1、August 2008DEUTSCHE 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!$QNU“1464350ww
2、w.din.deDDIN EN ISO 17226-1Leather Chemical determination of formaldehyde content Part 1: Method using high performance liquid chromatography(ISO 17226-1:2008)English version of DIN EN ISO 17226-1:2008-08Leder Chemische Bestimmung des Formaldehydgehalts Teil 1: Hochleistungs-Flssigkeitschromatograph
3、ie (ISO 17226-1:2008)Englische Fassung DIN EN ISO 17226-1:2008-0817226-2:2008-08,supersedesDIN ISO/TS 17226:2004-01www.beuth.deTogether with DIN EN ISODocument comprises 11 pagesDIN EN ISO 17226-1:2008-08 2 National foreword This standard has been prepared by Technical Committee CEN/TC 289 “Leather”
4、 (Secretariat: 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
5、 title Leather 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 I
6、SO 3696 DIN ISO 3696 ISO 4044 DIN EN ISO 4044 ISO 4684 DIN EN ISO 4684 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 “Method using high perf
7、ormance liquid chromatography” and DIN EN ISO 17226-2 “Method using colorimetric analysis”. Previous editions DIN ISO/TS 17226: 2004-01 National Annex NA (informative) Bibliography DIN EN ISO 2418, Leather Chemical, physical and mechanical and fastness tests Sampling location DIN EN ISO 4044, Leathe
8、r 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 STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 17226-1 May 2008 ICS 59.140.30 Engl
9、ish Version Leather - Chemical determination of formaldehyde content - Part 1: Method using high performance liquid chromatography (ISO 17226-1:2008) Cuir - Dosage chimique du formaldhyde - Partie 1: Mthode par chromatographie en phase liquide haute performance (ISO 17226-1:2008) Leder - Chemische B
10、estimmung des Formaldehydgehalts -Teil 1: Hochleistungs-Flssigkeitschromatographie (ISO 17226-1:2008) This European Standard was approved by CEN on 26 April 2008. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standar
11、d 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 CEN Management Centre or to any CEN member. This European Standard exists in three official versions (English, French,
12、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 same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Cze
13、ch 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 United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EURO
14、PEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 17226-1:2008: E2 Contents Page DIN EN ISO 17226-1:2008-08 EN ISO 17
15、226-1:2008 (E) Foreword3 1 Scope 4 2 Conformance4 3 Normative references 4 4 Principle4 5 Reagents.5 6 Apparatus .5 7 Procedures .6 8 Expression of results 8 9 Test report 8 Annex A (informative) Precision: reliability of the chromatographic HPLC method .9 3 Foreword This document (EN ISO 17226-1:20
16、08) 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 of Leather Technologists and Chemists Societies“. This European Standard shall be given the status of a national sta
17、ndard, 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. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rig
18、hts. 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 organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, C
19、zech 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 17226-1:2008 (E) DIN EN ISO 17226-1
20、:2008-08 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 high performance liquid chromatography (HPLC). It is selective and not sensitive to coloured extracts. The formaldehyde content is taken to be the q
21、uantity of free-formaldehyde and formaldehyde extracted through hydrolysis contained in a water extract from the leather under standard conditions. 2 Conformance When compared with ISO 17226-2, the two analytical methods should give similar trends but not necessarily the same absolute result. Theref
22、ore, in the case of dispute, this method (ISO 17226-1) shall be used in preference to ISO 17226-2. 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 lates
23、t 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 test methods ISO 4044, Leather Chemical tests Preparation of chemical
24、 test samples ISO 4684, Leather Chemical tests Determination of volatile matter 4 Principle The process is selective. Formaldehyde is separated and quantified as a derivative from other aldehydes and ketones by liquid chromatography. Detected is the free-formaldehyde and formaldehyde which is hydrol
25、ysed during extraction to yield free-formaldehyde. The sample is eluted with detergent solution at 40 C. The eluate is mixed with 2,4-dinitrophenylhydrazine, whereby aldehydes and ketones react to give the respective hydrazones. These are separated by means of a reversed-phase HPLC method, detected
26、at 360 nm and quantified. 4 DIN EN ISO 17226-1:2008-08 EN ISO 17226-1:2008 (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 sto
27、ck 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 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 %
28、, i.e. 1 g in 100 ml water. 5.2 Reagents for the HPLC method 5.2.1 Sodium dodecylsulfonate (detergent) solution, 0,1 %, 1 g in 1 000 ml water. 5.2.2 Dinitrophenylhydrazine (DNPH) solution, consisting of 0,3 g DNPH (2,4-dinitrophenylhydrazine) dissolved in 100 ml concentrated o-phosphoric acid (85 %
29、mass fraction). (DNPH recrystallized from 25 % mass fraction, acetonitrile in water) 5.2.3 Acetonitrile. 6 Apparatus Use usual laboratory equipment and, in particular, the following. 6.1 Volumetric flasks, of capacities 10 ml, 500 ml and 1 000 ml. 6.2 Erlenmeyer flasks, of capacities 100 ml and 250
30、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 with a flask shaker or stirrer. 6.5 Thermometer, with 0,1 C graduations over the range 20 C to 50 C. 6.6 HPLC system with UV detec
31、tion, 360 nm. 6.7 Membrane filter, polyamide, 0,45 m. 6.8 Analytical balance, weighing to an accuracy of 0,1 mg. 5 EN ISO 17226-1:2008 (E) DIN EN ISO 17226-1:2008-08 7 Procedures 7.1 Procedure for the determination of formaldehyde in the stock solution 7.1.1 Preparation of the formaldehyde stock sol
32、ution 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 and 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 solu
33、tion into a 250 ml Erlenmeyer flask (6.2) and mix with the 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), t
34、itrate 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 FAFA2VV cM= where FAis the concentration of the formaldehyde stock solution, in milligrams per 10 ml (mg/10 ml); V0
35、is 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 relative molecular mass of formaldehyde, 30,02 g/mol; c1is the concentration of the thiosulfate solution, in moles
36、per litre (mol/l). 7.2 Procedure for the determination of formaldehyde in leather by the HPLC 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, ga
37、rments), provide details about sampling together with the test report. Grind the leather in accordance with ISO 4044. If the result is to be presented on the basis of dry substance, then test a further sample of the same leather in accordance with ISO 4684 so that the moisture content can be calcula
38、ted. 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. Transfer the pre-weighed leather quantitatively to the flask, then close it with a glass stopper (see next paragraph). Stir
39、the content of the flask or shake it 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
40、 leather/solution ratio. Extraction and analysis should be performed within the same working day. 6 DIN EN ISO 17226-1:2008-08 EN ISO 17226-1:2008 (E) 7.2.3 Reaction with DNPH Pipette 4,0 ml of acetonitrile (5.2.3), a 5,0 ml aliquot of the filtered eluate (7.2.2) and 0,5 ml of DNPH solution (5.2.2)
41、into a 10 ml volumetric flask (6.1). Fill the volumetric flask with demineralized water up to the mark and shake it briefly by hand to mix the components. Allow it to stand at least 60 min, but not more than a maximum of 180 min. After filtering through a membrane filter (6.7), analyse the sample us
42、ing HPLC. If the concentration is out of the calibration range, take smaller aliquots. 7.2.4 HPLC conditions (recommendations) These conditions are only recommendations. The method used should be verified using the recovery rate determination (7.2.7) and the results observed should be in the range l
43、isted in Table A.1. Flow rate: 1,0 ml/min Mobile phase: acetonitrile/water, 60:40 Separation column: C18 reversed phase column with precolumn (1 cm, RP18) UV detection wavelength: 360 nm Injection volume: 20 l NOTE A Merck 100, CH 18,2 (highly coated, 12 % C) column is an example of a suitable separ
44、ation column which is commercially available.1)7.2.5 Calibration of HPLC Pipette 0,5 ml of the formaldehyde stock solution obtained in 7.1.1, with an exactly known formaldehyde content, into a 500 ml volumetric flask (6.1), pre-filled with approximately 100 ml water. Mix together and fill to the mar
45、k with water, and mix again. This solution is the standard solution for calibration purposes, i.e. the standard solution is approximately 2 g formaldehyde/ml. In each of six 10 ml volumetric flasks (6.1), add 4 ml acetonitrile (5.2.3), then add a concentration series of 0,5 ml; 1,0 ml; 2,0 ml; 3,0 m
46、l; 4,0 ml; 5,0 ml, respectively, of the standard solution. Immediately upon addition of the formaldehyde solution (5.1.1), mix each flask and add 0,5 ml DNPH solution (5.2.2). Fill the flasks up to the mark with demineralized water and mix. After at least 60 min and not more than 180 min, analyse th
47、e samples using HPLC after filtration through a membrane filter (6.7). Effect the calibration through plotting a graph of the formaldehyde derivative peak area versus the concentration in micrograms per 10 ml. 7.2.6 Calculation of the formaldehyde content in leather samples SFFwm = where wFis the co
48、ncentration of formaldehyde in the sample in milligrams per kilogram (mg/kg) rounded to 0,01 mg/kg; Sis the concentration of formaldehyde obtained from the calibration graph in micrograms per 10 ml (g/10 ml); 1) A Merck 100, CH 18,2 column is an example of a suitable product available commercially.
49、This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of this product. 7 EN ISO 17226-1:2008 (E) DIN EN ISO 17226-1:2008-08 F is the dilution factor in millilitres (ml); m is the mass of leather weighed in grams (g). 7.2.7 Spiking Determination of recovery rate Pre-fill 4 ml acetonitrile (5.2.3) into a 10 ml volumetric flask (6.1) and add an aliquot of 2,5 ml of the filtrate, obtained as described in 7.2.2. Then add an accurately dete
