1、September 2009DEUTSCHE NORM English price group 9No 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!$YaD“154623
2、3www.din.deDDIN EN ISO 17226-2Leather Chemical determination of formaldehyde content Corrigendum AC:2009)English version of DIN EN ISO 17226-2:2009-09Leder Chemische Bestimmung des Formaldehydgehalts Teil 2: Kolorimetrische Analyse (ISO 17226-2:2008) (enthlt Berichtigung AC:2009)Englische Fassung DI
3、N EN ISO 17226-2:2009-09SupersedesDIN EN ISO 17226-2:2008-08www.beuth.dePart 2: Method using colorimetric analysis (ISO 17226-2:2008) (includesDocument comprises 14 pagesDIN EN ISO 17226-2:2009-09 2 National foreword This standard has been prepared by Technical Committee CEN/TC 289 “Leather” (Secret
4、ariat: UNI, Italy). The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Technical Committee NA 062-05-52 AA Chemische Prfverfahren fr Leder. DIN EN ISO 17226 consists of the following parts, under the general title L
5、eather Chemical determination of formaldehyde content: Part 1: Method using high performance liquid chromatography Part 2: Method using colorimetric analysis The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 2418 DIN EN ISO 2418 ISO 3696
6、DIN ISO 3696 ISO 4044 DIN EN ISO 4044 ISO 4684 DIN EN ISO 4684 ISO 17226-1 DIN EN ISO 17226-1 Amendments This standard differs from DIN ISO/TS 17226:2004-01 as follows: a) The prestandard status has been changed to that of a full standard. b) The standard has been divided up into DIN EN ISO 17226-1
7、“Method using high performance liquid chromatography” and DIN EN ISO 17226-2 “Method using colorimetric analysis”. Compared with DIN EN ISO 17226-2:2008-08, the following correction has been made: c) In subclause 7.2.7, the equation has been corrected. Previous editions DIN ISO/TS 17226: 2004-01 DIN
8、 EN ISO 17226-2: 2008-08 DIN EN ISO 17226-2:2009-09 3 National Annex NA (informative) Bibliography DIN EN ISO 2418, Leather Chemical, physical and mechanical and fastness tests Sampling location DIN EN ISO 4044, Leather Chemical tests Preparation of chemical test samples DIN EN ISO 4684, Leather Che
9、mical tests Determination of volatile matter DIN EN ISO 17226-1, Leather Chemical determination of formaldehyde content Part 1: Method using high performance liquid chromatography DIN ISO 3696, Water for analytical laboratory use Specification and test methods DIN EN ISO 17226-2:2009-09 4 This page
10、is intentionally blank EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 17226-2 May 2008 +AC May 2009 ICS 59.140.30 English version Leather Chemical determination of formaldehyde content Part 2: Method using colorimetric analysis (ISO 17226-2:2008/Cor. 1:2009) Cuir Dosage chimique du formald
11、hyde Partie 2: Mthode par analyse colorimtrique (ISO 17226-2:2008/Cor. 1:2009) Leder Chemische Bestimmung des Formaldehyd-gehalts Teil 2: Kolorimetrische Analyse (ISO 17226-2:2008/Cor. 1:2009) EN ISO 17226-2:2008 was approved by CEN on 2008-04-26 and Corrigendum AC on 13 May 2009. CEN members are bo
12、und 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 to the
13、Management Centre or to any CEN member. The European Standards exist 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 Management Centre has the same status as t
14、he 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, Romania, Slova
15、kia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2009 CEN All rights of exploitation in any form and by any means reserved worldwide
16、 for CEN national Members. Ref. No. EN ISO 17226-2:2008+AC:2009 EContents Page Foreword .3 1 Scope4 2 Conformance .4 3 Normative references4 4 Principle .4 5 Reagents 5 6 Apparatus.5 7 Procedures.6 8 Expression of results9 9 Test report9 Annex A (informative) Precision: reliability of the colorimetr
17、ic method.10 2 DIN EN ISO 17226-2:2009-09 EN ISO 17226-2:2008+AC:2009 (E) 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 UNI in collaboration with Technical Committee ISO/TC IULTCS “International Union o
18、f 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 conflicting national standards shall be withdrawn at the latest by November 2008
19、. 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, the national standards organizati
20、ons 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, Norway, Poland, Portugal, Romania
21、, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice without any modification. 3 DIN EN ISO 17226-2:2009-09 EN ISO 17226-2:2008+AC:2009 (E) The text of ISO 17226-2:2008/Cor. 1:2009 has been approved by CEN as EN ISO 17226-2:2008+AC:2009 1 Scope This part of ISO
22、 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-formaldehyde and formaldehyde extracted through hydrolysis contained in a water extract from the
23、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 analytical methods should give similar trends but not necessarily the same absolute re
24、sult. 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 references, only the edition cited applies. For undated references, the latest edition of the
25、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 test methods ISO 4044, Leather Chemical tests Preparation of chemical test samples ISO
26、 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 sample is eluted with detergent solution at 40 C. The eluate is treated with acetylac
27、etone, 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 value for the test specimen is obtained from a calibration curve prepared under identical
28、 conditions. 4 DIN EN ISO 17226-2:2009-09 EN ISO 17226-2:2008+AC:2009 (E) 5 Reagents Use only reagents of recognized analytical grade, unless otherwise stated. The water shall be grade 3 in accordance with ISO 3696:1987. All solutions are aqueous solutions. 5.1 Reagents for the formaldehyde stock so
29、lution 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 hydroxide 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.
30、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 Solution 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
31、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 Dimedone 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
32、 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 following. 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 Strai
33、ner 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 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 acc
34、uracy 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 (CAS 126-81-8) or methone is 5,5-dimethyl-1,3-cyclohexanedione. 5 DIN EN ISO 17226-2:2009-09 EN ISO 17226-2:2008+AC:2009 (E) 7 Procedures 7.1
35、Procedure for the determination of formaldehyde in the stock solution 7.1.1 Preparation of the formaldehyde stock solution Pipette 5 ml of the formaldehyde 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
36、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 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
37、 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 sodium thiosulfate (5.1.5) until the colour changes. Make three individual determinations. Titrate at least two blank solutions in the same manner. ()01 1 FAFA2
38、VV cM= where FAis the concentration of the formaldehyde stock solution, in milligrams per 10 ml (mg/10 ml); V0is the titre of the thiosulfate solution for the blank solution, in millilitres (ml); V1is the titre of the thiosulfate solution for the sample solution, in millilitres (ml); MFAis the relat
39、ive molecular mass of formaldehyde, 30,02 g/mol; c1is the concentration of the thiosulfate solution, in moles per litre (mol/l). 7.2 Procedure for the determination of formaldehyde in leather by the colorimetric method 7.2.1 Sampling and preparation of samples If possible, sample in accordance with
40、ISO 2418. If sampling in accordance with ISO 2418 is not possible (e.g. leathers from finished products like shoes, garments), provide details about 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
41、 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 Weigh 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. Transf
42、er the pre-weighed leather quantitatively to the flask, then close it with a glass stopper (see next paragraph). Stir the content of the flask or 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 (
43、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. Extraction and analysis should be performed within the same working day. 6 DIN EN ISO 17226-2:2009-09 EN ISO 17226-2:2008+AC:2009 (E) 7.2.3 Reaction with acetyl
44、acetone 7.2.3.1 Pipette 5 ml of the filtrate obtained in 7.2.2 into a 25 ml Erlenmeyer 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 absorban
45、ce spectrophotometrically at 412 nm against a blank solution made from a mixture from 5 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,
46、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 formaldehyde ( 75 mg/kg).
47、 Make aliquots smaller than 5 ml up to 5 ml with water. EXAMPLE Formaldehyde content is approximately 500 mg/kg. Procedure: pipette 0,5 ml of the filtrate (7.2.2) into a 25 ml Erlenmeyer flask (6.2), add 4,5 ml water. Then follow the procedure as described in 7.2.3.1. 7.2.4 Checking reagents for abs
48、ence of formaldehyde Measure 5 ml detergent solution (5.2.1) + 5 ml Solution 1 (5.2.2) in relation to 5 ml of detergent solution (5.2.1) + 5 ml of water. The measured absorbance shall not be larger than 0,025 (measured in a 20 mm cell at 412 nm). 7.2.5 Testing other compounds which cause a colouring
49、 with acetylacetone Mix 5 ml of the filtrate obtained in 7.2.2 with 1 ml dimedone solution (5.2.4) and warm it up to 40 C 1 C for 10 min 1 min. Add 5 ml of the Solution 1 (5.2.2) and keep the mixture at 40 C 1 C for 30 min 1 min. Upon cooling down to room temperature, take a spectrophotometer absorbance measurement at 412 nm against a similar solution, which instead of the Solution 1 (5.2.2) contains 5 ml of Solution 2 (5.2.3). This absorbance shall be less than 0,0
