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 978-0-626-23179-8 SANS 5398-3:2010Edition 1ISO 5398-3:2007Edition 1SOUTH AFRICAN NATIONAL STANDARD Leather Chemical determination of chromic oxide c
4、ontent Part 3: Quantification by atomic absorption spectrometry This national standard is the identical implementation of ISO 5398-3:2007 and is adopted with the permission of the International Organization for Standardization. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Privat
5、e Bag X191 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 5398-3:2010 Edition 1 ISO 5398-3:2007 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 method
6、s, in 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 5398-3:2007(E)IULTCS/IUC 8:3:2007(E)ISO 2007INTERNATIONAL STANDARD ISO5398-3IULTCS/IUC8:3First edition2007-08-01
7、Leather Chemical determination of chromic oxide content Part 3: Quantification by atomic absorption spectrometry Cuir Dosage chimique de loxyde de chrome Partie 3: Quantification par spectromtrie dabsorption atomique SANS 5398-3:2010This s tandard may only be used and printed by approved subscriptio
8、n and freemailing clients of the SABS .ISO 5398-3:2007(E) IULTCS/IUC 8:3:2007(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
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11、s found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2007 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 an
12、d microfilm, without 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
13、 ISO 2007 All rights reservedSANS 5398-3:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5398-3:2007(E) IULTCS/IUC 8:3:2007(E) ISO 2007 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Normative references 1
14、 3 Terms and definitions .1 4 Principle1 5 Sampling and sample preparation.2 6 Reagents.2 6.1 Wet oxidation method .2 6.2 Atomic absorption spectrometry .2 7 Apparatus .2 8 Methods 3 8.1 Preparation of analytical solution3 8.2 Measurement of the aqueous solution3 9 Calculation and expression of resu
15、lts.4 10 Test report 5 Annex A (informative) Determination of water and other volatile matter6 SANS 5398-3:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5398-3:2007(E) IULTCS/IUC 8:3:2007(E) iv ISO 2007 All rights reservedForeword I
16、SO (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 through ISO technical committees. Each member body interested in a subject for which a technical c
17、ommittee 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 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electr
18、otechnical 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 Standards. Draft International Standards adopted by the technical committees are circulated to the m
19、ember 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 of this document may be the subject of patent rights. ISO shall not be held responsible for identi
20、fying any or all such patent rights. This part of ISO 5398 was prepared by the Chemical Tests Commission of the International Union of Leather Technologists and Chemists Societies (IUC Commission, IULTCS) in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/
21、TC 289, Leather, the secretariat of which is held by UNI, in accordance with the agreement on technical co-operation between ISO and CEN (Vienna Agreement). It is based on IUC 8 originally published in J. Soc. Leather Trades Chemists 49, p. 17, (1965) and declared an official method of the IULTCS in
22、 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 for the sampling and testing of leather. I
23、SO 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 titration Part 2: Quantification by colori
24、metric determination Part 3: Quantification by atomic absorption spectrometry Part 4: Quantification by inductively coupled plasma optical emission spectrometer (ICP-OES) SANS 5398-3:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 539
25、8-3:2007(E) IULTCS/IUC 8:3:2007(E) ISO 2007 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 described to reflect the variations in industrial
26、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 5398-3 describes a technique that is suitable for determining chromium more precisely than those d
27、escribed in ISO 5398-1 and ISO 5398-2. It requires the use of sophisticated analytical equipment, such as atomic absorption spectroscopy. SANS 5398-3:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .SANS 5398-3:2010This s tandard may only
28、be used and printed by approved subscription and freemailing clients of the SABS .INTERNATIONAL STANDARD ISO 5398-3:2007(E)IULTCS/IUC 8:3:2007(E) ISO 2007 All rights reserved 1Leather Chemical determination of chromic oxide content Part 3: Quantification by atomic absorption spectrometry 1 Scope Thi
29、s part of ISO 5398 describes a method for the determination of chromium in aqueous solution obtained from leather. This is an analysis for total chromium in leather; it is not compound specific or specific to its oxidation state. This method describes the determination of chromium by atomic absorpti
30、on spectrometry and is applicable to leathers which are expected to have chromic oxide contents in excess of 5 mg/kg. Two techniques for the preparation of the solution to be analysed are included. In the case of dispute, the wet oxidation technique is to be used. 2 Normative references The followin
31、g referenced documents are indispensable for the application of this document. 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 fastn
32、ess tests Sampling location ISO 3696:1987, Water for analytical laboratory use Specification and test methods ISO 4044, Leather Chemical tests Preparation of chemical test samples ISO 4684, Leather Chemical tests Determination of volatile matter EN 14602, Footwear Test methods for the assessment of
33、ecological criteria 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 chromic oxide content amount of chromium in leather, determined by this method and reported as chromic oxide NOTE The chromic oxide content is expressed in milligrams per kil
34、ogram (mg/kg), based on dry matter. 4 Principle The chromium present in the leather is solubilized in the hexavalent state followed by analysis of the solution by atomic absorption spectrometry. SANS 5398-3:2010This s tandard may only be used and printed by approved subscription and freemailing clie
35、nts of the SABS .ISO 5398-3:2007(E) IULTCS/IUC 8:3:2007(E) 2 ISO 2007 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 (as in the case of leather
36、s from finished products like shoes, garments), details about sampling shall be given together with the test report. Weigh 2 g of the ground leather to the nearest 0,001 g. From every leather, a minimum of two determinations shall be made. 6 Reagents Unless otherwise stated, only analytical grade ch
37、emicals are to be used. The water shall be grade 3 in accordance with ISO 3696:1987. All solutions are aqueous solutions. 6.1 Wet oxidation method 6.1.1 Nitric acid, 70 %. 6.1.2 Sulfuric acid, concentrated (98 %), and perchloric acid (60 % to 70 %), mixed together in the ratio of 1:3 by volume. 6.2
38、Atomic absorption spectrometry 6.2.1 Potassium dichromate (K2Cr2O7), dried for 16 h 2 h at 102 C 2 C. 6.2.2 Potassium chloride (KCl). 6.2.3 Standard dichromate solution: dissolve 2,829 g of potassium dichromate (6.2.1) in water in a volumetric flask and make up to 1 000 ml with water. 1 ml of this s
39、olution contains 1 mg of chromium. 6.2.4 Potassium chloride solution: dissolve 2 g of potassium chloride (6.2.2) in 1 l of distilled water. Add 1 ml of nitric acid (6.1.1) to each litre prepared. 7 Apparatus Usual laboratory apparatus is required and, in particular, the following. 7.1 Conical flask,
40、 500 ml, with ground glass stopper. 7.2 Atomic absorption spectrophotometer, with suitable hollow cathode lamp and nitrous oxide burner head or high solids nitrous oxide burner head. 7.3 Filtration device, using glass fibre (GFC) or membrane type filters. 7.4 Antibumping granules (or similar) (wet o
41、xidation method). SANS 5398-3:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5398-3:2007(E) IULTCS/IUC 8:3:2007(E) ISO 2007 All rights reserved 38 Methods 8.1 Preparation of analytical solution 8.1.1 Wet oxidation method WARNING It i
42、s imperative that nitric acid is added first because of the possible explosive reaction of perchloric acid with leather. Accurately weigh a mass of leather (see Clause 5) into the conical flask (7.1). Add 10 ml of nitric acid (6.1.1) and allow to stand for 2 min. Add 15 ml of mixed sulfuric/perchlor
43、ic acids (6.1.2) and a few antibumping granules (7.4). Place a funnel or splash bulb in the neck of the flask and heat to boiling on a wire gauze over a moderate flame. As soon as the reaction mixture begins to turn orange, lower the flame. After a complete change of colour, heat gently for at least
44、 2 min. Allow to cool in air for 5 min and dilute to approximately 200 ml. Boil for 10 min to eliminate any chlorine. The use of a sulfuric/perchloric acid mixture is preferred to the use of the individual acids as it prevents the accidental use of perchloric acid alone. In the case of incomplete ox
45、idation (i.e. the solution does not change to an orange colour), it is permissible to add further mixed sulfuric/perchloric acid to the sample. 8.1.2 Microwave digestion The sample for analysis can also be prepared through application of microwave-assisted digestion (MAD). If this is to be used, the
46、n the procedure described in EN 14602 shall be followed. 8.2 Measurement of the aqueous solution 8.2.1 General Prepare the atomic absorption spectrophotometer (7.2) by following the manufacturers instructions for adjusting all instrument parameters. Where it is noted that the setting is as recommend
47、ed by the manufacturer, then the settings used should be those described by the manufacturer for chromium. Lamp current as recommended by manufacturer Slit width/band pass 0,5 nm Wavelength 357,9 nm Burner head single slot nitrous oxide or high solids nitrous oxide to give red cone 10 mm to 20 mm hi
48、gh Fuel flow as recommended by manufacturer Oxidant flow as recommended by manufacturer Photomultiplier voltage as required to give optimum signal/noise ratio Before carrying out the spectrometric measurements, set up the spectrophotometer according to the manufacturers instructions by aspirating a
49、4,0 g/ml calibration solution. Optimize the aspiration and flame conditions (aspiration rate, nature of the flame, positions of the optical beam in the flame). Aspirate distilled water and adjust controls to give a steady zero (base-line) reading. SANS 5398-3:2010This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 5398-3:2007(E) IULTCS/IUC 8:3:2007(E) 4 ISO 2007 All rights reserved8.2.2 Preparation of calibration graph Prepare standard
