1、Designation: D6401 99 (Reapproved 2016)Standard Test Method forDetermining Non-Tannins and Tannin in Extracts ofVegetable Tanning Materials1This standard is issued under the fixed designation D6401; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se 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 thequantity of soluble non-tannins and
3、 tannin in solutions oftannin extracts, water extracts of vegetable tanning materials,or tanning liquors. The method is applicable to the analysis ofliquid, solid, pasty, and powdered extracts and to extracts ofraw or spent materials.1.2 The values stated in SI units are to be regarded as thestandar
4、d. The inch-pound units given in parentheses are forinformation only.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
5、applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2617 Test Method for Total Ash in LeatherD3790 Test Method for Volatile Matter (Moisture) ofLeather by Oven DryingD4901 Practice for Preparation of Solution of Liquid Veg-etable Tannin ExtractsD4902 Tes
6、t Method for Evaporation and Drying of Analyti-cal SolutionsD4903 Test Method for Total Solids and Water in VegetableTanning Material ExtractsD4905 Practice for Preparation of Solution of Solid, Pastyand Powdered Vegetable Tannin ExtractsD6402 Test Method for Determining Soluble Solids andInsolubles
7、 in Extracts of Vegetable Tanning MaterialsD6405 Practice for Extraction of Tannins from Raw andSpent Materials2.2 ALCA Method:A22 Non-Tannins and Tannin33. Terminology3.1 Definitions:3.1.1 soluble non-tanninsnon-volatile materials present intannin extracts and raw or spent materials that are dissol
8、ved orsuspended in water, are part of the soluble solids determined byTest Method D6402, and do not react with or bind to hidepowder when mixed as in this test method.3.1.2 tanninsnon-volatile materials present in tannin ex-tracts and raw or spent materials that are dissolved or sus-pended in water,
9、 are part of the soluble solids determined byTest Method D6402, and do react with or bind to hide powderwhen mixed as in this test method.4. Summary of Test Method4.1 An aliquot of the analytical solution prepared fromtannin extracts (Practices D4901 or D4905) or of the waterextract from raw or spen
10、t materials (Practice D6405) is driedovernight in a forced-air oven (Test Method D4902) and thesolid residue remaining is determined and defined as the totalsolids for that sample (Test Method D4903).Another aliquot ofthe same solution is passed through a specified filteringprocedure and the quantit
11、y of solid residue remaining in thefiltrate is determined and defined as the soluble solids for thatsample; the calculated difference between the total solids andthe soluble solids is defined as the insolubles for that sample(Test Method D6402). Another aliquot of the original analyti-cal solution o
12、r water extract is mixed with a prepared hidepowder material, with the resulting solution being passedthrough the same filtering procedure as for the soluble solidsanalysis. The quantity of solid residue remaining in the filtrateis determined and defined as the soluble non-tannins for thatsample; th
13、e calculated difference between the total soluble1This test method is under the jurisdiction ofASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.01 on Vegetable Leather. Thismethod has been adapted from, and is a replacement for, MethodA22 of the OfficialMethods of th
14、e American Leather Chemists Association.Current edition approved Sept. 1, 2016. Published October 2016. Originallyapproved in 1999. Last previous edition approved in 2009 as D6401 99 (2009).DOI: 10.1520/D6401-99R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM
15、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,
16、 P.O.Box 210014, Cincinnati, OH 45221-0014.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1solids and the soluble non-tannins is defined as the tannincontent for that sample.5. Significance and Use5.1 This test method is used to deter
17、mine the proportion ofthe total soluble solids which are soluble non-tannins and theproportion which are tannins in a solution of tannin extract orin the water extract from raw or spent materials prepared fortannin analysis.5.2 The specimens are aliquots from the analytical solutionsprepared from ta
18、nnin extracts or the water extract solutionsprepared from raw or spent materials.5.3 The soluble non-tannins are defined as the portion of thesoluble solids which are not absorbed or bound by a preparedhide powder material.5.4 The tannins are defined as the portion of the solublesolids which are abs
19、orbed or bound by a prepared hide powdermaterial.5.5 The results of this test method are dependent on a greatmany variables, but particularly upon:5.5.1 The temperature conditions under which the solutionswere prepared and stored and the temperature at which thecurrent analysis is performed;5.5.2 Th
20、e uniformity and consistency of the Kaolin pastelayer deposited onto the filter paper;5.5.3 The rate of solution run-out from the pipette;5.5.4 Conditions related to the properties of the hide powderused to react with the tannin content of the solution; etc. It is,therefore, essential that the metho
21、d be followed exactly inorder to obtain reproducible results both among specimenswithin a laboratory and for analyses between laboratories.6. Apparatus and Reagents6.1 Tannin Dish, crystallizing dish, borosilicate glass, 50mm tall, 70 mm outside diameter. The bottom corner shall berounded to a radiu
22、s of 6 mm, the bottom shall be flat and notcupped in the center, and the top edge shall be rounded andpolished.6.2 Watch Glass, a suitable size (approximately 150 mmdiameter) to be used as a cover for the funnel and filter paperand a suitable size (75 mm) to be used as a cover for the tannindishes.6
23、.3 Pipet, 100 mL capacity, preferably with a wide orificeapproximately 2.4 mm (332 in.) diameter and 15-25 s deliverytime.6.4 Volumetric Flasks, graduated to deliver 200 mL boro-silicate flask (Pyrex No. 5840 works well).6.5 Filter Paper4, 21.5 cm diameter, pleated to contain 32evenly divided crease
24、s.6.6 Funnel, 100 to 125 mm top diameter, 60 angle bowl,and 150 mm stem length.6.7 Shake Bottles, 0.95 L (32 oz), with rubber stoppers. Thebottles shall be approximately 21.6 cm (8.5 in.) overall heightand 8.9 cm (3.5 in.) diameter. One-quart canning jars (Mason-type) with plastic screw-on lids work
25、 well.6.8 Shaking Machine, rotating type, equipped to hold 0.95 L(32 oz) bottles for end-over-end agitation of hide powder andanalytical solution. The speed of rotation shall be 60 6 2 rpm,and the machine shall be so constructed that the side of theshake bottle adjacent to the rotating shaft shall b
26、e not less than5.1 cm (2 in.) nor more than 7.6 cm (3 in.) from the center ofthe shaft.6.9 Cloth, The cloth shall be of cotton, with a nominal(unbleached) thread count of 48 by 48 and a weight of 1.65yards per 454 g (1 lb). When bleached, the thread count will beapproximately 52 to 53 by 43 to 48.6.
27、10 Kaolin5, acid-washed kaolin clay which conforms tothe following specifications:6.10.1 Suspend 1.0 g kaolin in 100 mL distilled water. ThepH value should be between 4.5 and 6.0 after 5 min.6.10.2 A mixture of 2.0 g kaolin and 200 mL distilled waterare shaken for 10 min and the mixture filtered thr
28、ough thestandard filter paper (see 6.5). A100 mL aliquot of the clearfiltrate should have less than 0.001 g of residue after evapora-tion and oven-drying in a platinum dish.6.11 Chrome Alum Solution, a 3 % solution, prepared bydissolving CrK(SO4)212 H2O in distilled water at roomtemperature (3 g per
29、 100 mL of solution). The solution shallnot be more than 30 days old when used.6.12 Hide Powder5The hide powder shall meet the fol-lowing specifications:6.12.1 The hide powder shall be finely ground and uniformin texture with no lumps present.6.12.2 The moisture content should be 12 to 15 % asdeterm
30、ined by Test Method D4902.6.12.3 The ash content shall be less than 0.3 % as deter-mined by Test Method D2617.6.12.4 Amixture prepared from 7.0 g of air-dry hide powdersuspended in 100 mL of 0.1 N KCl and set aside for 24 h withoccasional shaking shall have a pH value not less than 5.0 norgreater th
31、an 5.4.6.12.5 Asample of the hide powder shall be carried throughthe analytical procedure for the determination of non-tanninsdescribed below using distilled water in place of the analyticalsolution.The water-soluble content of the resulting filtrate shallnot exceed 0.004 g.6.12.6 Each new shipment
32、of hide powder should be testedagainst the hide powder of the previous shipment using certainstandard extracts. The new hide powder shall give an averagenon-tannin percentage which differs by less than 6 0.2 from4The sole source of supply of Stherefore two values for soluble non-tannins will be obta
33、inedfor each extract or tanning material. The average (mean) ofthese values shall be taken as the percentage of solublenon-tannins in the sample under test.9.1.4 Duplicates are considered to be in good agreementwhen the percent non-tannins differ by no more than 0.2.9.2 The amount of tannin in the s
34、ample shall be calculatedas follows:tannin, % 5 soluble solids %! 2 non-tannins %! (2)where:soluble solids (%) is determined as in Test Method D6402, andnon-tannins (%) is determined as in 9.1.9.2.1 Duplicates are considered to be in good agreementwhen the duplicate values for tannin content differ
35、by no morethan 0.3.9.2.2 The average (mean) of these duplicate values fortannin content shall be taken as the percentage of tannin in thesample under test.10. Report10.1 Record the non-tannin and tannin results to the nearest0.01 %.11. Precision and Bias11.1 This test method is adopted from Method A
36、22 of TheOfficial Methods of theALCA. This test method has long beenin use and was approved for publication before the inclusion ofprecision and bias statements was mandated. The originalinter-laboratory test data are no longer available. The user iscautioned to verify by the use of reference materi
37、als, ifavailable, that the precision and bias (or reproducibility) of thistest method is adequate for the contemplated use.11.2 The non-tannin content obtained by this test method isoperationally defined as that portion of the soluble solids of thespecimen collected after reacting with hide powder a
38、nd filter-ing through the specially constructed filter system. The tannincontent is defined as the difference between the soluble solidsand the non-tannins of the specimen. There is no independentmeasure of the true non-tannin or tannin content of a sample.Therefore the bias cannot be related to the
39、 true non-tannin ortannin content of the sample.12. Keywords12.1 non-tannins; soluble non-tannins; tannins; tanninanalysis; vegetable tannin analysisASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users
40、 of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every f
41、ive years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical
42、 committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
43、PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 99 (2016)4
