1、Designation:D490599(Reapproved 2009)Standard Practice forPreparation of Solution of Solid,Pasty and PowderedVegetable Tannin Extracts1This standard is issued under the fixed designation D4905;the number immediately following the designation indicates the year oforiginal adoption or,in the case of re
2、vision,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 practice covers a standard procedure for use inpreparing the analytical solution required for the a
3、nalysis ofsolid,pasty,or powdered vegetable tannin extracts.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 therespo
4、nsibility 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:2D4903 Test Method for Total Solids and Water in VegetableTanning Material ExtractsD4904 Pract
5、ice for Cooling of Analytical SolutionsD6403 Test Method for Determining Moisture in Raw andSpent MaterialsD6404 Practice for Sampling Vegetable Materials Contain-ing Tannin2.2 ALCA Method:A11 Preparation of Solution of Solid,Pasty,and PowderedExtracts33.Summary of Practice3.1 This practice describe
6、s a procedure to follow in thepreparation of analytical strength solutions from samples ofsolid,pasty,and powdered vegetable tannin extracts.4.Significance and Use4.1 The concentration of tannins in solid,pasty,and pow-dered extracts needs to be reduced to analytical strength fortannin analyses.4.2
7、Vegetable tannin extracts are heterogeneous mixtures ofcomponents with varying solubility.4.3 The solubility of such extracts is influenced by tempera-ture and concentration,which affect the degree of dispersionand size of the component particles.4.4 Since extracts have greater solubility in hot wat
8、er thancold,it is desirable to dissolve and disperse an extract in hotwater and then let the solution cool slowly to standard roomtemperature.4.5 It is often difficult to reduce samples of solid andparticularly pasty extracts to specimen size and at the sametime ensure representative sampling.Theref
9、ore,caution isadvised in drawing conclusions on the precision and bias of theresults obtained on such extracts;where difficulties in samplepreparation are experienced,little confidence can be placed inthe results.5.Specimen5.1 The specimen shall consist of a portion of the extractsample,prepared as
10、described in Practice D6404,sufficient togive a solution containing as nearly as possible 4 g of tanninper L(not less than 3.75 g,nor more than 4.25 g,per L).6.Apparatus and Reagents6.1 Formaldehyde40%solution.6.2 TolueneAssay$99.5%.6.3 Small Mortar and Pestle.6.4 1-L Volumetric Flask,M.C.A.type,mix
11、ing bulb style.7.Procedure7.1 Empty the sample onto a sheet of clean,glazed paper(orsuitable clean,smooth foil material),roughly crush any largelumps,and quickly mix and quarter the whole.From eachquarter,take a small representative portion,quickly crush,transfer to a small,glass stoppered weighing
12、bottle,and take tothe balance.Without delay,transfer the analytical specimen to1This practice is under the jurisdiction ofASTM Committee D31 on Leather andis the direct responsibility of Subcommittee D31.01 on Vegetable Leather.Thispractice has been adapted from and is a replacement for Method A11 o
13、f the OfficialMethods of the American Leather Chemists Association.Current edition approved April 1,2009.Published July 2009.Originallyapproved in 1989.Last previous edition approved in 2004 as D4905 99(2004).DOI:10.1520/D4905-99R09.2For referenced ASTM standards,visit the ASTM website,www.astm.org,
14、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
15、Cincinnati,P.O.Box 210014,Cincinnati,OH 452210014.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 a tared container of suitable size and weigh to the nearest 0.1mg.Each sample shall be handled individually,and all opera-tions carried out
16、as quickly as possible,up to this point,and allother precautions taken to minimize changes in moisturecontent.7.2 Pasty ExtractsWhere the extract has a moisture con-tent such that it cannot be ground,weigh the sample,broken orcut,into small pieces(W1)and bring to approximate equilib-rium with the laboratory atmosphere by drying for severalhours at a temperature not exceeding 60C.Allow the sampleto remain exposed to the air in the laboratory until theapproximate equilibrium has been attained.Weig
