1、Designation: D6402 99 (Reapproved 2014)Standard Test Method forDetermining Soluble Solids and Insolubles in Extracts ofVegetable Tanning Materials1This standard is issued under the fixed designation D6402; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 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 thequantity of soluble solids a
3、nd 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 are
4、 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
5、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 SolutionsD4903 Test Method for Total Solids an
6、d Water in VegetableTanning Material ExtractsD4905 Practice for Preparation of Solution of Solid, Pastyand Powdered Vegetable Tannin ExtractsD6403 Test Method for Determining Moisture in Raw andSpent MaterialsD6405 Practice for Extraction of Tannins from Raw andSpent Materials2.2 ALCA Methods:A21 So
7、luble Solids and Insolubles33. Terminology3.1 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
8、 present in tan-nin extracts and raw or spent 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 D4901 or D4905) or the water extract
9、from raw or spent materials (Practice D6405) is dried overnightin a forced-air oven (Test Method D4902) and the quantity ofsolid residue remaining is determined and used to calculate thetotal solids for that sample (Test Method D4903). Anotheraliquot of the same solution is passed through a specifie
10、dfiltering procedure and the quantity of solid residue remainingin the filtrate is determined and used to calculate the solublesolids for that sample. The difference between the total solidsand the soluble solids is defined as the insolubles for thatsample.5. Significance and Use5.1 This test method
11、 is used to determine the proportion ofthe 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 solutionspr
12、epared from tannin extracts or the water 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 repl
13、acement for Method A21 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 2004 as D6402 99 (2009).DOI: 10.1520/D6402-99R14.2For referenced ASTM standards, vi
14、sit 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 Leat
15、her 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 States15.3 The soluble solids are defined as the portion of the totalsolids which are dissolved in
16、the water and pass through a filterprepared by depositing a layer of Kaolin 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 metho
17、d 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 The uniformity and consistency of the Kaolin pastelayer deposited onto the filter pape
18、r;5.5.3 The rate of solution run-out from the pipette; etc. It is,therefore, 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
19、, 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 be rounded andpolished.6.2 Watch Glass, a suitable size (approximately 150 mmdiameter) to be used as a cover fo
20、r 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.) diameter and 15-25 seconddelivery time.6.4 Graduated Cylinder, standard laboratory grade with atleast 225 mL ca
21、pacity.6.5 Glass Rods, soft glass stirring rods with rounded,fire-polished 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 thefollowi
22、ng specifications:6.8.1 Suspend 1.0 g kaolin in 100 mL distilled water. ThepH value should be between 4.5 and 6.0 after 5 min.6.8.2 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 filtra
23、teshould have less than 0.001 g of residue after evaporation andoven-drying 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 maintain
24、ing atemperature of 100 6 2.0C.6.11 Thermometer, accurate to 6 0.2C used to 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 D4905, D4
25、901,orD6405and after passing through the filtering process described in 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 we
26、ll) 25 mL of the well-mixed analyticalsolution (which has been prepared as described in PracticesD4901, D4905,orD6405) 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 mixt
27、ure to a uniform suspension.Immediately pour the suspension onto 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
28、and bottom of the container, and returnto the funnel. During this 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 collectin
29、g and repouring 40 mL of filtrate asmany times as is necessary until 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 th
30、is liquid.8.3 Immediately, refill the kaolin-lined paper in the funnelwith 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
31、into the center ofthe cone along a glass stirring rod contacting 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 containe
32、r and, when about 125 mLhave been collected, remove the container from beneath thefunnel.4The sole source of supply of Stherefore two values for soluble solids will be obtained for eachextract or tanning material. The average (mean) of these valuesshall be taken as the percentage of soluble solids i
33、n 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 as follows:insolubles, % 5 total solids %! 2 soluble solids %! (2)where:total solids (%) is determi
34、ned as in Test Method D4903, 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 is adopted from Method A21 of TheOfficial Methods of the ALCA. This test method has long beenin
35、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 reproducibility) of t
36、histest 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 filtering through the specially con-structed filter system. The insolubles content is defined as thediffe
37、rence between the total solids (Test Method D4903) andthe soluble solids of the sample. There is no independentmeasure of the true soluble solids content or insolubles contentof a sample. Therefore the bias cannot be related to the truesoluble solids or insolubles content of the sample.12. Keywords1
38、2.1 insolubles; soluble solids; tannin analysis; vegetabletannin analysisASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity o
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