ASTM_E_1064_-_12.pdf

Designation:E106412Standard Test Method forWater in Organic Liquids by Coulometric Karl FischerTitration1This standard is issued under the fixed designation E1064;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 determination of water from0 to 2.0%mass in most liquid organic chemicals,with KarlFischer reagent,using an automated coulometric titrationprocedure.Use of this test method is not applicable forliquefied gas products such as Liquid Petroleum Gas(LPG),Butane,Propane,Liquid Natural Gas(LNG),etc.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 Review the current material safety data sheets(MSDS)fordetailedinformationconcerningtoxicity,first-aidprocedures,handling,and safety precautions.1.4 This standard does not purport to address all of thesafety problems,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.Specific precau-tionary statements are given in Section 8.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4672 Test Method for Polyurethane Raw Materials:Deter-mination of Water Content of PolyolsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)3E203 Test Method for Water Using Volumetric Karl FischerTitration3.Summary of Test Method3.1 This test method is based on the Karl Fischer reactionfor determining waterthe reduction of iodine by sulfurdioxide in the presence of water to form sulfur trioxide andhydriodic acid.The reaction becomes quantitative only whenpyridine or other organic base and methanol or other alcoholare present.Unlike the volumetric Karl Fischer reagents thatinclude iodine,the coulometric technique electrolytically gen-erates iodine,with 10.71 C of generating current correspondingto 1 mg of water in accordance with Faradays law.4.Significance and Use4.1 The coulometric technique is especially suited for de-termining low concentrations of water in organic liquids thatwould yield small titers by the Karl Fischer volumetricprocedure.The precision and accuracy of the coulometrictechnique decreases for concentrations of water much greaterthan 2.0%because of the difficulty in measuring the small sizeof sample required.The test method assumes 100%efficiencyof coulombs in iodine production.Provision is made forverifying this efficiency.(See Table 1 and Note 6.)5.Interferences5.1 Interfering substances are the same as are encounteredin the volumetric Karl Fischer titration.A detailed discussionof interfering substances can be found in the treatise on“Aquametry.”45.2 Test Method E203 discusses organic compounds inwhich water may be determined directly and compounds inwhich water cannot be determined directly,but in whichinterferences may be eliminated by suitable chemical reactions.6.Apparatus6.1 Automatic Titrator,5consisting of a control unit,titrationvessel,dual platinum sensing electrode,generator assembly,1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicalsand is the direct responsibility of SubcommitteeE15.01 on General Standards.Current edition approved April 1,2012.Published May 2012.Originallyapproved in 1985.Last previous edition approved in 2008 as E1064 08.DOI:10.1520/E1064-12.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4J.Mitchell,Jr.and D.M.Smith,“Aquametry”A Treatise on Methods for theDetermination of Water,Part IIIThe Karl Fischer Reagent,2nd Ed.,J.Wiley andSons,Inc.,New York,NY 1990.5Basic references to the automatic coulometric titrator:M.T.Kelley,R.W.Stelzner,W.R.Laing,and D.J.Fisher,Analytical Chemistry 31,No.2,220(1959)and A.W.Meyer,Jr.and C.M.Boyd,Analytical Chemistry 31,No.2,215(1959).*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 and magnetic stirrer.The instrument is designed to coulometri-cally generate iodine that reacts stoichiometrically with thewater present in the sample solution.The coulombs of elec-tricity required to generate the reagent are converted tomicrograms of water,which is obtained as a direct digitalreadout.6.2 Syringe,50-mL,fitted with an 115-mm hypodermicneedle for removing