are forinformation only.1.5 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 use.For specific hazardstatements see Section 6.2.Referenced Documents2.1 ASTM Standards:3D1066 Practice for Sampling SteamD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1293 Test Methods for pH of WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3864 Guide for On-Line Monitoring Systems for WaterAnalysisD3370 Practices for Sampling Water from Closed ConduitsD5540 Practice for Flow Control and Temperature Controlfor On-Line Water Sampling and Analysis3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1129.4.Significance and Use4.1 Sodium is a pervasive contaminant and it is the firstcation to break through deionization equipment.This testmethod allows measurement of micrograms per litre(parts perbillion)concentrations of sodium in water to monitor low-sodium water sources for indications of contamination orproper operation.Applications include monitoring makeupsystems,condensers,condensatepolishers,feedwater,boilerwater,and steam.4.2 This test method is more sensitive and selective thanconductivity measurements on high purity samples.5.Reagents and Materials5.1 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 onAnalytical Reagents of theAmerican Chemical Society.4In many instances,reagent grade chemicals contain higherlevels of sodium contamination than are compatible with thistest method.It must be ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of Water Unless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Specification D1193,Type I.In addition,the sodium orpotassium content shall not exceed 10 g/L(10 ppb)or 1%ofthe lowest concentration to be determined,whichever is lower.5.2.1 Single-distilled water passed through a mixed beddeionizing unit composed of strong cation and anion resins can1This test method is under the jurisdiction of ASTM Committee D19 on Waterand 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 Surveillance of Water.Current edition approved Jan.1,2013.Published February 2013.Originallyapproved in 1969.Last previous edition approved in 2007 as D2791 07.DOI:10.1520/D2791-13.2The boldface numbers in parentheses refer to the list of references at the end ofthis test method.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 Summary page onthe ASTM website.4Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmaceutical Convention,Inc.(USPC),Rockville,MD.*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 States1 produce an effluent containing less than 1.0 g/L(1.0 ppb)ofsodium.If such water is stored in a closed alkali metal-freecontainer,suchasonemadeofpolyethylene,TFE-fluorocarbon,or stainless steel,subsequent increases inconductivity,us