1、Designation:D112399(Reapproved 2015)Standard Test Methods forWater in Engine Coolant Concentrate by the Karl FischerReagent Method1This standard is issued under the fixed designation D1123;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revis
2、ion,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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 These test methods cov
3、er the determination of the waterpresent in new or unused glycol-based coolant concentratesusing a manual(Test Method A)or an automatic(Test MethodB)coulometric titrator procedure.1.2 Many carbonyl compounds react slowly with the Fis-cher reagent,causing a fading end point and leading to highresults
4、.A modified Fischer reagent procedure is included thatminimizes these undesirable and interfering reactions.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety proble
5、ms,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 hazardsstatements see Sections 8 and 16.2.Referenced Documents2.1 ASTM Sta
6、ndards:2D156 Test Method for Saybolt Color of Petroleum Products(Saybolt Chromometer Method)D1176 Practice for Sampling and Preparing Aqueous Solu-tions of Engine Coolants orAntirusts for Testing PurposesD1193 Specification for Reagent WaterE203 Test Method for Water Using Volumetric Karl FischerTit
7、ration3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 color end pointthat point during the titration whenthe color change from yellow to orange-red is sharp and easilyrepeated.The orange-red color must persist for at least 30 s inorder to indicate an end point.3.1.1.1 Discussio
8、nView the color by transmitted daylightor by transmitted light from an artificial daylight lamp,such asone that complies with the specification given in Test MethodD156.3.1.2 instrument end pointfor the purpose of these tests,that point in the titration when two small platinum electrodes,upon which
9、a potential of 20 to 50 mV has been impressed,aredepolarized by the addition of 0.05 mL of Fischer reagent(6mg of water/mL),causing a change of current flow of 10 to 20A that persists for at least 30 s.3.1.2.1 DiscussionThis end point is sometimes incorrectlycalled the“dead stop,”which is the revers
10、e of the above.4.Summary of Test Method4.1 These test methods are based essentially on the reduc-tion of iodine by sulfur dioxide in the presence of water.Thisreaction can be used quantitatively only when pyridine and analcohol are present to react as follows:I21SO21H2OSO312HI(1)4.2 In order to dete
11、rmine water,Karl Fischer reagent isadded to a solution of the sample in anhydrous high-puritymethanol until all water present has been consumed.This isevidenced by the persistence of the orange-red end point color,or alternatively by an indication on a galvanometer or similarcurrent-indicating devic
12、e that records the depolarization of apair of noble metal electrodes.The reagent is standardized bythe titration of water.NOTE1It is believed that these methods give all the informationrequired for determining the water in coolant formulations.Shouldadditional information on water determinations be
13、needed,referenceshould be made to Test Method E203.5.Significance and Use5.1 The total apparent water in engine coolant concentrateas determined by Karl Fischer titrations consists of the follow-ing:(1)water present in the original glycol base;(2)wateradded(for example,inhibitor solutions);(3)water
14、of hydration1These test methods are under the jurisdiction of ASTM Committee D15 onEngine Coolants and Related Fluids and are the direct responsibility of Subcom-mittee D15.04 on Chemical Properties.Current edition approved May 1,2015.Published June 2015.Originallyapproved in 1950.Last previous edit
15、ion approved in 2009 as D1123 99(2009).DOI:10.1520/D1123-99R15.2For 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.Cop
16、yright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 of inhibitors(for example,Na2B4O75H2O);(4)water formedin the chemical reaction between borate and ethylene glycol,producing boratediol condensate and water;and(5)quantita-tive interference by the reaction of the reagent with inhibitorssuch as tetraborate or sodium hydroxide.TEST METHOD AMANUAL TITRATION6.Apparatus6.1 Titration VesselFor color end point titrations,use a100 or 250-mL volumetr