1、Designation:D136402(Reapproved 2012)Standard Test Method forWater in Volatile Solvents(Karl Fischer Reagent TitrationMethod)1This standard is issued under the fixed designation D1364;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,th
2、e 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.Scope*1.1 This test method covers the
3、 determination of water involatile solvents and chemical intermediates used in paint,varnish,lacquer,and related products.1.2 This test method is not applicable in the presence ofmercaptans,peroxides,or appreciable quantities of aldehydesor amines.1.3 For purposes of determining conformance of an ob
4、-served or a calculated value using this test method to relevantspecifications,test result(s)shall be rounded off“to the nearestunit”in the last right-hand digit used in expressing thespecification limit,in accordance with the rounding-off methodof Practice E29.1.4 The values stated in SI units are
5、to be regarded asstandard.No other units of measurement are included in thisstandard.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 d
6、etermine the applica-bility of regulatory limitations prior to use.1.6 For hazard information and guidance,see the suppliersMaterial Safety Data sheet.2.Referenced Documents2.1 ASTM Standards:2D1500 Test Method for ASTM Color of Petroleum Products(ASTM Color Scale)E29 Practice for Using Significant
7、Digits in Test Data toDetermine Conformance with Specifications3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 instrumental end point,nthat point in the titrationwhen two small platinum electrodes,upon which a potential of20 to 50 mV has been impressed,are depolarized by theadd
8、ition of 0.05 mL of Karl Fischer reagent(6 mg of H2O permL),causing a change of current flow of 10 to 20 A thatpersists for at least 30 s.NOTE1This end point is sometimes incorrectly called the“dead stop”which is the reverse of the above.3.1.2 color end point,nDuring the titration,the solutionfirst
9、turns yellow,then later deepens towards the end of thetitration;the end point is indicated by the change from yellowto orange-red which is quite sharp and easily repeated.Theorange-red color must persist for at least 30 s in order toindicate an end point.NOTE2View the color by transmitted daylight o
10、r by transmitted lightfrom an artificial daylight lamp,such as the one that complies with thespecifications given in Test Method D1500.4.Summary of Test Method4.1 This test method is based essentially upon the reductionof iodine by sulfur dioxide in the presence of water.Thisreaction can be used qua
11、ntitatively only when pyridine and analcohol are present to react with the sulfur trioxide andhydriodic acid produced according to the following reactions:H2O1I21SO213C5H5N2C5H5NHI1C5H5NSO3(1)C5H5NSO31ROHC5H5NHSO4R4.2 To determine water,Karl Fischer reagent(a solution ofiodine,pyridine,and sulfur di
12、oxide,in the molar ratio of1+10+3)dissolved in anhydrous 2-methoxyethanol is addedto a solution of the sample in anhydrous pyridine-ethyleneglycol(1+4)until all water present has been consumed.Thisis evidenced by the persistence of the orange-red end-pointcolor;or alternatively by an indication on a
13、 galvanometer orsimilar current-indicating device which records the depolariza-tion of a pair of noble-metal electrodes.The reagent isstandardized by titration of water.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is th
14、e direct responsibility ofSubcommittee D01.35 on Solvents,Plasticizers,and Chemical Intermediates.Current edition approved July 1,2012.Published September 2012.Originallyapproved in 1955.Last previous edition approved in 2007 as D1364 02(2007).DOI:10.1520/D1364-02R12.2For referenced ASTM standards,v
15、isit 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100
16、Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Significance and Use5.1 Volatile solvents are used in a variety of chemicalprocesses which may be affected by water.Therefore,this testmethod provides a test procedure for assessing compliancewith a specification.6.Apparatus6.1 Titration VesselFor color end point titrations,use a100 or 250-mL volumetric flask,which need not be calibrated;a 250-mL flask fitted with interchangeable electrodes(Fig.1)3may also be used for
