ASTM_D_6407_-_99_2014.pdf

Designation:D640799(Reapproved 2014)Standard Test Method forAnalysis of Iron and Copper in Vegetable Tanning Materials1This standard is issued under the fixed designation D6407;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 is intended for use in determining ironand copper content in vegetable tanning materials.This testmethod is applicable to liquid,solid,pasty and powderedextracts,to raw and spent materials,and to tannery liquors.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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:2D4901 Practice for Preparation of Solution of Liquid Veg-etable Tannin ExtractsD4902 Test Method for Evaporation and Drying of Analyti-cal SolutionsD6404 Practice for Sampling Vegetable Materials Contain-ing TanninD6405 Practice for Extraction of Tannins from Raw andSpent Materials2.2 ALCA Methods:A31 Method for Copper and Iron in Tanning Materials33.Summary of Test Method3.1 A specified quantity of the tanning material is analyzedfor iron and copper and content.4.Significance and Use4.1 This test method is used to determine the quantity ofiron and copper present in vegetable tanning materials orvegetable tannin extracts prepared using Practices D4901,D6404,or D6405.4.2 Because of the possibility of errors in this test method itis essential that the method be followed exactly in order toobtain reproducible results both among specimens within alaboratory and for analyses between laboratories.5.Apparatus and Reagents5.1 Sulfuric Acid,concentrated(96%).5.2 Sulfuric Acid Solution,diluted 1:20 with distilled water.5.3 Nitric Acid,fuming.5.4 Hydrochloric Acid,concentrated(36%).5.5 Hydrochloric Acid Solution,0.1 N.5.6 Bromine Water,saturated solution.5.7 Ammonium Hydroxide Solution,concentrated diluted1:1 with distilled water.5.8 Potassium Permanganate Solution,0.1 N.5.9 Potassium(or Ammonium)Thiocyanate Solution,10 gshall be dissolved in distilled water and diluted to 100 mL withdistilled water.5.10 Stock Iron Solution,This may be a purchased ironstandard solution or may be prepared as follows:5.10.1 0.70 g of crystallized ferrous ammonium sulfateFeSO4(NH4)2SO46H2O shall be dissolved in 50 mL ofdistilled water and 20 mL of dilute sulfuric acid(diluted 1:4).5.10.2 This solution shall be titrated with 0.1 N potassiumpermanganate solution until a faint pink persists for 1 minuteand the iron is completely oxidized.5.10.3 Dilute this solution to 1 L with distilled water.1 mLof this solution is equivalent to 0.0001 g Fe.This solution shallbe stored in brown bottles and be protected from light.5.10.4 Standard Iron Solution,10 mL of the prepared stocksolution,or its equivalent of purchased iron standard solution,shall be diluted to 100 mL with distilled water.1 mL of thisstandard solution is equivalent to 0.00001 g Fe.The standardsolution shall be freshly prepared for each analysis.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.01 on Vegetable Leather.Thistest method has been adapted from and is a replacement for Method A31 of theOfficial Methods of the American Leather Chemists Association.Current edition approved Nov.1,2014.Published December 2014.Originallyapproved in 1999.Last previous edition approved in 2009 as D6407 99(2009).DOI:10.1520/D6407-99R14.2For 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.3Official Methods of the American Leather Chemists Association.Availablefrom the American Leather Chemists Association,University of Cincinnati,P.O.Box 210014,Cincinnati,OH 45221-0014.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.11 Stock Copper Solution,3.9283 g of copper sulfatecrystals(CuSO45H2O)shall be dissolved in distilled waterand diluted to 1 L with distilled water.1 mL of this solution isequivalent to 0.001 g Cu.5.11.1 Standard Copper Solution,10 mLof the stock coppersolution shall be diluted to 1 L with distilled water and the pHadjusted to between 5.5 and 6.0.1 mL of this standard solutionis equivalent to 0.00001 g Cu.The standard solution shall befreshly prepared for each analysis.5.12 Xanthate Solution,1.0 g of potassium ethyl xanthateshall be dis