1、Designation: D 6401 99 (Reapproved 2004)Standard Test Method forDetermining Non-Tannins and Tannin in Extracts ofVegetable Tanning Materials1This standard is issued under the fixed designation D 6401; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、and 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 thestan
4、dard. 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 t
5、he applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2617 Test Method for Total Ash in LeatherD 4901 Practice for Preparation of Solution of Liquid Veg-etable Tannin ExtractsD 4902 Test Method for Evaporation and Drying of Ana-lytical SolutionsD 4903
6、Test Method for Total Solids and Water in VegetableTanning Material ExtractsD 4905 Practice for Preparation of Solution of Solid, Pasty,and Powdered Vegetable Tannin ExtractsD 6402 Test Method for Determining Soluble Solids andInsolubles in Extracts of Vegetable Tanning MaterialsD 6405 Practice for
7、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 dissolved orsuspended in water, are part of the soluble solids deter
8、mined byTest Method D 6402, 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, are part of the soluble solids determined byTest Method D 64
9、02, 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 D 4901 or D 4905) or of the waterextract from raw or spent materials (Practice D 6405) is driedovernight in a force
10、d-air oven (Test Method D 4902) and thesolid residue remaining is determined and defined as the totalsolids for that sample (Test Method D 4903). Another aliquotof the same solution is passed through a specified filteringprocedure and the quantity of solid residue remaining in thefiltrate is determi
11、ned 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 D 6402). Another aliquot of the original analyti-cal solution or water extract is mixed with a prepared hidepowder m
12、aterial 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; the calculated difference between the total solublesolid
13、s and the soluble non-tannins is defined as the tannincontent for that sample.1This test method is under the jurisdiction of ASTM 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 Method A22
14、 of the OfficialMethods of the American Leather Chemists Association.Current edition approved April 1, 2004. Published May 2004. Originallyapproved in 1999. Last previous edition approved in 1999 as D 6401 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custom
15、er 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.B
16、ox 210014, Cincinnati, OH 45221-0014.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 This test method is used to determine the proportion ofthe total soluble solids which are soluble non-tannins and theprop
17、ortion 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 tannin extracts or the water extract solutionsprepared from raw or spent materials.5.3 The
18、 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 absorbed or bound by a prepared hide powdermaterial.5.5 The results of this test method are
19、 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 The uniformity and consistency of the Kaolin pastelayer deposited onto the filter paper;5.5
20、.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 method be followed exactly inorder to obtain reproducible results both among specimenswithin a
21、 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 radius of 6 mm, the bottom shall be flat and notcupped in the center, and the top edge shall b
22、e 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.6.3 Pipet, 100 mL capacity, preferably with a wide orificeapproximately 2.4 mm (332 in.) d
23、iameter 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 creases.6.6 Funnel, 100 to 125 mm top diameter, 60 angle bowl,and 150 mm stem length.6.7 Shake
24、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 well.6.8 Shaking Machine, rotating type, equipped to hold 0.95 L(32 oz) bottles for end-
25、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 be not less than5.1 cm (2 in.) nor more than 7.6 cm (3 in.) from the center ofthe shaft.6.
26、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 48.6.10 Kaolin5, acid-washed kaolin clay which conforms tothe following specifications:6.10.1
27、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 through thestandard filter paper (see 6.5). A 100 mL aliquot of the clearfiltrate should hav
28、e 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 100 mL of solution). The solution shallnot be more than 30 days old when used.6.12 Hide
29、 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 % asdetermined by Test Method D 4902.6.12.3 The ash content shall be less than 0.3 % as deter-mine
30、d by Test Method D 2617.6.12.4 A mixture 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 than 5.4.6.12.5 A sample of the hide powder shall be carried throughthe analytical proc
31、edure 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 of hide powder should be testedagainst the hide powder of the previous shipment usi
32、ng certainstandard extracts. The new hide powder shall give an averagenon-tannin percentage which differs by less than 6 0.2 fromthe comparable non-tannin percentage obtained with the hidepowder from the previous shipment.6.12.7 Hide powder, prepared as described below, shall beused for the analysis
33、 of tanning materials on the same day thatit is prepared.6.13 Balance, analytical balance which will weigh up to 100g with an accuracy of 6 0.1 mg (6 0.0001 g).4The sole source of supply of Stherefore two values for soluble non-tannins will be obtainedfor each extract or tanning material. The averag
34、e (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 sample shall be calculatedas follows:tannin, % 5 solu
35、ble solids %! non2tannins %! (2)where:soluble solids (%) is determined as in Test Method D 6402, 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 by no morethan 0.3.9.2.2 The average (mean) of these
36、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 A22 of TheOfficial Methods of the ALCA. This test meth
37、od has long beenin use and was approved for publication before the inclusion ofprecision and bias statements were mandated. The originalinter-laboratory test data is no longer available. The user iscautioned to verify by the use of reference materials, ifavailable, that the precision and bias (or re
38、producibility) 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 and filter-ing through the specially constructed filt
39、er 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 true non-tannin ortannin content of the sample.12.
40、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 of this standard are expressly advised that determi
41、nation 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 five years andif not revised, either reapproved or wi
42、thdrawn. 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 committee, which you may attend. If you feel that y
43、our 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, 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).D 6401 99 (2004)4
