1、Designation:D176789(Reapproved 2009)Standard Test Method forEthylene Diamine Tetraacetate(EDTA)in Soaps or SyntheticDetergents1This standard is issued under the fixed designation D1767;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,
2、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.Scope1.1 This test method covers the determination of ethylenediamine tetraacetate(EDTA)in soaps and synthetic detergent
3、s.Throughout this test method EDTA represents the hydrateddisodium salt containing 2 moles of H2O.In the chemicalliterature this is frequently abbreviated to Na2H2Y4 2H2O.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 Th
4、is 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.Material SafetyData Shee
5、ts are available for reagents and materials.Reviewthem for hazards prior to usage.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent Water3.Purity of Reagents3.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thata
6、ll reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lesseni
7、ng theaccuracy of the determination.3.2 Unless otherwise indicated,references to water shall beunderstood to mean reagent water conforming to SpecificationD1193.4.Reagents4.1 Copper Sulfate Solution(1 mL=0.0037 g EDTA diso-dium salt)Dissolve 2.497 g of copper sulfate(CuSO4 5H2O)in water and dilute t
8、o 1 L.The actual EDTA equivalent shouldbe determined by the titration of a known weight of EDTAdisodium salt.4.2 PAN Indicator SolutionDissolve 0.1 g of 1-(2pyridylazo)-2-naphathol4in 100 mL of methyl alcohol.5.Procedure5.1 Weigh to the nearest 0.001 g a 3 to 5-g portion of thesample estimated to co
9、ntain 1%of EDTA disodium salt.Varythe amount of the sample used depending upon the actualamount of EDTA present.Weigh into a 250-mL beaker,diluteto approximately 75 mL with water,and adjust the pH toapproximately 5.0 by the addition of acetic acid(Note 1).Add4 drops of the PAN indicator solution.Tit
10、rate the sample withCuSO4solution to a transition in color from yellow to red.NOTE1Removal of soap fatty acids by filtration through a wet filterpaper prior to titration will sharpen the end point.6.Calculation6.1 Calculate the percentage of EDTA disodium salt in thesample as follows:EDTA,weight%5AB
11、/C!3100(1)where:A=millilitres of CuSO4solution required for titration of thesample,1This test method is under the jurisdiction of ASTM Committee D12 on Soapsand Other Detergents and is the direct responsibility of D12.12 on Analysis andSpecifications of Soaps,Synthetics,Detergents and their Componen
12、ts.Current edition approved Oct.1,2009.Published December 2009.Originallyapproved in 1960.Last previous edition approved in 2003 as D1767 89(2003).DOI:10.1520/D1767-89R09.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual
13、Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar
14、 Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.4Eastman Organic Chemical No.7192 has been found satisfactory for thispurpose.Copyright ASTM International,100 Barr Harbor Drive
15、,PO Box C700,West Conshohocken,PA 19428-2959.United States1 B=grams of EDTA disodium salt equivalent to 1 mL of theCuSO4solution,andC=grams of sample used.7.Precision and Bias7.1 The following criteria should be used for judging theacceptability of results(95%probability):7.1.1 Liquid SoapDuplicate
16、results by the same operatorshould not be considered suspect unless they differ by morethan 60.01%.The overall reproducibility is 60.03%.7.1.2 Synthetic DetergentsDuplicate results by the sameoperator should not be considered suspect unless they differ bymore than 60.01%.The overall reproducibility is 60.02%.8.Keywords8.1 copper sulfate titration;EDTA;ethylene diamine tet-raacetateASTM International takes no position respecting the validity of any patent rights asserted in connection with any it