1、Designation: D 6402 99 (Reapproved 2004)Standard Test Method forDetermining Soluble Solids and Insolubles in Extracts ofVegetable Tanning Materials1This standard is issued under the fixed designation D 6402; the number immediately following the designation indicates the year oforiginal adoption or,
2、in the 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 solid
3、s and insolubles in solutions of tanninextracts, water extracts of vegetable tanning materials, ortanning liquors. This test method is applicable to the analysisof liquid, solid, pasty, and powdered tannin extracts and to thewater extracts of raw or spent materials.1.2 The values stated in SI units
4、are to be regarded as thestandard.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 limita
5、tions prior to use.2. Referenced Documents2.1 ASTM Standards:2D 4901 Practice for Preparation of Solution of Liquid Veg-etable Tannin ExtractsD 4902 Test Method for Evaporation and Drying of Ana-lytical SolutionsD 4903 Test Method for Total Solids and Water in VegetableTanning Material ExtractsD 490
6、5 Practice for Preparation of Solution of Solid, Pasty,and Powdered Vegetable Tannin ExtractsD 6403 Test Method for Determining Moisture in Raw andSpent MaterialsD 6405 Practice for Extraction of Tannins from Raw andSpent Materials2.2 ALCA Methods:A21 Soluble Solids and Insolubles33. Terminology3.1
7、Definitions:3.1.1 insolublesnon-volatile materials present in tanninextracts and raw or spent materials that are dissolved orsuspended in water and do not pass through a filtering processdescribed in this method.3.1.2 soluble solidsnon-volatile materials present in tan-nin extracts and raw or spent
8、materials that are dissolved orsuspended in water and pass through a filtering processdescribed in this method.4. Summary of Test Method4.1 An aliquot of the analytical solution prepared fromtannin extracts (Practices D 4901 or D 4905) or the waterextract from raw or spent materials (Practice D 6405
9、) is driedovernight in a forced-air oven (Test Method D 4902) and thequantity of solid residue remaining is determined and used tocalculate the total solids for that sample (Test Method D 4903).Another aliquot of the same solution is passed through aspecified filtering procedure and the quantity of
10、solid residueremaining in the filtrate is determined and used to calculate thesoluble solids for that sample. The difference between the totalsolids and the soluble solids is defined as the insolubles for thatsample.5. Significance and Use5.1 This test method is used to determine the proportion ofth
11、e total solids which are soluble solids and that proportionwhich are insoluble solids in a solution of tannin extract or inthe 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
12、extract solutionsprepared from raw or spent materials.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 A21 of theOfficial Met
13、hods 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 6402 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servi
14、ceastm.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, Cincinna
15、ti, OH 45221-0014.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 The soluble solids are defined as the portion of the totalsolids which are dissolved in the water and pass through a filterprepared by depositing a layer of Kaolin
16、 paste onto a standardfilter paper.5.4 The insolubles are defined as the portion of the totalsolids which do not pass through the standard filter paperprepared with the layer of Kaolin paste.5.5 The results of this test method are dependent on a greatmany variables but particularly upon:5.5.1 The te
17、mperature 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;5.5.3 The rate of solution run-out from the pipette; etc. It is,therefore
18、, essential that the method 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
19、shall berounded to a radius 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 co
20、ver for the tannindishes.6.3 Pipet, 100 mL capacity, preferably with a wide orificeapproximately 2.4 mm (332 in.) diameter and 15-25 seconddelivery time.6.4 Graduated Cylinder, standard laboratory grade with atleast 225 mL capacity.6.5 Glass Rods, soft glass stirring rods with rounded,fire-polished
21、ends.6.6 Filter Paper4, 21.5 cm diameter, pleated to contain 32evenly divided creases.6.7 Funnel, 100-125 mm top diameter, 60 angle bowl, and150 mm stem length.6.8 Kaolin5, acid-washed kaolin clay which conforms to thefollowing specifications:6.8.1 Suspend 1.0 g kaolin in 100 mL distilled water. The
22、pH value should be between 4.5 and 6.0 after 5 min.6.8.2 A mixture of 2.0 g kaolin and 200 mL distilled wateris shaken for 10 min and the mixture filtered through thestandard filter paper. A 100 mL aliquot of the clear filtrateshould have less than 0.001 g of residue after evaporation andoven-drying
23、 in a platinum dish.6.9 Balance, analytical balance which will weigh up to 100g with an accuracy of 6 0.1 mg (6 0.0001 g).6.10 Drying Oven, a forced-air convection oven (ormechanical-convection draft oven) capable of maintaining atemperature of 100 6 2.0C.6.11 Thermometer, accurate to 6 0.2C used to
24、 check andmonitor the oven set point.6.12 Dessicator, any convenient form or size, using anynormal dessicant.7. Test Specimen7.1 The specimen shall consist of 100 mL of the solutionprepared as described in Practices D 4905, D 4901, or D 6405and after passing through the filtering process described i
25、n thistest method.8. Procedure8.1 Place a pleated filter paper in a 100 to 125 mm funnel.8.1.1 Fold the filter paper to contain 32 evenly dividedpleats.8.2 Add to 2.0 g of kaolin in a clean glass container (a 250mL beaker works well) 25 mL of the well-mixed analyticalsolution (which has been prepare
26、d as described in PracticesD 4901, D 4905, or D 6405) and stir the mixture with a glassstirring rod to form a smooth paste. Then add an additional 200mL of the well-mixed analytical solution (making 225 mLtotal) and again stir the mixture to a uniform suspension.Immediately pour the suspension onto
27、the pleated filter paperin the funnel and collect the filtrate in the container in whichthe solution and kaolin were mixed. After approximately 40mL of the filtrate has been collected, swirl it, to pick up kaolinremaining on the sides and bottom of the container, and returnto the funnel. During this
28、 and subsequent operations, keepfunnels and containers covered with watch glasses to avoidchanges due to evaporation, and maintain the temperature ofthe solution and of the filtrates between 23 and 25C. Repeatthe operation of collecting and repouring 40 mL of filtrate asmany times as is necessary un
29、til the solution has been incontact with the filter paper for exactly 1 h. At the end of thehour, siphon the solution out of the filter as completely aspossible, taking care not to disturb the kaolin film on the filterpaper. Discard this liquid.8.3 Immediately, refill the kaolin-lined paper in the f
30、unnelwith 225 mL of the well-mixed analytical solution which hasbeen kept at a temperature of 23 to 25C. Disturb the kaolinfilm as little as possible during this operation and best resultsare obtained by carefully pouring the solution into the center ofthe cone along a glass stirring rod contacting
31、the edge of thebeaker spout as the liquid is carefully transferred. Pour noadditional solution to this 225 mL onto the filter paper. When40 mL of the filtrate have passed through, collect the nextportion in a clean, dry, glass container and, when about 125 mLhave been collected, remove the container
32、 from beneath thefunnel.8.4 Check this 125 mL for clarity by swirling and viewingagainst the light.8.4.1 If not clear it shall be rejected, and the determinationre-run using a new filter.4The sole source of supply of Stherefore two values for soluble solids will be obtained for eachextract or tannin
33、g material. The average (mean) of these valuesshall be taken as the percentage of soluble solids in the sampleunder test.9.2.1 Duplicates are considered to be in good agreementwhen the percent soluble solids differ by no more than 0.2.9.3 The amount of insolubles in the sample shall be calcu-lated a
34、s follows:insolubles, % 5 total solids %!2soluble solids %! (2)where:total solids (%) is determined as in Test Method D 4903, andsoluble solids (%) is determined as in 9.1.10. Report10.1 Record the soluble solids and insolubles results to thenearest 0.01 %.11. Precision and Bias11.1 This test method
35、 is adopted from Method A21 of TheOfficial Methods of the ALCA. This test method 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 t
36、he use of reference materials, ifavailable, that the precision and bias (or reproducibility) of thistest method is adequate for the contemplated use.11.2 The soluble solids content obtained by this test methodis operationally defined as the dried solids weight of thespecimen collected after filterin
37、g through the specially con-structed filter system. The insolubles content is defined as thedifference between the total solids (Test Method D 4903) andthe soluble solids of the sample. There is no independentmeasure of the true soluble solids content or insolubles contentof a sample. Therefore the
38、bias cannot be related to the truesoluble solids or insolubles content of the sample.12. Keywords12.1 insolubles; soluble solids; tannin analysis; vegetabletannin analysisASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedi
39、n this standard. Users 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 mu
40、st be reviewed every five 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 th
41、eresponsible technical 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 C70
42、0, 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 6402 99 (2004)3
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