1、October 2007DEUTSCHE NORM English price group 8No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 59.140.30!$IE“1389134ww
2、w.din.deDDIN EN ISO 5398-3Leather Chemical determination of chromic oxide content Part 3: Quantification by atomic absorption spectrometry(ISO 5398-3:2007)English version of DIN EN ISO 5398-3:2007-10Leder Chemische Bestimmung des Chromoxidgehalts Teil 3: Bestimmung durch Atomabsorptionsspektrometrie
3、 (ISO 5398-3:2007)Englische Fassung DIN EN ISO 5398-3:2007-10www.beuth.deDocument comprises 12 pagesDIN EN ISO 5398-3:2007-10 2 National foreword This standard has been prepared by Technical Committee CEN/TC 289 “Leather” (Secretariat: UNI, Italy), in collaboration with the International Union of Le
4、ather Technologists and Chemists Societies (IULTCS). The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Technical Committee NA 062-05-52 Chemische Prfverfahren fr Leder. This part of ISO 5398 was prepared by the Che
5、mical 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/TC 289, Leather, the secretariat of which is held by UNI, in accordance with the a
6、greement on technical co-operation between ISO and CEN (Vienna Agreement). 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 establish
7、ing international methods for the sampling and testing of leather. ISO recognizes IULTCS as an international standardizing body for the preparation of test methods for leather. EN ISO 5398 consists of the following parts, under the general title Leather Chemical determination of chromic oxide conten
8、t: Part 1: Quantification by 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) The DIN Standards corresponding to the International Stand
9、ards referred to in this document are as follows: ISO 2418 DIN EN ISO 2418 ISO 3696 DIN ISO 3696 ISO 4044 DIN EN ISO 4044 ISO 4684 DIN EN ISO 4684 National Annex NA (informative) Bibliography DIN EN ISO 2418, Leather Chemical, physical and mechanical and fastness tests Sampling location DIN EN ISO 4
10、044, Leather Chemical tests Preparation of chemical test samples DIN EN ISO 4684, Leather Chemical tests Determination of volatile matter DIN ISO 3696, Water for analytical laboratory use Specification and test methods EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 5398-3August 2007ICS 59.140
11、.30English VersionCuir - Dosage chimique de loxyde de chrome - Partie 3:Quantification par spectromtrie dabsorption atomique(ISO 5398-3:2007)Leder - Chemische Bestimmung des Chromoxidgehalts -Teil 3: Bestimmung durch Atomabsorptionsspektrometrie(ISO 5398-3:2007)This European Standard was approved by
12、 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 national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards m
13、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
14、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,
15、 Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any for
16、m and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 5398-3:2007: ELeather - Chemical determination of chromic oxide contentPart 3: Quantification by atomic absorption spectrometry(ISO 5398-3:2007)Contents Page 1 2 3 4 5 6 6.1 6.2 7 8 8.1 8.2 9 10 EN ISO 5398-3:2007 (E)2Scop
17、e 5 Normative references 5 Terms and definitions .5 Sampling and sample preparation.6 Reagents.6 Principle5 Wet oxidation method .6 Apparatus .6 Methods 7 Atomic absorption spectrometry .6 Preparation of analytical solution7 Test report 9 Measurement of the aqueous solution7 Annex A (informative) De
18、termination of water and other volatile matter10 Calculation and expression of results.8 Introduction .4Foreword3EN ISO 5398-3:2007 (E) 3 Foreword This document (EN ISO 5398-3:2007) has been prepared by Technical Committee CEN/TC 289 “Leather”, the secretariat of which is held by UNI, in collaborati
19、on 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 February 2008, and conflicting national standards shall be
20、 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, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany,
21、 Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Introduction ISO 5398 has been split into four parts, each describing methods suitable for the deter
22、mination 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
23、are deemed suitable to quantify. ISO 5398-3 describes a technique that is suitable for determining chromium more precisely than those described in ISO 5398-1 and ISO 5398-2. It requires the use of sophisticated analytical equipment, such as atomic absorption spectroscopy. EN ISO 5398-3:2007 (E)41 Sc
24、ope 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 determination of chromium by atomic a
25、bsorption 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 f
26、ollowing 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 an
27、d 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, Leather Chemical tests Determination of volatile matter EN 14602, Footwear Test methods for the assessm
28、ent of 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
29、per kilogram (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. EN ISO 5398-3:2007 (E)55 Sampling and sample preparation If possible, sample in accordance with IS
30、O 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. Weigh 2 g of the ground leather to the nearest
31、0,001 g. From every leather, a minimum of two determinations shall be made. 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. All solutions are aqueous solutions. 6.1 Wet oxidation method 6.1.1 Nitric acid
32、, 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 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 solu
33、tion: 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 solution 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
34、(6.1.1) to each litre prepared. 7 Apparatus Usual laboratory apparatus is required and, in particular, the following. 7.1 Conical flask, 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
35、oxide burner head. 7.3 Filtration device, using glass fibre (GFC) or membrane type filters. 7.4 Antibumping granules (or similar) (wet oxidation method). EN ISO 5398-3:2007 (E)68 Methods 8.1 Preparation of analytical solution 8.1.1 Wet oxidation method WARNING It is imperative that nitric acid is ad
36、ded 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/perchloric acids (6.1.2) and a few antibump
37、ing 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 2 min. Allow to cool in air for 5
38、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 oxidation (i.e. the solution does not
39、 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, then the procedure described in EN 146
40、02 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 recommended by the manufacturer, then the se
41、ttings 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 high Fuel flow as recommended by manu
42、facturer 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 4,0 g/ml calibration solution. Opti
43、mize 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. EN ISO 5398-3:2007 (E)78.2.2 Preparation of calibration graph Prepare standard solution
44、s by pipetting 10 ml of the standard dichromate solution (6.2.3) into a 100 ml volumetric flask and making up to volume with distilled water. Pipette 2,0 ml, 4,0 ml, 6,0 ml and 8,0 ml aliquots of this solution into 100 ml volumetric flasks and make up to volume with potassium chloride solution (6.2.
45、4). These solutions contain 2,0 g/ml, 4,0 g/ml, 6,0 g/ml and 8,0 g/ml of chromium respectively. Aspirate the standard solutions and prepare a standard calibration curve. This calibration may be retained in the spectrophotometers memory if preferred. 8.2.3 Analysis of the test solution Transfer the c
46、ontents from the analytical solution obtained from 8.1 into a 250 ml volumetric flask and make up to volume with the potassium chloride solution (6.2.4), mixing well. This solution can be analysed directly following filtration (7.3), provided it does not contain more than 7,5 g/ml of chromium. Other
47、wise, the solution should be diluted accordingly. Aspirate the test solution and determine the absorbance obtained. Calculate the concentration of chromium in the solution by use of the standard calibration curve. Note that if the calibration is retained in the spectrophotometers memory, then the re
48、ading may be given directly in terms of concentration. If the absorbance is outside the range of the calibration standards, the analysis should be repeated either using a smaller sample size or with an appropriate dilution of the solution obtained from 8.1.1 or 8.1.2. 9 Calculation and expression of
49、 results Calculate the chromic oxide content in the leather, wCr, expressed in milligrams per kilogram (mg/kg), using the following equation: Cr01,462 VFwm= where is the concentration of chromium determined in 8.2.3, in micrograms per millilitre (g/ml); V is the total volume, in millilitres (ml) (if no additional dilution is required, V = 250 ml); m0is the original mass of leather, in grams (g); 1,462 is the correction factor to convert Cr to Cr2O3;F is the factor to correct to 0 % volatile matter; it is c
