1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
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 978-0-626-23178-1 SANS 5398-2:2010Edition 1ISO 5398-2:2009Edition 1SOUTH AFRICAN NATIONAL STANDARD Leather Chemical determination of chromic oxide c
4、ontent Part 2: Quantification by colorimetric determination This national standard is the identical implementation of ISO 5398-2:2009 and is adopted with the permission of the International Organization for Standardization. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Ba
5、g X191 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 5398-2:2010 Edition 1 ISO 5398-2:2009 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, i
6、n accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in January 2010. Reference numberISO 5398-2:2009(E)IULTCS/IUC 8:2:2009(E)ISO 2009INTERNATIONAL STANDARD ISO5398-2IULTCS/IUC8:2First edition2009-01-15Leat
7、her Chemical determination of chromic oxide content Part 2: Quantification by colorimetric determination Cuir Dosage chimique de loxyde de chrome Partie 2: Quantification par dosage colorimtrique SANS 5398-2:2010This s tandard may only be used and printed by approved subscription and freemailing cli
8、ents of the SABS .ISO 5398-2:2009(E) IULTCS/IUC 8:2:2009(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the
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11、m the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2009 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without
12、permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2009 All rights
13、reservedSANS 5398-2:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5398-2:2009(E) IULTCS/IUC 8:2:2009(E) ISO 2009 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and defi
14、nitions. 1 4 Principle. 1 5 Sampling and sample preparation 2 6 Reagents 2 6.1 Alkaline fusion method 2 6.2 Photometric determination 2 7 Apparatus 2 8 Methods . 3 8.1 Alkaline fusion method 3 8.2 Measurement of the aqueous solution. 3 8.3 Preparation of the calibration solution. 3 9 Check of the an
15、alytical system . 4 10 Calculation and expression of results 4 10.1 General. 4 10.2 Repeatability 4 11 Test report . 5 Annex A (informative) Determination of water and other volatile matter . 6 SANS 5398-2:2010This s tandard may only be used and printed by approved subscription and freemailing clien
16、ts of the SABS .ISO 5398-2:2009(E) IULTCS/IUC 8:2:2009(E) iv ISO 2009 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out
17、 through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO col
18、laborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International S
19、tandards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements
20、 of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 5398-2 was prepared by the European Committee for Standardization (CEN) Technical Committee CEN/TC 289, Leather, in collaboration with the Chemical Tests Commis
21、sion of the International Union of Leather Technologists and Chemists Societies (IUC Commission, IULTCS), in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement). It is based on IUC 8 originally published in J. Soc. Leather Tech. Chem., 49, p. 17, 1965, and d
22、eclared an official method of the IULTCS in 1965. IULTCS, originally formed in 1897, is a world-wide organization of professional leather societies to further the advancement of leather science and technology. IULTCS has three Commissions, which are responsible for establishing international methods
23、 for the sampling and testing of leather. ISO recognizes IULTCS as an international standardizing body for the preparation of test methods for leather. ISO 5398 consists of the following parts, under the general title Leather Chemical determination of chromic oxide content: Part 1: Quantification by
24、 titration Part 2: Quantification by colorimetric determination Part 3: Quantification by atomic absorption spectrometry Part 4: Quantification by inductively coupled plasma optical emission spectrometer (ICP-OES) SANS 5398-2:2010This s tandard may only be used and printed by approved subscription a
25、nd freemailing clients of the SABS .ISO 5398-2:2009(E) IULTCS/IUC 8:2:2009(E) ISO 2009 All rights reserved vIntroduction ISO 5398 has been split into four parts, each describing methods suitable for the determination of the chromic oxide content in leather. The different techniques have been describ
26、ed to reflect the variations in industrial practice compared with the more sensitive analytical equipment available for test laboratories. Variations also exist in the range of chromic oxide that the methods are deemed suitable to quantify. ISO 5398-2 describes a colorimetric technique that requires
27、 the use of a spectrophotometer. SANS 5398-2:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .SANS 5398-2:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .INTERNATIONAL STANDARD
28、ISO 5398-2:2009(E)IULTCS/IUC 8:2:2009(E) ISO 2009 All rights reserved 1Leather Chemical determination of chromic oxide content Part 2: Quantification by colorimetric determination 1 Scope This part of ISO 5398 describes the determination of chrome by colorimetric means. It is applicable to leathers
29、which are expected to have chromic oxide contents in excess of 0,05 %. This is an analysis for total chromium in leather; it is not compound specific or specific to its oxidation state. 2 Normative references The following referenced documents are indispensable for the application of this document.
30、For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2418, Leather Chemical, physical and mechanical and fastness tests Sampling location ISO 3696:1987, Water for analytical laboratory use
31、Specification and test methods ISO 4044, Leather Chemical tests Preparation of chemical test samples ISO 4684, Leather Chemical tests Determination of volatile matter 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 chromic oxide content amoun
32、t of chromium in leather, determined by this method and reported as chromic oxide NOTE The chromic oxide content is expressed in percentage by mass, based on dry matter. 4 Principle Ash obtained from leather is fused by an alkaline mixture. The chromium present in the leather is solubilized in the h
33、exavalent state followed by analysis of the solution after reaction with 1,5-diphenyl carbazide to diphenyl carbazone by photometric means. SANS 5398-2:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5398-2:2009(E) IULTCS/IUC 8:2:2009
34、(E) 2 ISO 2009 All rights reserved5 Sampling and sample preparation If possible, sample in accordance with ISO 2418 and grind leather in accordance with ISO 4044. If sampling in accordance with ISO 2418 is not possible (e.g. leathers from finished products like shoes, garments), details about sampli
35、ng shall be given together with the test report. Weigh accurately 0,75 g of the ground leather, depending on the expected content of chrome, to the nearest 0,001 g. From each leather, make a minimum of two determinations using separate leather portions. 6 Reagents Unless otherwise stated, only analy
36、tical grade chemicals are to be used. The water shall be grade 3 in accordance with ISO 3696:1987. 6.1 Alkaline fusion method 6.1.1 Fusion mixture, consisting of equal masses of sodium carbonate (Na2CO3), potassium carbonate (K2CO3) and sodium tetraborate (Na2B4O7). 6.2 Photometric determination 6.2
37、.1 Sulfuric acid, 98 %. 6.2.2 Potassium dichromate stock solution (0,2 mg Cr2O3/ml), prepared from 0,387 1 g potassium dichromate (6.2.7) in 1 l distilled water. 6.2.3 Potassium dichromate standard solution, prepared from 50 ml of stock solution (6.2.2) pipetted into a 250 ml volumetric flask and ma
38、de to volume with distilled water. (1 ml of this solution contains 0,04 mg Cr2O3.) 6.2.4 Diphenyl carbazide solution, consisting of 1,00 g of 1,5-diphenyl carbazide dissolved in 100 ml acetone with one drop of glacial acetic acid added. This can be stored for up to two weeks at 4 C. 6.2.5 Acetone. 6
39、.2.6 Glacial acetic acid, 100 %. 6.2.7 Potassium dichromate (K2Cr2O7), dried for 16 h 2 h at 102 C 2 C 7 Apparatus Usual laboratory apparatus is required and, in particular, the following. 7.1 Crucible, glazed porcelain or platinum. 7.2 Spectrophotometer, capable of reading absorbance to a minimum o
40、f 3 decimal places at a wavelength of 540 nm. 7.3 Cuvettes, of 1 cm optical path length. 7.4 Muffle furnace. 7.5 Filtration device, using ash-free paper. SANS 5398-2:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5398-2:2009(E) IULTC
41、S/IUC 8:2:2009(E) ISO 2009 All rights reserved 38 Methods 8.1 Alkaline fusion method Pre-ash the accurately weighed sample of leather (see Clause 5) using an open flame prior to ashing and afterwards ash at 750 C 50 C for 4 h. In the crucible (7.1) containing the leather ash, carefully add 5 g of fu
42、sion mixture (6.1.1) and mix well using a platinum wire or thin glass rod. Initially heat the crucible gently on an open flame, then heat more fiercely for approximately 30 min. (A muffle furnace operating at 750 C 50 C for approximately 30 min may be used for heating the melt.) After cooling, place
43、 the crucible in a beaker containing 100 ml to 150 ml of hand-warm water and continue to heat in the water until the fusion mixture has completely dissolved. No losses of the solution due to splashing shall occur. Filter (7.5) the solution obtained into a 1 000 ml volumetric flask. Thoroughly wash t
44、he beaker, crucible and filter with hot water, collecting the washings in the volumetric flask. If a green residue is observed in the filter, this shall be ashed as described above with the filtrate being added to the 1 000 ml flask. Carefully add at least enough sulfuric acid to the flask until pH
45、1 is reached, allow to cool down to room temperature and make up to volume with distilled water. The resulting solution is stable for 4 days if stored in the dark for samples in excess of 0,5 % Cr2O3. For lower concentrations, analysis shall be done immediately. 8.2 Measurement of the aqueous soluti
46、on Add 10 ml, up to 50 ml from leather with an expected low chromium content, of the solution (8.1) to a 100 ml volumetric flask. Add 1 ml of diphenyl carbazide solution (6.2.4). Make up to volume with distilled water and invert several times to mix thoroughly. The colorimetric measurement should be
47、 carried out (15 5) min after the addition of the diphenyl carbazide solution. Measure the absorbance of the test solution against a blank solution prepared using 25 ml distilled water rather than the sample, 1 ml sulfuric acid and 1 ml diphenyl carbazide solution (6.2.4) at 540 nm using a 1 cm cuve
48、tte. If the absorbance is in excess of that observed from the highest calibration standard, the analysis should be repeated using either smaller sample size, or with appropriate dilution of the solution obtained from 8.1. 8.3 Preparation of the calibration solution From the standard solution of pota
49、ssium dichromate (6.2.3), add the volumes given in the Table 1 to separate 100 ml volumetric flasks. Table 1 Volumes needed Concentration Vstandardmg Cr2O3/100 ml ml 0,02 0,5 0,04 1 0,08 2 0,16 4 0,24 6 0,28 7 SANS 5398-2:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5398-2:2009(E) IULTCS/IUC 8:2:2009(E) 4 ISO 2009 All rights reservedAdd 1 ml of sulfuric acid (6.2.1) to each flask followed by 1 ml of diphenyl carbazide so
