1、Designation: D 6016 06Standard Test Method forDetermination of Nitrogen, Water Extractable in Leather1This standard is issued under the fixed designation D 6016; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. 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 covers quantitatively determining thewater extractable nitrogen in leather.1.2 The values given in SI units a
3、re 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 limitat
4、ions prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2868 Test Method for Nitrogen Content (Kjeldahl) andHide Substance Content of LeatherD 2876 Test Method for Water-Soluble Matter of Vegetable-Tanned LeatherD 3495 Test Method for Hexane Extraction of LeatherD 3790 Test Method for Volatil
5、e Matter (Moisture) ofLeather by Oven Drying2.2 Federal Standard:Federal Test Standard No. 311, Method 6452 Nitrogen,Water Extractable33. Significance and Use3.1 This test method provides the means to determinenitrogen containing water extractable materials such as excessand loosely bound tannins, a
6、mmonium salts, and nitrates.4. Apparatus4.1 Volumetric Flask,1L.4.2 Kjeldahl Apparatus, see Test Method D 2868.5. Reagents5.1 See Test Method D 2868.5.2 See Test Method D 3495.5.3 See Test Method D 2876.6. Procedure6.1 Follow the procedure for Test Method D 3495. Saveextracted leather and follow the
7、 procedure in 7.1 only of TestMethod D 2876.6.2 When 1 L has been collected, cool the litre flask withcontents to room temperature, readjusted up to 1 L withdistilled water and mixed thoroughly. Transfer 500 mL of thesolution to an 800-mL Kjeldahl flask. If using automatedKjeldahl instrumentation, s
8、ample size and quantity of reagentsmay need adjustment. Add8gofdigestion catalyst (see TestMethod D 2868) and 20 mL of sulfuric acid (specific gravity1.83) to the solution and the contents of the flask mixedthoroughly.6.3 Digest the mixture over a low heat source until allorganic matter is oxidized
9、as indicated by the end of foamingand clearing of the solution. When foaming has ceased and thesolution has cleared, apply full heat to the mixture and continuedigestion for a minimum of 1 h. After digestion is complete,remove the flask from the heat, and allow to cool to roomtemperature. Then add 2
10、5 mLof 8 % sodium thiosulfate and setaside the flask for 5 to 10 min with occasional stirring.6.4 Follow distillation and titration procedure in 7.3 of TestMethod D 2868.7. Calculation7.1 Calculate the water extractable nitrogen in the specimenas follows:water extractable nitrogen moisture2free basi
11、s!,%5A 3 N 3 0.014 3 2 3 100W 3100 2 M!100!(1)where:A = of standard acid (corrected for blank) required totitrate the specimen, mL,N = normality of the standard acid,W = weight of the specimen, g, andM = moisture content of the leather (see Test MethodD 3790).1This test method is under the jurisdict
12、ion of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.06 on ChemicalAnalysis. Thistest method was developed from Federal Test Method Standard No. 311,Method 6452 in cooperation with the U.S. Army Natick Research Development leather; nitrates; nitrogen; tannins;wate
13、r absorption; water extractableASTM 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 of any such patent rights, and the riskof i
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