1、BRITISH STANDARDBS EN ISO 5398-1:2007Leather Chemical determination of chromic oxide content Part 1: Quantification by titrationThe European Standard EN ISO 5398-1:2007 has the status of a British StandardICS 59.140.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g5
2、4g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 5398-1:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2007 BSI 2007ISBN 978 0 580 55574 9National
3、 forewordThis British Standard is the UK implementation of EN ISO 5398-1:2007. The UK participation in its preparation was entrusted to Technical Committee TCI/69, Footwear, leather and coated fabrics.A list of organizations represented on this committee can be obtained on request to its secretary.T
4、his publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME E
5、UROPENNEEUROPISCHE NORMEN ISO 5398-1August 2007ICS 59.140.30English VersionLeather - Chemical determination of chromic oxide content - Part1: Quantification by titration (ISO 5398-1:2007)Cuir - Dosage chimique de loxyde de chrome - Partie 1:Quantification par titrage (ISO 5398-1:2007)Leder - Chemisc
6、he Bestimmung des Chromoxidgehalts -Teil 1: Bestimmung durch Titration (ISO 5398-1:2007)This European Standard was approved by CEN on 28 July 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a
7、 national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version
8、in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark,
9、Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROP
10、ISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 5398-1:2007: EForeword This document (EN ISO 5398-1:2007) has been prepared by Technical Committ
11、ee CEN/TC 289 “Leather“, the secretariat of which is held by UNI, in collaboration with the International Union of Leather Technologists and Chemists Societies (IULTCS). This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsem
12、ent, at the latest by February 2008, and conflicting national standards shall be withdrawn at the latest by February 2008. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgiu
13、m, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN ISO 5398-1:2007IU
14、LTCS/IUC 8:1:2007Reference numberISO 5398-1:2007(E)IULTCS/IUC 8:1:2007(E)INTERNATIONAL STANDARD ISO5398-1IULTCS/IUC8:1First edition2007-08-01Leather Chemical determination of chromic oxide content Part 1: Quantification by titration Cuir Dosage chimique de loxyde de chrome Partie 1: Quantification p
15、ar titrage EN ISO 5398-1:2007IULTCS/IUC 8:1:2007ii iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Normative references 1 3 Terms and definitions .1 4 Principle1 5 Sampling and sample preparation.2 6 Reagents.2 6.1 Wet oxidation method .2 6.2 Alkaline fusion method .2 6.3 Iodometric titratio
16、n 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 results.4 9.1 General4 9.2 Repeatability.4 10 Test report 4 Annex A (informative) Determination of water and other volatile matter5 EN ISO 5398-1:2007IULTCS
17、/IUC 8:1:2007iv Foreword 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 through ISO technical committees. Each member body interested in a subje
18、ct 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 collaborates closely with the International Electrotechnical Commission (IEC
19、) 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 Standards. Draft International Standards adopted by the technical committe
20、es 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 of this document may be the subject of patent rights. ISO shall not be h
21、eld responsible for identifying 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
22、) Technical Committee CEN/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 offici
23、al 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 for the sampling
24、 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 titration Part 2
25、: Quantification by colorimetric determination Part 3: Quantification by atomic absorption spectrometry Part 4: Quantification by inductively coupled plasma optical emission spectrometer (ICP-OES) EN ISO 5398-1:2007IULTCS/IUC 8:1:2007vIntroduction ISO 5398 has been split into four parts, each descri
26、bing methods suitable for the determination of the chromic oxide content in leather. The different techniques have been described to reflect the variations in industrial practice compared with the more sensitive analytical equipment available for test laboratories. Variations also exist in the range
27、 of chromic oxide that the methods are deemed suitable to quantify. ISO 5398-1 describes a traditional technique applied in industry that does not require the use of advanced analytical equipment. EN ISO 5398-1:2007IULTCS/IUC 8:1:2007blank1Leather Chemical determination of chromic oxide content Part
28、 1: Quantification by titration 1 Scope This 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 d
29、etermination of chrome by iodometric titration and is to be applicable to chromium-tanned leathers which are expected to have chromic oxide contents in excess of 0,3 %. Two different methods are described as alternatives for obtaining chromium in a suitable solution. It is appropriate to use either
30、method. 2 Normative references The following 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
31、Chemical, physical and mechanical and fastness 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 4047, Leather Determination of sulphated total ash and sulphated water-in
32、soluble ash 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 amount of chromium in leather, determined by this method and reported as chromic oxide NOTE Th
33、e chromic oxide content is expressed in percentage by mass, 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 iodometric titration. EN ISO 5398-1:2007IULTCS/IUC 8:1:20072 5 Sampling and sample preparati
34、on 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 leathers from finished products like shoes, garments), details about sampling shall be given together with the test report. Wei
35、gh accurately the ground leather to the nearest 0,001 g. (Suggested masses are full chrome leather 1 g, semi-chrome leather 2 g, leather with low chrome content 2 g to 5 g.) From every leather, a minimum of two determinations shall be made. 6 Reagents Unless otherwise stated, only analytical grade c
36、hemicals 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. 6.1
37、.3 Orthophosphoric acid, 90 %. 6.2 Alkaline fusion method 6.2.1 Fusion mixture, consisting of equal masses of sodium carbonate (Na2CO3), potassium carbonate (K2CO3) and sodium tetraborate (Na2B4O7). 6.2.2 Hydrochloric acid, concentrated (37 %). 6.3 Iodometric titration 6.3.1 Potassium iodide solutio
38、n, freshly prepared, 100 g/l. 6.3.2 Sodium thiosulfate, 0,1 mol/l standardized solution in water. 6.3.3 Starch indicator solution, 10 g/l (or soluble starch powder). 7 Apparatus Usual laboratory apparatus is required and, in particular, the following. 7.1 Conical flask, 500 ml, with ground glass sto
39、pper. 7.2 Crucible, glazed porcelain or platinum (required for alkaline fusion method only). 7.3 Burette, 50 ml. 7.4 Filtration device, using simple paper, glass fibre (GFC) or membrane type filters. 7.5 Antibumping granules (or similar) (wet oxidation method). EN ISO 5398-1:2007IULTCS/IUC 8:1:20073
40、8 Methods 8.1 Preparation of analytical solution 8.1.1 Wet oxidation method WARNING It is 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 o
41、f nitric acid (6.1.1) and allow to stand for 2 min. Add 15 ml of mixed sulfuric/perchloric acids (6.1.2) and a few antibumping granules (7.5). 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 t
42、urn orange, lower the flame. After a complete change of colour, heat gently for at least 2 min. Allow to cool in air for 5 min and dilute to approximately 200 ml. Boil for 10 min to eliminate any chlorine. Allow to cool and add 5 ml of orthophosphoric acid (6.1.3) to mask any iron. The use of a sulf
43、uric/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 oxidation (i.e. the solution does not change to an orange colour), it is permissible to add further mixed sulfuric/perchloric acid to the
44、 sample. 8.1.2 Alkaline fusion method Ash the accurately weighed sample of leather (see Clause 5) in accordance with ISO 4047. In the crucible (7.2) containing the leather ash, carefully add 5 g of fusion mixture (6.2.1) and mix well using a platinum wire or thin glass rod. Start by heating the cruc
45、ible gently on an open flame, then heat more fiercely for approximately 30 min. (A muffle furnace operating at 750 C 50 C for at least 30 min may be used to heart the melt). After cooling, place the crucible in a beaker containing 100 ml to 150 ml of boiling water and continue to heat the water unti
46、l the fusion mixture has completely dissolved. Filter (7.4) the solution obtained into the conical flask (7.1). Thoroughly wash the beaker, crucible and filter with hot water collecting the washings in the flask. Carefully add at least 10 ml hydrochloric acid to the flask and allow to cool down to r
47、oom temperature. 8.2 Measurement of the aqueous solution Add to the solution obtained from 8.1.1 or 8.1.2 20 ml of potassium iodide solution (6.3.1), stopper the flask and leave to stand for 10 min in the dark. Titrate with 0,1 mol/l sodium thiosulfate solution (6.3.2) until the solution in the flas
48、k is either light green or blue using 5 ml of starch indicator solution (6.3.3) (or a small quantity of starch powder), added towards the end of titration. Note the millilitres of thiosulfate solution used. If starch solution is used, it should either be freshly prepared or should have been prepared
49、 with the addition of a little mercuric iodide to preserve the solution for several months. If the titre is in excess of 50 ml, the analysis should be repeated using either smaller sample size or with appropriate dilution of the solution obtained from 8.1.1 or 8.1.2. EN ISO 5398-1:2007IULTCS/IUC 8:1:20074 9 Calculation and expression of results 9.1 General Calculate the following percentage. The percentage by mass on dry matter, wCr, of chromic oxide, Cr2O3, in the leather is given by the equation 1Cr00,002 53 100VFwm= where V1is t
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