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ASTM D4900-99(R2020) pdf free download

ASTM D4900-99(R2020) pdf free download.Standard Test Method for Lignosulfonates (Sulfite Cellulose) in Tanning Extracts
1. Scope
1.1 This test method is intended for use in detecting the presence of lignosulfonates (sulfite cellulose) in extracts of tanning materials. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards: 2 D4901 Practice for Preparation of Solution of Liquid Veg- etable Tannin Extracts D4905 Practice for Preparation of Solution of Solid, Pasty and Powdered Vegetable Tannin Extracts D6404 Practice for Sampling Vegetable Materials Contain- ing Tannin D6405 Practice for Extraction of Tannins from Raw and Spent Materials 2.2 ALCA Methods: A50 Lignosulfonates (Sulfite Cellulose) 3
3. Summary of Test Method
3.1 The reaction with aniline of a tanning material extract specimen is compared with that of a solution containing lignosulfonate and tanning material known to be free from lignosulfonate.
4. Significance and Use
4.1 This test method is useful to detect possible adulteration of tanning material extract with cheap and inferior lignosul- fonates.
5. Specimen
5.1 The sample shall be drawn as described in Practice D6404. 5.2 The specimen shall consist of 5 mL of a solution of analytical strength (4.0 g tannin per L), prepared as described in Practices D4901, D4905, and Practice D6405.
6. Apparatus and Reagents
6.1 Aniline. 6.2 Hydrochloric Acid, concentrated. 6.3 Comparison Solution—This shall contain lignosulfonate (sulfite cellulose) in the proportion of 1 g total solids to 2000 mL ofsolution, and as much tanning material, similar to and of the same type as that being tested but known to be free from lignosulfonate, as will make up the solution to analytical strength.
7. Procedure
7.1 Place the specimen in a test tube. Add 0.5 mL ofaniline, and shake well. Add 2 mL of concentrated hydrochloric acid, and again shake mixture well.
8. Results
8.1 If at least as much precipitate remains at the end of 15 min as is obtained when the comparison solution is similarly treated, the material shall be held to contain lignosulfonates (sulfite cellulose) and the fact shall be noted on the analysis report. 8.2 Attention is drawn to the fact that some synthetic tannins give precipitates under the conditions of this test method.
9. Precision and Bias
9.1 This test method is adopted from the procedures of the American Leather Chemists Association, 3 where it has long been in use and where it was approved for publication before the inclusion of precision and bias statements was mandated. The original interlaboratory test data are no longer available. The user is cautioned to verify by the use of reference materials, if available, that the precision and bias of this test method is adequate for the contemplated use.

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