1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58contact with foodstuffs Determination of cadmium and lead in an aqueous extractThe European Standar
2、d EN 12498:2005 has the status of a British StandardICS 67.250; 85.060Paper and board Paper and board intended to come into BRITISH STANDARDBS EN 12498:2005BS EN 12498:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 13 December 2005 BSI 1
3、3 December 2005ISBN 0 580 46955 7A list of organizations represented on this subcommittee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the
4、section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application
5、.Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesThis 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 notice displayed in this document indic
6、ates when the document was last issued.Amendments issued since publicationAmd. No. Date Comments aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor rel
7、ated international and European developments and promulgate them in the UK.National forewordThis British Standard is the official English language version of EN 12498:2005. It supersedes DD ENV 12498:1998 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee
8、 CW/47, Materials and articles in contact with foodstuffs, to Subcommittee CW/47/3, Paper and board in contact with foodstuffs, which has the responsibility to:EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 12498August 2005ICS 67.250; 85.060 Supersedes ENV 12498:1997 English VersionPaper and boar
9、d - Paper and board intended to come intocontact with foodstuffs - Determination of cadmium and lead inan aqueous extractPapier et carton - Papiers et cartons destins entrer encontact avec les denres alimentaires - Dtermination ducadmium et du plomb dans un extrait aqueuxPapier und Pappe - Papier un
10、d Pappe fr den Kontakt mitLebensmitteln - Bestimmung von Cadmium und Blei ineinem wssrigen ExtraktThis European Standard was approved by CEN on 27 June 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the s
11、tatus of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A
12、version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Esto
13、nia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITE
14、E FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12498:2005: EEN 12498:2005 (E) 2 Contents page Foreword 3 1 Scope .4 2 Normative references .4 3 Principle.4 4 Re
15、agents4 4.1 General 4 4.2 Nitric acid (HNO3), 65 % (d = 1,42)4 4.2.1 Nitric acid (4.2), diluted 1 : 1 (V/V) with water .4 4.2.2 Nitric acid (4.2), diluted to 1 % (V/V) with water4 4.3 Hydrochloric acid (HCl), 36 % (d = 1,19)4 4.4 Hydrochloric acid (HCl), 0,3 mol/l solution .4 4.5 Cadmium - stock sol
16、ution (Cd) = 1000 mg/l 5 4.6 Lead - stock solution (Pb) = 1000 mg/l 5 4.7 Matrix modifiers 5 4.7.1 Ammonium dihydrogen phosphate (NH4H2PO4) solution, 100,0 g/l 5 4.7.2 Palladium nitrate (Pd(NO3)2) solution, 21,7 g/l ( = 1 % Pd) .5 4.7.3 Magnesium nitrate (Mg(NO3)2) solution, 61,0 g/l ( = 1 % Mg) .5
17、4.8 Gases for atomic absorption spectrometry 5 5 Apparatus 5 5.1 General 5 5.2 General laboratory equipment .5 5.3 Volumetric flasks, 1000 ml .5 5.4 Analytical balance, accuracy 0,1 mg .5 5.5 Micropipettes from 5,0 l to 20,0 l with plastique tips (high density polyethylene/polypropylene bottles).6 5
18、.6 Atomic absorption spectrometer, with graphite tube furnace, and with background correction or inductively coupled plasma atomic emission spectrometer with background correction and radio frequency-generator6 6 Preparation of sample 6 7 Procedure 6 7.1 General 6 7.2 Preparation of reference soluti
19、ons6 7.3 Determination of cadmium and lead6 7.3.1 General 6 7.3.2 Calibration curve.6 7.3.3 Suggested spectrometer settings6 7.3.4 Determination of blank value .7 8 Expression of results7 9 Precision7 10 Test report .8 EN 12498:2005 (E) 3 Foreword This European Standard (EN 12498:2005) has been prep
20、ared 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 identical text or by endorsement, at the latest by February 2006, and conflicting national sta
21、ndards shall be withdrawn at the latest by February 2006. This European Standard supersedes ENV 12498:1997. With regard to ENV 12498:1997, the following changes have been made: a) introduction of the “Inductively coupled plasma emission spectroscopy (ICP)“; b) deletion of the chromium determination;
22、 c) addition of the clause “Precision“; d) 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, Cyprus, Czech Republic, Denmark, Estonia, Finland, France
23、, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 12498:2005 (E) 4 1 Scope This European Standard is one in a series of Standards for the determinatio
24、n of heavy metals in an aqueous extract of paper or board intended for contact with food. This European Standard specifies the test method for the determination of cadmium and lead in an aqueous extract. It is applicable to paper and paperboard with extractable metal contents exceeding 0,1 mg per kg
25、 for cadmium; 0,6 mg per kg for lead. NOTE 1 The above limits of determination are achieved by multiplying the actual limits existing today or proposed in Europe by 0,2. NOTE 2 Metal content levels below those given can be measured by this European Standard if very sensitive equipment is available a
26、nd if all other laboratory conditions fulfil the requirements for trace element analysis. 2 Normative references The following referenced documents are indispensable for the application of this European Standard. For dated references, only the edition cited applies. For undated references, the lates
27、t edition of the referenced document (including any amendments) applies. EN 645, Paper and board intended to come into contact 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 Principle An a
28、liquot portion from the stabilized cold water (see EN 645) or stabilized hot water extract (see EN 647) (see Clause 6) is analysed by atomic absorption spectrometry (AAS) using a graphite tube furnace or inductively coupled plasma emission spectroscopy (ICP). 4 Reagents 4.1 General All reagents and
29、the water used shall be suitable for trace element analysis. Store the solutions in high-density polyethylene/polypropylene bottles. 4.2 Nitric acid (HNO3), 65 % (d = 1,42) 4.2.1 Nitric acid (4.2), diluted 1 : 1 (V/V) with water 4.2.2 Nitric acid (4.2), diluted to 1 % (V/V) with water 4.3 Hydrochlor
30、ic acid (HCl), 36 % (d = 1,19) 4.4 Hydrochloric acid (HCl), 0,3 mol/l solution EN 12498:2005 (E) 5 4.5 Cadmium - stock solution (Cd) = 1000 mg/l Dissolve 1,142 g of cadmium oxide (CdO) in the minimum volume of nitric acid (4.2.1). Make up to 1000 ml with diluted nitric acid (4.2.2). 4.6 Lead - stock
31、 solution (Pb) = 1000 mg/l Dissolve 1,598 g of lead nitrate (Pb(NO3)2) in the minimum volume of nitric acid (4.2.1). Make up to 1000 ml with diluted nitric acid (4.2.2). 4.7 Matrix modifiers 4.7.1 Ammonium dihydrogen phosphate (NH4H2PO4) solution, 100,0 g/l 4.7.2 Palladium nitrate (Pd(NO3)2) solutio
32、n, 21,7 g/l ( = 1 % Pd) 4.7.3 Magnesium nitrate (Mg(NO3)2) solution, 61,0 g/l ( = 1 % Mg) NOTE Commercially available standard solutions and matrix modifiers can be used if preferred. 4.8 Gases for atomic absorption spectrometry Nitrogen as appropriate Argon 5 Apparatus 5.1 General All flasks, pipet
33、tes etc. have to be washed with nitric acid before use and stored in dilute nitric acid (4.2.2) until required. Rinse with demineralized water before use. 5.2 General laboratory equipment 5.3 Volumetric flasks, 1000 ml 5.4 Analytical balance, accuracy 0,1 mg EN 12498:2005 (E) 6 5.5 Micropipettes fro
34、m 5,0 l to 20,0 l with plastique tips (high density polyethylene/polypropylene bottles) 5.6 Atomic absorption spectrometer, with graphite tube furnace, and with background correction or inductively coupled plasma atomic emission spectrometer with background correction and radio frequency-generator 6
35、 Preparation of sample Prepare a cold water or a hot water extract from the paper or board using the test methods described in EN 645 or EN 647 respectively. Stabilize the extract by addition of nitric acid (4.2) in the ratio of 1,0 ml per 100,0 ml of sample. Mix the aqueous extract well and take an
36、 aliquot portion for analysis. Use the appropriate matrix modifier(s) (4.7) according to the particular instrument in use and the analytical matrix of the extract. 7 Procedure 7.1 General Detailed instructions depend on the form of the equipment used. Follow the instructions of the manufacturer of t
37、he equipment. Correct the background absorption by use of a suitable system. 7.2 Preparation of reference solutions Prepare the reference solutions daily by diluting the single element solutions with nitric acid (4.2.2). The concentration to be selected will depend on the instrument used and the exp
38、ected concentrations in the extract. For lead, a reference solution containing 10,0 g/l is usually appropriate. For cadmium, a reference solution containing 1,0 g/l is appropriate. Prepare a calibration blank using all the reagents except for the metal stock solutions. 7.3 Determination of cadmium a
39、nd lead 7.3.1 General Carry out two parallel extractions. From each extract at least two parallel determinations shall be carried out. Determine the concentration of the element by means of the calibration graph (7.3.2) or alternatively, by use of the method of standard addition. 7.3.2 Calibration c
40、urve The calibration curve shall contain at least 3 points and cover the total range of concentrations being measured. Calculate the concentration of the element from the measured absorption. 7.3.3 Suggested spectrometer settings Cadmium 228,8 nm Lead 217,0 nm or 283,3 nm (preferred) EN 12498:2005 (
41、E) 7 7.3.4 Determination of blank value Submit the water and reagents used for the extraction to the test procedure to provide a blank value to be deducted from the extract value. NOTE Although not deprecated, the extract can only be supplied to the laboratory, together with the water used for the e
42、xtraction. Without this, no blank can be determined and therefore not deducted from the extract value. If a partial blank is determined this should be reported. 8 Expression of results Calculate the results with a computer or graphically. Take the blank value into consideration in the evaluation. Ex
43、press the results in mg/kg or mg/dm of paper. Calculate the cadmium, lead content of the sample (Cmsee formula (1), Cssee formula (2) as follows: 1000110010010m=fGVCC (1) 1001100001000sbGVCC = (2) where: Cm amount of cadmium or lead soluble of the sample in mg/kg; Csamount of cadmium or lead soluble
44、 of the sample in mg/dm2; C concentration of cadmium or lead read from the calibration graph, in g/l; V0total volume of extract, in ml; b grammage, in g/m2; f moisture content of the sample, in %; G mass of the sample taken under the same condition as grammage, in g. NOTE 1 The extractable cadmium,
45、lead content of the original paper or board may be calculated if data are available. NOTE 2 Trace element determinations are sensitive to a number of sources of error. It is, therefore, recommended to check the performance of the system by running standard reference materials. Standard reference sol
46、utions are commercially available. Special attention should be paid to factors such as high blank levels caused by impure reagents or modifiers, contamination during handling of the solutions, adsorption on the walls of vessels, inadequate background correction or unmatched acid concentrations of sa
47、mple and calibration solutions. The detection limit should be established by measuring a sufficient number of blanks to allow calculation of the standard deviation of the blank. The detection limit is determined as three times this standard deviation. 9 Precision From an interlaboratory test (n = 8)
48、 with two samples of a water extract with a known amount of added cadmium and lead the test method described above gave the overall standard deviation as shown in Table 1. EN 12498:2005 (E) 8 Table 1 Mean value Overall standard deviation (s) Reference value (added cadmium/lead) Sample Cd g/l Pb g/l
49、Cd g/l Pb g/l Cd g/l Pb g/l 1 4,95 14,8 0,43 0,19 4,5 15 2 20,3 89,0 2,29 2,03 20 90 10 Test report The test report shall include the following information: a) reference to this European Standard; b) extraction method; c) type, origin and designation of sample; d) date of sampling; e) whether or not a blank value has been measured on the water used; f) date of receipt and date of analyses; g) test result; h) any departures from the specified procedure that may have affecte
