SANS 970-2010 Leather - Determination of nitrogen content and hide substance - Titrimetric method《皮革 氮含量和“隐藏物质”含量的测定 滴定法》.pdf

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3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-22665-7 SANS 970:2010Edition 1ISO 5397:1984Edition 1SOUTH AFRICAN NATIONAL STANDARD Leather Determination of nitrogen content and “hide su

4、bstance“ Titrimetric method This national standard is the identical implementation of ISO 5397:1984 and is adopted with the permission of the International Organization for Standardization. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001Tel: +27 12 42

5、8 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 970:2010 Edition 1 ISO 5399:1984 Edition 1 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee SABS SC 120B, Leather Leather test methods, in accordance with procedures of the SAB

6、S Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in January 2010. International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATlON.MEKfiYHAPOfiHAR OPTAHM3AUMfi n0 CTAHWTM3ALlkI*ORGANlSATlON INTERNATIONALE DE NORMALISATION Leather - Dete

7、rmination of nitrogen content and “hide substance” - Titrimetric method Cuir - Determination de la teneur en azo te et de la ccsubstance dermique) - Mthode titrime trique First edition - 1984-03-15 UDC 675 : 543.846 Ref. No. IS0 5397-1984 (E) Descriptors : leather, tanning, tests, determination of c

8、ontent, nitrogen, volumetric analysis. Price based on 3 pages SANS 970:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodie

9、s (IS0 member bodies). The work of developing International Standards is carried out through IS0 technical committees. Every member body interested in a subject for which a technical committee has been authorized has the right to be represented on that committee. International organizations, governm

10、ental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. International Standard IS0 5397 was d

11、eveloped by Technical Committee Leather, and was circulated to the member bodies in November 1980. ISO/TC 120, It has been approved by the member bodies of the following countries: Australia India Brazil Korea, Rep. of Canada Mexico Czechoslovakia New Zealand Egypt, Arab Rep. of Poland Hungary Portu

12、gal Romania South Africa, Rep. of Spain Turkey United Kingdom USSR The member body technical grounds of the following country expressed disapproval of the document on France This International Standard is based on Method IUC/lO of the International Union of Leather Technologists and Chemists Societi

13、es. 0 International Organization for Standardization, 1984 l Printed in Switzerland SANS 970:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .INTERNATIONAL STANDARD IS0 5397-1984 (E) Leather - Determination of nitrogen content and “hide su

14、bstance” - Titrimetric method 0 introduction The determination of “hide substance” from nitrogen content is based on the fact that, according to Schroder and Passler, the grease- and ash-free dry substance of the pelts of various animals has a somewhat different, but practically constant, nitrogen c

15、ontent for certain types of animal. 4 Principle Decomposition of a test portion by the Kjeldahl method. Distillation of the ammonia liberated, by one of the usual methods. Determination of the nitrogen content by titration of the ammonia with sulfuric or hydrochloric acid, using phenolphthalein as i

16、ndicator. 5 Reagents 1 Scope and field of application This International Standard specifies a titrimetric method for the determination of the nitrogen content and of the “hide substance” of leather. The method is applicable to all types of leather in all types of tannage. NOTE - Other nitrogenous su

17、bstances (e.g. certain fixatives, syn- thetic tannins, cationic fats and dyestuffs) falsify the value for the “hide substance”. If these materials are present, it is not possible to obtain an accurate result for the “hide substance”. During the analysis, use only reagents of recognized analytical gr

18、ade and only distilled water or water of equivalent purity. 5.1 Fuming sulfuric acid, 7 % (m/m) of free SO 8.2 Blank test m is the mass, in grams, of the test portion (8.1). Carry out a blank test at the same time as the determination, following the same procedure and using the same reagents as used

19、 for the determination. Take as the result the mean of two determinations, provided that the requirement for repeatability (see 9.2) is satisfied, and express it to one decimal place. 8.3 Determination 9.1.2 The “hide substance” H, expressed as a percentage by mass, is given by the formula To the te

20、st portion (8.1) in the Kjeldahl flask, add 30 ml of the sulfuric acid (5.1) and approximately 5 g of the catalyst mixture H= N x 5,62 (5.2). Then heat to boiling, first with a low and later with a higher flame, until 1 h after all the carbon has been oxidized. where N is as defined in 9.1.1. 2 SANS

21、 970:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .IS0 5397-1984 (E) 9.2 Repeatability (5.2). Titration of the ammonia is then carried out with acid of one-fifth the concentration specified in 5.5. The results of duplicate determination

22、s carried out by the same operator in the same laboratory shall not differ by more than 0,l %, calculated on the original mass of leather. 11 Test report The test report shall include the following particulars : 10 Notes on procedure a) reference to this International Standard; b) complete identific

23、ation of the sample; 10.1 With the prescribed mass of test portion and using the acid specified in 5.5 for the titration, the end-point is very clear and sharp. c) the results obtained and the method of expression used; d) any unusual features noted during the determination; IO.2 The determination c

24、an also be carried out with 0,5 g of e) any operation not included in this International Stan- leather weighed to 0,000 2 g and 15 to 20 ml of the concentra- dard or the International Standards to which reference is ted or fuming sulfuric acid (5.1) and 2,5 g of the catalyst made, or regarded as opt

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