1、December 2014Translation by DIN-Sprachendienst.English price group 9No part of this translation 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
2、 67.050!%Ze“2275566www.din.deDDIN EN 13805Foodstuffs Determination of trace elements Pressure digestion;English version EN 13805:2014,English translation of DIN EN 13805:2014-12Lebensmittel Bestimmung von Elementspuren Druckaufschluss;Englische Fassung EN 13805:2014,Englische bersetzung von DIN EN 1
3、3805:2014-12Produits alimentaires Dosage des lments traces Digestion sous pression;Version anglaise EN 13805:2014,Traduction anglaise de DIN EN 13805:2014-12SupersedesDIN EN 13805:2002-06www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 1
4、4 pages11.14 DIN EN 13805:2014-12 2 A comma is used as the decimal marker. National foreword This document (EN 13805:2014) has been prepared by Technical Committee CEN/TC 275 “Food analysis Horizontal methods” (Secretariat: DIN, Germany). The responsible German body involved in its preparation was t
5、he DIN-Normenausschuss Lebensmittel und landwirtschaftliche Produkte (DIN Standards Committee Food and Agricultural Products), Working Committee NA 057-01-09 AA Elemente und ihre Verbindungen. Amendments This standard differs from DIN EN 13805:2002-06 as follows: a) some clauses have been restructur
6、ed; b) Subclause 5.2.2 “Pressure digestion apparatus with conventional heating” has been included; c) Subclause 5.2.3 “Pressure digestion apparatus with microwave-assisted heating” has been included; d) Subclause 5.2.4 “Pressure digestion autoclave with microwave-assisted heating” has been included;
7、 e) Subclause 6.3.2 “Acid addition” has been revised; f) Subclause 6.4 “Example of pressure digestions” has been completely revised and completed; g) the Bibliography has been added; h) the standard has been editorially revised. Previous editions DIN EN 13805: 2002-06 EN 13805October 2014 ICS 67.050
8、 Supersedes EN 13805:2002English Version Foodstuffs - Determination of trace elements - Pressure digestion Produits alimentaires - Dosage des lments traces - Digestion sous pression Lebensmittel - Bestimmung von Elementspuren - Druckaufschluss This European Standard was approved by CEN on 9 August 2
9、014. CEN members are bound 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
10、 on application to the CEN-CENELEC 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 CEN-CE
11、NELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, It
12、aly, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CEN All rights of exploitation in any form and by any means reser
13、ved worldwide for CEN national Members. Ref. No. EN 13805:2014 EEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGEN 13805:2014 (E) 2 Contents PageForeword 3 1 Scope 4 2 Normative references 4 3 Principle
14、4 4 Reagents .4 5 Apparatus and equipment 5 5.1 General 5 5.2 Pressure digestion apparatus 5 5.2.1 General 5 5.2.2 Pressure digestion apparatus with conventional heating .5 5.2.3 Pressure digestion apparatus with microwave-assisted heating .5 5.2.4 Pressure digestion autoclave with microwave-assiste
15、d heating .5 5.3 Ultrasonic bath with heating device 6 5.4 Subboiling distillation apparatus, 6 5.5 Stripping apparatus, 6 6 Procedure .6 6.1 General 6 6.2 Sample preparation .6 6.3 Pressure digestion conditions .6 6.3.1 Sample 6 6.3.2 Acid addition 7 6.3.3 Digestion temperature .7 6.3.4 Digestion t
16、ime 8 6.3.5 Cooling 8 6.3.6 Treatment of the digestion 8 6.3.7 Quality control of the analysis .8 6.4 Example of pressure digestions 8 6.4.1 Example of a high-pressure ashing digestion with conventional heating 8 6.4.2 Example of a microwave digestion 9 6.4.3 Example of a digestion in a microwave-he
17、ated autoclave 9 Annex A (normative) Figures of apparatus . 10 Bibliography . 12 DIN EN 13805:2014-12EN 13805:2014 (E) 3 Foreword This document (EN 13805:2014) has been prepared by Technical Committee CEN/TC 275 “Food analysis - Horizontal methods”, the secretariat of which is held by DIN. This Euro
18、pean Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2015 and conflicting national standards shall be withdrawn at the latest by April 2015. Attention is drawn to the possibility that some of the elements
19、 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. This document supersedes EN 13805:2002. The changes between this edition and the previous one are as follows: a) restructuring of some clauses; b) 5.
20、2.2, “Pressure digestion apparatus with conventional heating“ was added; c) 5.2.3, “Pressure digestion apparatus with microwave-assisted heating“ was added; d) 5.2.4, “Pressure digestion autoclave with microwave-assisted heating“ was added; e) 6.3.2, “Acid addition“ was revised” f) 6.4, “Example of
21、pressure digestions“ was completely revised and completed; g) bibliographic referenced were added; h) the whole document was editorially revised. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European St
22、andard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
23、Spain, Sweden, Switzerland, Turkey and the United Kingdom. DIN EN 13805:2014-12EN 13805:2014 (E) 4 1 Scope This European Standard specifies a method for the pressure digestion of foodstuffs intended for the determination of elements. This method has been collaboratively tested in combination with at
24、omic absorption (flame, electrothermal (ET), hydride, cold-vapour) techniques and ICP-MS. Other techniques such as e.g. ICP-OES, voltammetry or atomic fluorescence can be used in combination with this European Standard. 2 Normative references The following documents, in whole or in part, are normati
25、vely referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 13804, Foodstuffs - Determination of elements and their chemi
26、cal species - General considerations and specific requirements 3 Principle The method is a physicochemical pressure digestion method used to mineralize the sample material and to prepare a measurement solution containing elements to be determined. The method described here is applied when the measur
27、ement has been validated in combination with this digestion method and reference is made to this European Standard. This procedure will relate to the total element content depending on reagents and determination procedures used. The sample is homogenized avoiding contamination. Afterwards it is dige
28、sted with nitric acid (sometimes with addition of other acids), at high temperatures and pressure in a closed vessel, applying conventional or microwave-assisted heating 1, 2, 3. 4 Reagents The concentration of the trace elements in reagents and water used shall be low enough to not affect the resul
29、ts of the determination. In the case of insufficient purity, it is necessary to purify nitric acid and hydrochloric acid in a distillation apparatus (see 5.4 and Figure A.1). 4.1 Nitric acid, mass fraction w of not less than 65 % and density of approximately (HNO3) = 1,4 g/ml. 4.2 Diluted nitric aci
30、d, mix nitric acid (4.1) and water in a proportion of at least (1 + 9) parts by volume. 4.3 Hydrochloric acid, w not less than 30 % and approximately (HCl) = 1,15 g/ml. 4.4 Hydrofluoric acid, w not less than 40 % and approximately (HF) = 1,14 g/ml. 4.5 Hydrogen peroxide, w not less than 30 % and app
31、roximately (H2O2) = 1,11 g/ml. DIN EN 13805:2014-12EN 13805:2014 (E) 5 5 Apparatus and equipment 5.1 General To minimize contamination, carefully clean all those apparatus coming into contact with the sample by treating it with diluted nitric acid (4.2) and afterwards with water. In addition, a stri
32、pping apparatus (Figure A.2) can be used for cleaning vessels or bottles. 5.2 Pressure digestion apparatus 5.2.1 General Commercially available safety-tested pressure vessels made of acid-resistant materials and comprising inserts of acid-resistant, low-contamination materials are used to accommodat
33、e the sample material. The pressure vessels shall be able to withstand a temperature of at least 180 C as well as be stably operated at this temperature. Ensure safe operation during the whole digestion process by suitable safety devices (e.g. bursting discs, pressure shell, power control). 5.2.2 Pr
34、essure digestion apparatus with conventional heating Apparatus working with or without external autoclave pressure and designed for various working pressures should be used. Inserts of polytetrafluoroethylene (PTFE), quartz glass, perfluoroethylenepropylene (FEP) 4, 5 or perfluoroalkoxy (PFA) can be
35、 used. If digestion temperatures exceed 230 C, the use of quartz glass is advantageous. For the determination of mercury and other elements, which are adsorbed easily on rough surfaces (e.g. antimony), quartz glass is recommended. 5.2.3 Pressure digestion apparatus with microwave-assisted heating Sy
36、stems with microwave-assisted heating shall be equipped with a temperature-measuring device. The temperature of the digestion solution can be measured internally and/or externally 6. Reliable temperature measurement values are obtained, e.g. via sensors introduced into the pressure vessel. When usin
37、g an infrared sensor for measuring the vessel temperature, it shall be ensured through consultation with the manufacturer that the displayed temperature corresponds to the temperature of the solution in the pressure vessel. Do not use systems with microwave-assisted heating without a temperature-mea
38、suring device. Inserts made of fluorinated plastics such as PTFE, advanced PFA or perfluoropropylvinylether-modified PTFE (e.g. TFM) as well as quartz glass can be used. If digestion temperatures exceed 230 C the use of quartz glass is advantageous. For the determination of mercury and other element
39、s, which are adsorbed easily on rough surfaces (e.g. antimony), quartz glass is recommended. 5.2.4 Pressure digestion autoclave with microwave-assisted heating Alternatively to the apparatus described under 5.2.2 and 5.2.3, systems with a microwave heated autoclave can be used. The microwave energy
40、is coupled into the absorption liquid and thus the digestion vessels are heated. The digestion vessels are sealed with an autoclave filling pressure of at least 40 bar (= 40 x 105Pa). Digestion vessels made of fluorinated plastics (PTFE and derivates) or of quartz glass are recommended. DIN EN 13805
41、:2014-12EN 13805:2014 (E) 6 If digestion temperatures exceed 230 C, the use of quartz glass is advantageous. For the determination of mercury and other elements, which are adsorbed easily on rough surfaces (e.g. antimony), quartz glass is recommended. 5.3 Ultrasonic bath with heating device 5.4 Subb
42、oiling distillation apparatus, made of quartz glass or a similar material of high-purity fluoropolymers, according to Figure A.1, for distilling acids at temperatures below their boiling point. 5.5 Stripping apparatus, according to Figure A.2, for cleaning vessels or bottles with hot acid vapour. On
43、ly vessels or bottles made of fluorinated plastics (PTFE and its derivates), of quartz glass or glass are stable during the stripping procedure. 6 Procedure 6.1 General WARNING The application of this standard can involve the use of dangerous substances, operations and equipment. This standard does
44、not purport, however, to address all the safety problems associated with its use. It is the responsibility of the user of this standard to establish the appropriate safety and health measures, which comply with applicable and current regulations. During each step of the method, contamination shall b
45、e as low as possible. It shall be borne in mind that the digestion of carbon-rich materials (e.g. cellulose, carbohydrates, fats, oils) can result in explosions. Alcohol shall be evaporated since its contact with concentrated nitric acid results in delayed violent reactions. Perchloric acid shall no
46、t be used for pressure digestion. Before the pressure digestion apparatus is used, read operating manual and safety instructions carefully. Particular attention shall be paid to the risk to the laboratory staff posed by nitrogen oxides. 6.2 Sample preparation Prepare the samples using normal househo
47、ld practices. Avoid as far as possible any contamination with the elements to be determined (e.g. when determining chromium and nickel, no stainless steel equipment shall be used for the sample preparation), see EN 13804. The sample preparation shall ensure homogeneous starting material for the test
48、 portion. 6.3 Pressure digestion conditions 6.3.1 Sample Adapt the sample weight to the capacity of the digestion vessel and the maximum permissible pressure increase; in doing so, do not deviate from the manufacturers information for safety reasons. The maximum sample weight depends on the samples
49、carbon content and water content. In the case of carbon-rich samples, such as fats and carbohydrate rich foodstuffs, a maximum of 200 mg (to the nearest milligram) of fresh mass can as a rule be digested 5. If the carbon content is lower, the mass of the sample may be increased up to 3 g of fresh mass or 4 ml of liquid. Depending on the volume of the digestion vessels, other sample weights may be used; but the ratio of sample mass to acid volume (6.3.2), however, sh
