1、BS EN ISO17226-2:2008ICS 59.140.30NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDLeather Chemicaldetermination offormaldehyde contentPart 2: Method using colorimetricanalysis (ISO 17226-2:2008)Incorporating corrigendum April 2009National forewordThis British St
2、andard is the UK implementation of EN ISO 17226-2:2008. It is identical to ISO 17226-2:2008, incorporating corrigendum April 2009. Together with BS EN ISO 17226-1:2008 it supersedes DD CEN ISO/TS 17226:2003which is withdrawn.The UK participation in its preparation was entrusted by Technical Committe
3、e TCI/69, Footwear, leather and coated fabrics.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with
4、a British Standard cannot confer immunity from legal obligations.BS EN ISO 17226-2:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2009 BSI 2010Amendments/corrigenda issued since publicationDateComments 31 January 2010 Implementati
5、on of ISO corrigendum April 2009. Equation replaced in 7.2.7ISBN 978 0 580 68266 7EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORMEN ISO 17226-2May 2008ICS 59.140.30 English VersionLeather - Chemical determination of formaldehyde content - Part 2: Method using colorimetric analysis (ISO 17226-2:200
6、8)Cuir - Dosage chimique du formaldhyde - Partie 2: Mthode par analyse colorimtrique (ISO 17226-2:2008)Leder - Chemische Prfungen - Teil 2: Bestimmung des Formaldehydgehalts in Leder durch kolorimetrischeAnalyse (ISO 17226-2:2008)This European Standard was approved by CEN on 26 April 2008.CEN member
7、s are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application
8、 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 translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the
9、same status as the official 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, Norway, Poland, Portugal,
10、 Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means rese
11、rved worldwide for CEN national Members.Ref. No. EN ISO 17226-2:2008: EIncorporating corrigendum April 2009BS EN ISO 17226-2:2008EN ISO 17226-2:2008 (E) 3 Foreword This document (EN ISO 17226-2:2008) has been prepared by Technical Committee CEN/TC 289 “Leather“, the secretariat of which is held by U
12、NI in collaboration with Technical Committee ISO/TC IULTCS “International Union of Leather Technologists and Chemists Societies“. 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 November 2008, and
13、 conflicting national standards shall be withdrawn at the latest by November 2008. 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. Acc
14、ording 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, Greece, Hungary, Iceland, Ireland, Italy, Lat
15、via, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. IULTCS/IUC 19-2:2008(E) ISO 17226-2:2008(E) IULTCS/IUC 19-2:2008(E) ISO 2009 All rights reserved iiiForeword ISO (the International Organization f
16、or 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 committee has been established has th
17、e 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 electrotechnical standardization. Internat
18、ional 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 bodies for voting. Publication
19、 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 any or all such patent rights.
20、 ISO 17226-2 was prepared by the European Committee for Standardization (CEN) Technical Committee CEN/TC 289, Leather, in collaboration with the Chemical Test Commission of the International Union of Leather Technologists and Chemists Societies (IUC Commission, IULTCS), in accordance with the Agreem
21、ent on technical cooperation between ISO and CEN (Vienna Agreement). This method is technically similar to the Colorimetric Section of the method IUC 19 which was declared an official method at the IULTCS Delegates meeting on 31st May 2003 in Cancn, Mexico. IULTCS, originally formed in 1897, is a wo
22、rld-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 sampling and the testing of leather. ISO recognizes IULTCS as an international standard
23、izing body for the preparation of test methods for leather. This first edition of ISO 17226-2, together with ISO 17226-1, cancels and replaces ISO/TS 17226:2003, which has been technically revised. ISO 17226 consists of the following parts, under the general title Leather Chemical determination of f
24、ormaldehyde content: Part 1: Method using high performance liquid chromatography Part 2: Method using colorimetric analysis BS EN ISO 17226-2:2008BS EN ISO 17226-2:2008INTERNATIONAL STANDARD ISO 17226-2:2008(E)IULTCS/IUC 19-2:2008(E) ISO 2009 All rights reserved 1Leather Chemical determination of fo
25、rmaldehyde content Part 2: Method using colorimetric analysis 1 Scope This part of ISO 17226 specifies a method for the determination of free and released formaldehyde in leathers. This method is based on colorimetric analysis. The formaldehyde content is taken to be the quantity of free-formaldehyd
26、e and formaldehyde extracted through hydrolysis contained in a water extract from the leather under standard conditions. This process is not absolutely selective for formaldehyde. Other compounds such as extracted dyes could interfere at 412 nm. 2 Conformance When compared with ISO 17226-1, the two
27、analytical methods should give similar trends but not necessarily the same absolute result. Therefore, in the case of dispute, ISO 17226-1 shall be used in preference. 3 Normative references The following referenced documents are indispensable for the application of this document. For dated referenc
28、es, 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 Specification and
29、test methods ISO 4044, Leather Chemical tests Preparation of chemical test samples ISO 4684, Leather Chemical tests Determination of volatile matter ISO 17226-1, Leather Chemical determination of formaldehyde content Part 1: Method using high performance liquid chromatography 4 Principle The leather
30、 sample is eluted with detergent solution at 40 C. The eluate is treated with acetylacetone, whereby formaldehyde reacts to give a yellow compound (3,5-diacetyl-1,4-dihydrolutidine). The absorbance of this compound is measured at 412 nm. The amount of formaldehyde corresponding to the absorbance val
31、ue for the test specimen is obtained from a calibration curve prepared under identical conditions. BS EN ISO 17226-2:2008BS EN ISO 17226-2:2008ISO 17226-2:2008(E) IULTCS/IUC 19-2:2008(E) 2 ISO 2009 All rights reserved5 Reagents Use only reagents of recognized analytical grade, unless otherwise state
32、d. The water shall be grade 3 in accordance with ISO 3696:1987. All solutions are aqueous solutions. 5.1 Reagents for the formaldehyde stock solution 5.1.1 Formaldehyde solution, approximately 37 % mass fraction. 5.1.2 Iodine solution, 0,05 mol/l, i.e. 12,68 g iodine per litre. 5.1.3 Sodium hydroxid
33、e solution, 2,0 mol/l. 5.1.4 Sulfuric acid solution, 2,0 mol/l. 5.1.5 Sodium thiosulfate solution, 0,1 mol/l. 5.1.6 Starch solution, 1 %, i.e. 1 g in 100 ml water. 5.2 Reagents for the colorimetric method 5.2.1 Sodium dodecylsulfonate (detergent) solution, 0,1 %, 1 g in 1 000 ml water. 5.2.2 Solutio
34、n 1, 150 g ammonium acetate + 3 ml glacial acetic acid + 2 ml acetylacetone (pentane-2,4-dione, CAS 123-54-6) in 1 000 ml water. Prepare fresh daily and keep in a dark place. (It is sensitive to light.) 5.2.3 Solution 2, 150 g ammonium acetate + 3 ml glacial acetic acid in 1 000 ml water. 5.2.4 Dime
35、done solution, 5 g dimedone1)in 1 000 ml water. It is reported that dimedone cannot be readily dissolved in pure water. In such cases, dimedone can be dissolved in a small amount of ethanol and then made up to volume with water. 6 Apparatus Use usual laboratory equipment and, in particular, the foll
36、owing. 6.1 Volumetric flasks, of capacities 10 ml, 50 ml and 1 000 ml. 6.2 Erlenmeyer flasks, of capacities 25 ml, 100 ml and 250 ml. 6.3 Strainer with glass fibre filter, GF8 (or glass filter strainer G 3, diameter 70 mm to 100 mm). 6.4 Water bath, thermostatically controlled to 40 C 0,5 C, fitted
37、with a flask shaker or stirrer. 6.5 Thermometer, with 0,1 C graduations over the range 20 C to 50 C. 6.6 Analytical balance, weighing to an accuracy of 0,1 mg. 6.7 Spectrophotometer, with suitable cells capable of measuring absorbance at 412 nm. The recommended cell path length is 20 mm. 1) Dimedone
38、 (CAS 126-81-8) or methone is 5,5-dimethyl-1,3-cyclohexanedione. ISO 17226-2:2008(E) IULTCS/IUC 19-2:2008(E) ISO 2009 All rights reserved 37 Procedures 7.1 Procedure for the determination of formaldehyde in the stock solution 7.1.1 Preparation of the formaldehyde stock solution Pipette 5 ml of the f
39、ormaldehyde solution (5.1.1) into a 1 000 ml volumetric flask (6.1) which contains approximately 100 ml water. Then fill the flask with demineralized water up to the mark. This solution is the formaldehyde stock solution. 7.1.2 Determination Pipette 10 ml from this solution into a 250 ml Erlenmeyer
40、flask (6.2) and mix with 50 ml iodine solution (5.1.2). Add sodium hydroxide (5.1.3) until it turns yellow. Allow it to react for 15 min 1 min at 18 C to 26 C and then add 15 ml of sulfuric acid (5.1.4) while swirling. After adding 2 ml of starch solution (5.1.6), titrate the excess iodine with sodi
41、um thiosulfate (5.1.5) until the colour changes. Make three individual determinations. Titrate at least two blank solutions in the same manner. ()01 1 FAFA2VV cM= where FAis the concentration of the formaldehyde stock solution, in milligrams per 10 ml (mg/10 ml); V0is the titre of the thiosulfate so
42、lution for the blank solution, in millilitres (ml); V1is the titre of the thiosulfate solution for the sample solution, in millilitres (ml); MFAis the relative molecular mass of formaldehyde, 30,02 g/mol; c1is the concentration of the thiosulfate solution, in moles per litre (mol/l). 7.2 Procedure f
43、or the determination of formaldehyde in leather by the colorimetric method 7.2.1 Sampling and preparation of samples If possible, sample in accordance with ISO 2418. If sampling in accordance with ISO 2418 is not possible (e.g. leathers from finished products like shoes, garments), provide details a
44、bout sampling together with the test report. Grind leather in accordance with ISO 4044. If the result is to be presented on the basis of dry substance, then test an additional sample of the same leather in accordance with ISO 4684 so that the moisture content can be calculated. 7.2.2 Extraction Weig
45、h 2 g 0,1 g leather into a suitable vessel. Pipette 50 ml of the detergent solution (5.2.1) into a 100 ml Erlenmeyer flask (6.2) and warm it to 40 C. Transfer the pre-weighed leather quantitatively to the flask, then close it with a glass stopper (see next paragraph). Stir the content of the flask o
46、r shake smoothly at 40 C 0,5 C in a water bath (6.4) for 60 min 2 min. Immediately filter the warm extract solution by vacuum through a glass fibre filter (6.3) into a flask. Cool the filtrate, in a closed flask, down to room temperature (18 C to 26 C). Do not modify the leather/solution ratio. Extr
47、action and analysis should be performed within the same working day. BS EN ISO 17226-2:2008BS EN ISO 17226-2:2008ISO 17226-2:2008(E) IULTCS/IUC 19-2:2008(E) 4 ISO 2009 All rights reserved7.2.3 Reaction with acetylacetone 7.2.3.1 Pipette 5 ml of the filtrate obtained in 7.2.2 into a 25 ml Erlenmeyer
48、flask (6.2) and add 5 ml of the Solution 1 (5.2.2). Fit the Erlenmeyer flask with a glass stopper. Stir the solution for 30 min 1 min at a temperature of 40 C 1 C. After cooling (in the dark), measure the absorbance spectrophotometrically at 412 nm against a blank solution made from a mixture from 5
49、 ml detergent solution (5.2.1) + 5 ml Solution 1 (5.2.2). Register the absorbance obtained as Ep. For the purpose of determining the absorbance resulting from the initial colour of the filtrate obtained in 7.2.2, pipette 5 ml of the filtrate (7.2.2) into a 25 ml Erlenmeyer flask (6.2) and add 5 ml of Solution 2 (5.2.3). Thereafter, the same method is applied as with the sample. Register the absorbance obtained as Ee. 7.2.3.2 Take a smaller aliquot for leathers with a high content of formaldehyd
