BS EN ISO 5398-2-2009 Leather Chemical determination of chromic oxide content Quantification by colorimetric determination《皮革 氧化铬含量的化学测定 用比色测定数量》.pdf

1、BS EN ISO5398-2:2009ICS 59.140.30NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDLeather Chemicaldetermination ofchromic oxide contentPart 2: Quantification by colorimetricdetermination (ISO 5398-2:2009)This British Standardwas published under theauthority of th

2、e StandardsPolicy and StrategyCommittee on 28 February BSI 2009ISBN 978 0 580 55575 6Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 5398-2:2009National forewordThis British Standard is the UK implementation of EN ISO 5398-2:2009.The UK participation in its preparation was entru

3、sted to TechnicalCommittee TCI/69, Footwear, leather and coated fabrics.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct appli

4、cation.Compliance with a British Standard cannot confer immunityfrom legal obligations.2009EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 5398-2January 2009ICS 59.140.30English VersionLeather - Chemical determination of chromic oxide content - Part2: Quantification by colorimetric determinati

5、on (ISO 5398-2:2009)Cuir - Dosage chimique de loxyde de chrome - Partie 2:Quantification par dosage colorimtrique (ISO 5398-2:2009)Leder - Chemische Bestimmung des Chromoxidgehaltes -Teil 2: Gehaltsbestimmung durch kolorimetrischeBestimmung (ISO 5398-2:2009)This European Standard was approved by CEN

6、 on 19 December 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards m

7、ay 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 in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CE

8、N Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,

9、 Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form

10、and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 5398-2:2009: EBS EN ISO 5398-2:2009EN ISO 5398-2:2009 (E) 3 Foreword This document (EN ISO 5398-2:2009) has been prepared by Technical Committee CEN/TC 289 “Leather“, the secretariat of which is held by UNI, in collaboration

11、 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 endorsement, at the latest by July 2009, and conflicting national standards shall be withd

12、rawn at the latest by July 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, th

13、e national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, No

14、rway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN ISO 5398-2:2009ISO 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 definitio

15、ns. 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 analyti

16、cal 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 BS EN ISO 5398-2:2009ISO 5398-2:2009(E) IULTCS/IUC 8:2:2009(E) iv ISO 2009 All rights reservedForeword ISO (the

17、 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 committe

18、e 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 electrotechni

19、cal 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 member b

20、odies 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 identifying a

21、ny 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 Commission of the International Union of Leather Technologists and Chemists Societies (IUC Commission, IULTCS),

22、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 declared an official method of the IULTCS in 1965. IULTCS, originally formed in 1897, is a world-wide organ

23、ization 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. ISO recognizes IULTCS as an international standardizing body for

24、 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 colorimetric determination Part 3: Quantification by atomic absorptio

25、n spectrometry Part 4: Quantification by inductively coupled plasma optical emission spectrometer (ICP-OES) BS EN ISO 5398-2:2009ISO 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 dete

26、rmination 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 of chromic oxide that the methods

27、 are deemed suitable to quantify. ISO 5398-2 describes a colorimetric technique that requires the use of a spectrophotometer. BS EN ISO 5398-2:2009BS EN ISO 5398-2:2009INTERNATIONAL STANDARD ISO 5398-2:2009(E)IULTCS/IUC 8:2:2009(E) ISO 2009 All rights reserved 1Leather Chemical determination of chro

28、mic 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 which are expected to have chromic oxide contents in excess of 0,05 %. This is an analysis for total chromium

29、 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. For dated references, only the edition cited applies. For undated references, the latest edition of the refer

30、enced 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 Specification and test methods ISO 4044, Leather Chemical tests Preparation of chemical test samples ISO 4684

31、, 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 The chromic oxide cont

32、ent 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 hexavalent state followed by analysis of the solution after reaction with 1,5-diphenyl carbazide to diphenyl c

33、arbazone by photometric means. BS EN ISO 5398-2:2009ISO 5398-2:2009(E) IULTCS/IUC 8:2:2009(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

34、possible (e.g. leathers from finished products like shoes, garments), details about sampling 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 dete

35、rminations using separate leather portions. 6 Reagents Unless otherwise stated, only analytical 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), potas

36、sium carbonate (K2CO3) and sodium tetraborate (Na2B4O7). 6.2 Photometric determination 6.2.1 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, pr

37、epared from 50 ml of stock solution (6.2.2) pipetted into a 250 ml volumetric flask and made 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

38、glacial acetic acid added. This can be stored for up to two weeks at 4 C. 6.2.5 Acetone. 6.2.6 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

39、porcelain or platinum. 7.2 Spectrophotometer, capable of reading absorbance to a minimum of 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. BS EN ISO 5398-2:2009ISO 5398-2:2009(E) IULTCS/IUC 8:2:2

40、009(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 fusion mixtur

41、e (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 the crucib

42、le 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 the beaker,

43、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 1 is reache

44、d, 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 solution Add 10 m

45、l, 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 carried ou

46、t (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 cuvette. If the

47、 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 potassium dichr

48、omate (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 BS EN ISO 5398-2:2009ISO 5398-2:2009(E) IULTCS/IUC 8:2:2009(E) 4 ISO 2009 All rights reservedAdd 1 ml

49、 of sulfuric acid (6.2.1) to each flask followed by 1 ml of diphenyl carbazide solution (6.2.4). Make up each flask to volume with distilled water and inverted several times to mix thoroughly. Prepare a calibration graph by plotting the absorbance against the Cr2O3content in milligrams per 100 ml (mg/100 ml). 9 Check of the analytical system Upon each set of analysis or on a daily basis (whichever is the least frequent), a solution prepared from 5 ml standard solution (6.2.3) should be evaluated accordin