ASTM_D_2373_-_05_2011.pdf

Designation:D237305(Reapproved 2011)Standard Test Method forDetermination of Cobalt in Paint Driers by EDTA Method1This standard is issued under the fixed designation D2373;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.Scope1.1 This test method covers a titrimetric determination ofcobalt in liquid paint driers that can be dissolved in glacialacetic acid and utilizes the disodium salt of ethylenediaminetet-raacetic acid dihydrate(EDTA).1.2 This test method is not applicable to drier blends.Ifdriers other than cobalt are present,they may interfere byreacting with EDTA under the conditions used for analysis.1.3 All cations that can be titrated with EDTA in alkalinemedia interfere and must not be present in the sample.1.4 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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 determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D600 Specification for Liquid Paint DriersD1193 Specification for Reagent WaterE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)3E300 Practice for Sampling Industrial Chemicals3.Summary of Test Method3.1 The liquid drier is dissolved in glacial acetic acid,diluted with isopropyl alcohol and water,and treated with anexcess of standard EDTA solution.The excess is titrated withstandard cupric sulfate solution using PAN as the metalindicator.4.Significance and Use4.1 The amount of cobalt drier used in oxidizing-typecoatings significantly affects their drying properties.This testmethod may be used to confirm the stated cobalt content of apure liquid cobalt drier soluble in glacial acetic acid andmanufactured for use by the coatings industry.5.Apparatus5.1 Centrifuge,capable of developing 1000 to 2000 g.6.Reagents6.1 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.4Other 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.6.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Type II of Specification D1193.6.3 Ammonium Chloride(NH4Cl).6.4 Ammonium Hydroxide(sp gr 0.90)Concentrated ammo-nium hydroxide(NH4OH).6.5 Buffer Solution(pH 10.0)Dissolve 67.5 g of NH4Cl inwater,add 570 mL of concentrated NH4OH(sp gr 0.90),anddilute to 1 L.6.6 Cupric Sulfate,Standard Solution(0.05 M)Dissolve12.5 g of cupric sulfate pentahydrate(CuSO45H2O)in waterand dilute to 1 L.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1,2011.Published June 2011.Originallyapproved in 1965.Last previous edition approved in 2005 as D2373 05.DOI:10.1520/D2373-05R11.2For 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.4Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.7 Eriochrome Black-T IndicatorTriturate 0.20 g of theconcentrated dye with 100 g of sodium chloride(NaCl)andstore in a tightly stoppered jar.This mixture remains stable forseveral years.6.8 EDTA,Standard Solution(0.05 M)Dissolve 18.62 gof EDTA in water and dilute to 1 L.Store in a polyethylene orborosilicate glass bottle.6.9 Glacial Acetic Acid(sp gr 1.06).6.10 Isopropyl Alcohol,99.5%.6.11 Methyl Red Indicator SolutionDissolve 0.2 g ofmethyl red in 100 mL of methanol,ethanol,or isopropanol.6.12 PAN Indicator(1(2-Pyridylazo)