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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 1541:1998 The Europ
2、ean Standard EN 1541:1998 has the status of a British Standard ICS 67.250; 85.060 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Paper and board intended to come into contact with foodstuffs Determination of formaldehyde in an aqueous extract Licensed Copy: sheffieldun sheffi
3、eldun, na, Fri Nov 17 08:44:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI This British Standard, having been prepared under the direction of the Consumer Products and Services Sector Board, was published under the authority of the Standards Board and comes into effect on 15 November 1998 BSI 1998 IS
4、BN 0 580 30152 4 BS EN 1541:1998 Amendments issued since publication Amd. No.DateText affected National foreword This British Standard is the English language version of EN 1541:1998. It supersedes BS EN 1541:1997 which is withdrawn. The UK participation in its preparation was entrusted by Technical
5、 Committee CW/47, Materials in contact with food, to Subcommittee CW/47/3, Paper and board in contact with foodstuffs, 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, an
6、d keep the UK interests informed; monitor related international and European developments and promulgate them in 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 Europ
7、ean publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled 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
8、 provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2
9、 to 5 and a back cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 08:44:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels
10、1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1541:1998 E EUROPEAN STANDARDEN 1541 NORME EUROPE ENNE EUROPA ISCHE NORM June 1998 ICS 67.250; 85.060Supersedes EN 1541:1996 Descriptors: Paper, paperboards, food products, food-
11、container contact, chemical analysis, determination of content, formaldehyde, aqueous extract, molecular absorption spectrophotometry English version Paper and board intended to come into contact with foodstuffs Determination of formaldehyde in an aqueous extract Papiers et cartons destine s a entre
12、r en contact avec des denre es alimentaires De termination du formalde hyde dans un extrait aqueux Papier und Pappe vorgesehen fu r den Kontakt mit Lebensmitteln Bestimmung von Formaldehyd in einem wa ssrigen Extrakt This European Standard was approved by CEN on 4 June 1998. CEN members are bound to
13、 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 Centra
14、l Secretariat 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 Central Secretariat has the same status as th
15、e 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 Kingdom. Licensed Copy: sheffieldun sheffieldun
16、, na, Fri Nov 17 08:44:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 2 EN 1541:1998 BSI 1998 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 supersedes EN 1541:1996. This
17、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 December 1998, and conflicting national standards shall be withdrawn at the latest by December 1998. With regard to EN 1541:1996 the following changes ha
18、ve been made: a) time data in 8.5 have been completed by deviation data; b) editorial updating. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark,
19、 Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword2 1Scope3 2Normative references3 3Definitions3 4Principle3 5Reagents3 6Apparatus4 7Preparation of sample4 8Procedure4 9Expre
20、ssion of results5 10Confirmation5 11Repeatability and reproducibility5 12Test report5 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 08:44:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 3 EN 1541:1998 BSI 1998 1 Scope This European Standard specifies the determination of formaldehyde in
21、aqueous extracts prepared from paper and board intended to come into contact with foodstuffs. The limit of determination is 0,01 mg/dm2 or 10 mg/kg paper or board. For contact at room temperature the cold water extract is applied. For paper and board materials intended for boiling and hot filtering
22、purposes, the hot water extract is applied. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated re
23、ferences, 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 references the latest edition of the publication referred to applies. EN 645, Paper and board intended to come into contact
24、with foodstuffs Preparation of a cold water extract. EN 647, Paper and board intended to come into contact with foodstuffs Preparation of a hot water extract. 3 Definitions For the purposes of this standard the following definitions apply. 3.1 cold water extract the water solution obtained as a resu
25、lt of cold extraction (see EN 645) 3.2 hot water extract the water solution obtained as a result of hot extraction (see EN 647) 4 Principle Formaldehyde reacts with pentane-2,4-dione (acetylacetone) in the presence of ammonium acetate to form 3,5-diacetyl-1,4-dihydrolutidine. The absorbance of the e
26、xtract is measured at a wavelength of 410 nm. NOTEThe extract should also be scanned by ultraviolet (UV) spectroscopy for confirmation where the level of formaldehyde exceeds specified limits (see clause 10). 5 Reagents All reagents shall be of analytical grade and the water shall be distilled or of
27、 equivalent purity. 5.1 Anhydrous ammonium acetate. 5.2 Acetic acid, 99 % (d = 1,05). 5.3 Pentane-2,4-dione, distilled under reduced pressure (3,33 kPa) at 25 8C. 5.4 Butan-1-ol. 5.5 Hydrochloric acid, 1 mol/l. 5.6 Sodium hydroxide solution, 1 mol/l. 5.7 Starch solution, freshly prepared, 2 g/l. 5.8
28、 Formaldehyde solution, 370 g/l to 400 g/l. 5.9 Standard iodine solution, 0,05 mol/l. 5.10 Standard sodium thiosulfate solution, 0,1 mol/l. 5.11 Pentane-2,4-dione reagent In a 100,0 ml volumetric flask dissolve: 15,0 g anhydrous ammonium acetate (5.1); 0,2 ml pentane-2,4-dione (5.3); 0,3 ml acetic a
29、cid (5.2); 25 ml of water. Make up to 100,0 ml with water (pH of final solution about 6,4). This reagent shall be freshly prepared. 5.12 Reagent (5.11), without pentane-2,4-dione. 5.13 Formaldehyde-standard: Stock solution Measure 5,0 ml formaldehyde solution (5.8) into a 1 000 ml volumetric flask a
30、nd make up to 1 000 ml with water. Just before use determine the strength of this solution as follows. Transfer 10,0 ml of the stock solution to a volumetric flask, add 25,0 ml of a standard iodine solution (5.9) and 10,0 ml of sodium hydroxide solution (5.6). Allow to stand for 5 min. Acidify with
31、11,0 ml of hydrochloric acid (5.5) and determine the excess iodine by titration with a standard sodium thiosulfate solution (5.10), using 0,1 ml of the starch solution (5.7) as indicator. NOTEAdd the starch solution when the solution to be titrated has become a pale straw colour. Theoretically, 1,0
32、ml of 0,05 mol/l iodine consumed is equivalent to 1,5 mg formaldehyde. 5.14 Formaldehyde-standard: Dilute solution Dilute an aliquot of the formaldehyde stock solution (5.13) to 20 times its volume with water, and then further dilute an aliquot of this second solution to 100 times its volume so that
33、 1,0 ml of the final solution contains about 1 mg of formaldehyde. Use pipettes and volumetric flasks. Calculate the actual formaldehyde content. This solution shall be freshly prepared. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 08:44:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 4
34、 EN 1541:1998 BSI 1998 1) Whatman is the trade name of a product supplied by Whatman. This information is given for the convenience of users of this standard and does not constitute an endorsement by CEN of the product named. Equivalent products may be used if they can be shown to lead to the same r
35、esults. 6 Apparatus 6.1 Ordinary laboratory apparatus. 6.2 Spectrometer, for use at the wavelength of 410 nm, with cells having 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
36、, capable of maintaining a temperature of (602) 8C. 6.5 Phase separation filter Phase separation filter capable of separating aqueous and solvent phases, i.e. retaining water and allowing the solvent to flow through. Chemical resistance: resistance to mineral acids to 4,0 mol/l and alkalis to 0,4 mo
37、l/l. NOTE 1Pre-washing with solvent is recommended. NOTE 2An example of a phase separation filter is Whatman 1 PS1). 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
38、(see EN 647). Two parallel extractions shall be carried out. The test should be performed not longer than 24 h after extraction. 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: 25,0 ml extract (V1) (8.1);
39、 5,0 ml pentane-2,4-dione reagent (5.11). 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: 25,0 ml extract (8.1); 5,0 ml reagent without pentane-2,4-dione (5.12). 8.4 Bl
40、ank test This is performed in order to construct the calibration curve. Into a 50 ml conical flask add: 25,0 ml water; 5,0 ml pentane-2,4-dione reagent (5.11). 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 (6.4) at (602)
41、 8C for 10 min10 s. Allow to cool for at least 2 min in a bath of iced water. Measure the absorbance of the reference solution (8.3) against distilled water. If the absorbence exceeds 0,2, a cleaning step using butan-1-ol is necessary. In this case, transfer the contents of the conical flasks into 1
42、00 ml separating funnels containing 10,0 ml of butan-1-ol (5.4). Rinse each conical flask with 3,0 ml to 5,0 ml of water. Shake the mixtures vigorously for (305) s. Allow the phases to separate. Filter the butan-1-ol phases into the measuring cells (6.2) through a phase separation filter (6.5). Brin
43、g the solutions into the measuring cells (6.2). Measure the absorbance at 410 nm of the sample solution (8.2) with the reference solution (8.3) in the reference cell (A1). Measure the absorbance of the blank test (8.4) with water in the reference cell, or with butan-1-ol (5.4) if the extraction with
44、 butanol has been performed (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 8C. 8.6 Calibration curve Into a 50 ml conical flask add: 1,0 ml of the formaldehyde diluted standard solution (5.14); 5,0 m
45、l of the pentane-2,4-dione reagent (5.11); make up with water to 30,0 ml. Continue as described in 8.5 and measure the absorbance with butan-1-ol (5.4) or water (see 8.5) in the reference cell. Repeat the procedure with 5,0 ml; 10,0 ml; 15,0 ml; 20,0 ml and 25,0 ml of the formaldehyde diluted standa
46、rd solution (5.14). Construct the calibration curve after subtraction of the blank test value (see 8.5) from each of the absorbances obtained. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 08:44:05 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 5 EN 1541:1998 BSI 1998 9 Expression of resul
47、ts 9.1 Subtract A2 from A1 and read off from the calibration curve (8.6) the amount C in mg of formaldehyde in the sample solution (8.2). 9.2 Calculate the formaldehyde content of the sample in mg/dm2or in mg/kg as follows: mg/dm2= C 3(1)33 V0 V1 b 100 1 G mg/kg = C 3(2)33 V0 V1 1 G 100 100 2 f wher
48、e: Cis the amount of formaldehyde read from the calibration graph, in mg; V0is the total volume of extract (250 ml), in ml; V1is the volume taken for the test (25,0 ml), in ml; bis the grammage, in g/m2; Gis the mass of the sample as taken, in g; fis the moisture content of the sample, in %. 10 Conf
49、irmation 10.1 Requirement for confirmation Where the level of formaldehyde in the water extract under test (clause 7) exceeds any specified limit, the determination shall be confirmed by scanning ultraviolet (UV) spectroscopy. 10.2 Standard spectrum Whilst preparing the formaldehyde derivative (8.5), scan the intermediate standard (10,0 ml standard from 8.6) from 300 nm to 500 nm. Record the position and absorbance value at the peak maximum and calculate the ratio of the measurements of the absorbance measured at 20
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