1、BRITISH STANDARD Paper and board intended to come into contact with Determination of formaldehyde in an aqueous extract foodstuffs - The European Standard EN 1541:2001 has the status of a British Standard ICs 67.250; 85.060 BS EN 1541:2001 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COP
2、YRIGHT JAW I Amd. No. Date BS EN 1541:2001 Comments This British Standard, having been prepared under the direction of the Consumer Products and Services Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 June 2001 National foreword This Britis
3、h Standard is the official English language version of EN 1541:2001. It supersedes BS EN 1541:1998 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee CW/47, Materials in contact with food, to Subcommittee CW/47/3, Paper and board in contact with foodstuf
4、fs, which has the responsibility to: - - aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them i
5、n the UK. - A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section e
6、ntitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Comp
7、liance with a British Standard does not of itself confer immunity from legal obligations. a a Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 8, an inside back cover and a back cover. The BSI copyright date displayed in this document indic
8、ates when the document was last issued. O BSI 06-2001 ISBN O 580 37328 2 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 1541 April 2001 ICs 67.250; 85.060 Supersedes EN 1541 :1998 English version Paper and board intended to come into contact with foodstuffs - Determination of formaldehyde in a
9、n aqueous extract Papiers et cartons destins entrer en contact avec les denres alimentaires - Dtermination du formaldhyde dans un extrait aqueux Papier und Pappe vorgesehen fr den Kontakt mit Lebensmitteln - Bestimmung von Formaldehyd in einem wssrigen Extrakt This European Standard was approved by
10、CEN on 19 February 2001. CEN members are bound to comply with the CENKENELEC 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 standa
11、rds may be obtained on application to the 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
12、 Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kin
13、gdom. EUROPEAN COMMTEE FOR STANDARDIZATION COMITE EUROPBEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 0 2001 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1541:2001 E Pa
14、ge 2 EN 1541 : 2001 Contents Foreword . 3 1 Scope . 4 2 Normative References . 4 3 Terms and definitions . 4 4 5 6 7 8 9 10 11 Principle 4 Reagents . 4 Apparatus 5 Preparation of sample 5 Calculation and expression of results . 7 Repeatability and reproducibility . 8 Procedure 6 Confirmation . 7 12
15、Test report . . O 8 Page 3 EN 1541 : 2001 Foreword This European Standard has been prepared by Technical Committee CEN/TC 172 “Pulp, paper and board“, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identic
16、al text or by endorsement, at the latest by October 2001, and conflicting national standards shall be withdrawn at the latest by October 2001. This European Standard supersedes EN 1541 : 1998. With regard to EN 1541 : 1998-06 and EN 1541 : 1998/AC the following changes have been made: a) deletion of
17、 the Butan-1-01 step; b) correction of the formula 2 by incorporation of EN 1541 : 1998/AC; c) addition of more precise information-on the reproducibility, see 11.2; d) editorial updating. According to the CENKENELEC Internal Regulations, the national standards organizations of the following countri
18、es are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Noway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. 0 Page 4 EN 1541 : 2001 1 Scope O This European Standar
19、d specifies the determination of formaldehyde in aqueous extracts prepared from paper and board intended to come nt0 contact with foodstuffs. The limit of determination is 1 mgkg. This means that for a paper with a grammage of 100 urn2 the limit of determination will be 0,001 mg/drn2. For contact at
20、 room temperature the cold water extract is applied. For paper and board materials intended for boiling and hot filtering purposes the hot water extract is applied. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These nor
21、mative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated ref
22、erences the latest edition of the publication referred to applies (including amendments). EN 645 Paper and board intended to come into contact with foodstuffs - Preparation of a cold water extract Paper and board intended to come into contact with foodstuffs - Preparation of a hot water extract EN 6
23、47 3 Terms and definitions For the purposes of this Standard the following terms and definitions apply: 3.1 cold water extract: the water solution obtained as a result of cold extraction EN 6451. 3.2 hot water extract: the water solution obtained as a result of hot extraction EN 647. I 4 Principle F
24、ormaldehyde reacts with pentane-2,4-dione (acetylacetone) in the presence of ammonium acetate to form 3,5-diacetyl-l,4-dihydrolutidine. The absorbance of the extract is measured at a wavelength of 410 nm. NOTE The extract should also be scanned by ultraviolet (UV) spectroscopy for confirmation where
25、 the level of formaldehyde exceeds specified limits (see clause 1 O). 5 Reagents All reagents shall be of analytical grade and the water shall be distilled or of equivalent purity. 5.1 Anhydrous ammonium acetate 5.2 Acetic acid 99% (d = 1,05) 5.3 Pentane-2,Gdione 5.4 Hydrochloric acid, 1 mow 5.5 Sod
26、ium hydroxide solution, 1 moVI 5.6 Starch solution freshly prepared, 2 g/l 5.7 Formaldehyde solution, 370 g/l to 400 g/l 5.8 Standard iodine solution, 0,05 mol 5.9 Standard sodium thiosulphate solution, 0,l molh 5.1 O Pentane-2,4-dione reagent In a 100,O rnl volumetric flask dissolve: - 15,O g anhyd
27、rous ammonium acetate (see 5.1); - 0,2 rnl pentaneQ,Cdione (see 5.3); - 0,3 ml acetic acid (see 5.2); - 25 ml of water. Make up to 100,O rnl with water. This reagent shall be freshly prepared. 5.1 1 Reagent (see 5.10) without pentane-2,4-dione Page 5 EN 1541 : 2001 5.1 2 Formaldehyde-standard: Stock
28、 solution Measure 5,O ml formaldehyde solution (see 5.7) into a 1000 ml volumetric flask and make up to 1000 ml with water. Just before use determine the concentration of this solution as follows. Transfer 10,O ml of the stock solution into a conical flask, add 25,O ml of a standard iodine solution
29、(see 5.8) and 10,O ml of sodium hydroxide solution (see 5.5). Allow to stand for 5 min. Acidify with 11,0 ml of hydrochloric acid (see 5.4) and determine the excess iodine by titration with a standard sodium thiosulphate solution (see 5.9), using 0,l ml of the starch solution (see 5.6) as indicator.
30、 NOTE Add the starch solution when the solution being titrated has become a pale straw colour. Theoretically, 1 ,O ml of 0,05 moIA iodine consumed is equivalent to 1,5 mg formaldehyde. 5.1 3 Formaldehyde-standard: Dilute solution Dilute an aliquot of the formaldehyde stock solution (see 5.12) to 20
31、times its volume with water, and then further dilute an aliquot of this second solution to 1 O0 times its volume so that 1 ,O ml of the final solution contains about 0,001 mg of formaldehyde. Use pipettes and volumetric flasks. Calculate the actual formaldehyde content. This solution shall be freshl
32、y prepared. 0 6 Apparatus 6.1 Ordinary laboratory apparatus 6.2 Spectrometer for use at the wavelength of 410 nm, with cells of an optical path length of 10 mm. 6.3 Scanning ultraviolet (UV) spectrometer in the range of 300 nm to 500 nm (Only for the confirmation steps). 6.4 Thermostatic water-bath
33、capable of maintaining a temperature of (60 * 2)“ C. 7 Preparation of sample Sampling, sample preparation and extraction shall be carried out according to the methods for the preparation of cold water (see EN 645) or hot water extracts (see EN 647). Two parallel extractions shall be carried out. a T
34、he test shall be performed not longer than 24 h after extraction. Page 6 EN 1541 : 2001 8 Procedure 8.1 For each extract at least two parallel determinations shall be carried out. 8.2 Sample solution Into a 50 ml conical flask add - 25,O ml extract (V,) (see 8.1); - 5,O ml pentane-2,Cdione reagent (
35、see 5.10). 8.3 Reference solution Possible interference due to coloured substances in the aqueous extract is eliminated by the use of this reference solution. Into a 50 ml conical flask add - 25,O ml extract (see 8.1); - 5,O ml reagent without pentane-2,Cdione (see 5.1 1). 8.4 Blank test This is per
36、formed in order to construct the calibration curve. Into a 50 ml conical flask add - 25,O ml water; - 5,O ml pentane-2,Cdione reagent (see 5.10). 8.5 Determination Shake the solutions 8.2, 8.3 and 8.4 for about 15 s. Immerse the conical flasks in a thermostatic waterbath (see 6.4) at (60 f 2)“ for 1
37、0 min * 10 s. Allow to cool for at least 2 min in a bath of iced water. Bring the solutions into the measuring cells (see 6.2). Measure the absorbance at 410 nm of the sample solution (see 8.2) with the reference solution (see 8.3) in the reference cell (A,). Measure the absorbance of the blank test
38、 (see 8.4) with water in the reference cell (A2). The absorbance measurements shall be made between 35 min and 60 min from the time when the conical flasks were placed in the water bath at 60 OC. If the value of formaldehyde obtained exceeds the range covered by the calibration solutions, the measur
39、ement shall be repeated with a more dilute sample solution and using an equally diluted reference solution. 8.6 Calibration curve Into a 50 ml conical flask add: - 1 ,O ml of the formaldehyde diluted standard solution (see 5.1 3); - 5,O ml of the pentane-2,Cdione reagent (see 5.10); - make up with w
40、ater to 30,O ml. Continue as described in 8.5 and measure the absorbance with water (see 8.5) in the reference cell. Repeat the procedure with 5,O ml; 10,O ml; 15,O ml; 20,O ml and 25,O ml of the formaldehyde diluted standard solution (see 5.1 3). Construct the calibration curve after subtraction of
41、 the blank test value (see 8.5) from each of the absorbances obtained. a Page 7 EN 1541 : 2001 Wavelength pair nm 9 Calculation and expression of results 9.1 Subtract 4 from A, and read off from the calibration curve (see 8.6) the amount C in mg of formaldehyde in the sample solution (see 8.2). 9.2
42、Calculate the formaldehyde content of the sample (C, ) or (C, ) as follows: 0 Ratio Vo b 1 c, = cx - x - x - V, 100 G 370 / 410 390 / 410 430 / 410 450 / 410 vo 1 1 O0 c, = cx - x - x -x 1000 V, G 100 - f 0,520 f 0,02 0,843 f 0,Ol 0,802 f 0,Ol 0,386 f 0,02 where: C, amount of formaldehyde soluble of
43、 the sample in mg/drrf; amount of formaldehyde soluble of the sample in mgkg; ? amount of formaldehyde read from the calibration graph, in mg; Vo total volume of extract (250 mi), in ml; V, volume taken for the test (25,O mi), in ml; b grammage, in g/m2 G mass, in grams, of the sample taken under th
44、e same condition as grammage; f moisture content of the sample, in %. Report the result with two significant figures. 10 Confirmation 10.1 Requirement for confirmation Where the level of formaldehyde in the water extract under test (see clause 7) exceeds any specified limit, the determination shall
45、be confirmed by scanning ultraviolet (UV) spectroscopy (see 6.3). 10.2 Standard spectrum Whilst preparing the formaldehyde derivative (see 8.5), scan the intermediate standard (1 0,O ml standard from 8.6) from 300 nm to 500 nm. Record the position and absorbance value at the peak maximum and calcula
46、te the ratio of the measurements of the absorbance measured at 20 nm increments either side of the maximurn. The spectrum shall satisfy the following conditions: a) the maximum shall be in the range from 408 nm to 411 nm; b) the spectrum shall tend to zero absorbance, that is less than 0,02 absorban
47、ce units, below 320 nm. Examples of the absorbance ratios to be expected are listed in Table 1. Maximum absorbance : 410 nm Table 1 - Examples of absorbance ratios at corresponding wavelengths Page 8 EN 1541 : 2001 0,lO mgdm2 0,40 mgdm2 10.3 Sample spectrum Following the procedure of 10.2, record th
48、e spectrum of the relevant formaldehyde solution, determining the absorption maxima and the absorption ratios. These ratios shall agree with those found for the standard to within * 5%. If this criterion is satisfied, the level of formaldehyde found in equation (1) and/or (2) is confirmed. O 10% 5%
49、11 Repeatability and reproducibility 11.1 Repeatability From an interlaboratory test (n = 9) with both hot water and cold water extracts the test method described above gave repeatability (4 as shown in Table 2. Table 2 - Repeatability found in an interlaboratory test cold water extract cv Sample mean mgdm2 % 1 0,024 18 2 0,18 11 coefficient of variation (ri level hot water extract mean cv mg/dm2 % 0,097 10 0,27 20 11.2 Reproducibility From an interlaboratory test (n = 7) the test method described above gave a reproducibility, measured as the coefficient of variation (CV)
