ASTM_D_3113_-_92_1998.pdf

Designation:D 3113 92(Reapproved 1998)An American National StandardStandard Test Methods forSodium Salts of EDTA in Water1This standard is issued under the fixed designation D 3113;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover the determination of eithertotal or unchelated sodium salts of ethylenediaminetetraaceticacid(Na4EDTA)in water,particularly water intended for use insteam boilers.Two test methods are given as follows:SectionsTest Method ATotal(Chelated and Unchelated)Sodium Salt ofEDTA7 to 15Test Method BUnchelated Sodium Salt of EDTA16 to 231.2 Test Method A is capable of determining total(chelatedand unchelated)chelating agent even though it may be in theform of heavy metal or alkaline earth chelates.1.3 It is the users responsibility to ensure the validity ofthese test methods for waters of untested matrices.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 use.A specific hazardstatement is given in Note 4.2.Referenced Documents2.1 ASTM Standards:D 888 Test Methods for Dissolved Oxygen in Water2D 1066 Practice for Sampling Steam2D 1129 Terminology Relating to Water2D 1193 Specification for Reagent Water2D 2777 Practice for Determination of Precision and Bias ofApplicable Methods of Committee D-19 on Water2D 3370 Practices for Sampling Water2D 3856 Guide for Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of Water2D 4210 Practice for Intralaboratory Quality Control Proce-dures and a Discussion on Reporting Low-Level Data2E 60 Practice for Photometric and SpectrophotometricMethods for Chemical Analysis of Metals3E 275 Practice for Describing and Measuring Performanceof Ultraviolet,Visible,and Near Infrared Spectrophotom-eters43.Terminology3.1 DefinitionsFor definitions of terms used in these testmethods,refer to Terminology D 1129.4.Significance and Use4.1 EDTA is used in steam boilers to prevent precipitationof calcium,magnesium,and other metal salts,and under someconditions,to remove deposits caused by these elements.4.2 These test methods are used to monitor the presence ofEDTA so that optimum concentration can be maintained.5.Purity of Reagents5.1 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 on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean Type II,reagent waterconforming to Specification D 1193.6.Sampling6.1 Collect the samples in accordance with Practice D 1066or Practices D 3370 as applicable.TEST METHOD ATOTAL SODIUM SALT OF EDTA7.Scope7.1 This test method as described may be applied to waterscontaining free Na4EDTA or heavy metal or alkaline earthchelates of Na4EDTA either individually or in combination,inconcentrations from 0.5 to 20 mg/L.Higher concentrationsmay be determined by dilution.1These test methods are under the jurisdiction of ASTM Committee D-19 onWater and are the direct responsibility of Subcommittee D19.06 on Methods forAnalysis for Organic Substances in Water.Current edition approved Nov.15,1992.Published January 1993.Originallypublished as D3113 72 T.Last previous edition D3113 91.2Annual Book of ASTM Standards,Vol 11.01.3Annual Book of ASTM Standards,Vol 03.05.4Annual Book of ASTM Standards,Vol 03.06.5“Reagent Chemicals,American Chemical Society Specifications,”Am.Chemi-cal Soc.,Washington,DC.For suggestions on the testing of reagents not listed bythe American Chemical Society,see“Analar Standards for Laboratory Chemicals,”BDH Ltd.,Poole,Dorset,U.K.,and the“United States Pharmacopeia.”1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.7.2 It is the users responsibility to ensure the validity of thistest method for waters of untested matrices.8.Summary of Test Method8.1 The intensity of the red-colored zirconium-xylenol or-ange complex formed in a strong acid medium is reduced in thepresence of free EDTA or its metallic complexes throughformation of a more stable zirconium-EDTA complex.Thereduction in color intensity is a measure of total EDTA in thesample reported as milligrams per litre of Na4EDTA.9.Interferences9.1 Nitrilotriacetate(NTA)produ