SIST EN 13805:2015

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Lebensmittel - Bestimmung von Elementspuren - DruckaufschlussProduits alimentaires - Dosage des éléments traces - Digestion sous pressionFoodstuffs - Determination of trace elements - Pressure digestion67.050Splošne preskusne in analizne metode za živilske proizvodeGeneral methods of tests and analysis for food productsICS:Ta slovenski standard je istoveten z:EN 13805:2014SIST EN 13805:2015en,fr,de01-januar-2015SIST EN 13805:2015SLOVENSKI
STANDARDSIST EN 13805:20021DGRPHãþD



SIST EN 13805:2015



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 13805
October 2014 ICS 67.050 Supersedes EN 13805:2002English Version
Foodstuffs - Determination of trace elements - Pressure digestion
Produits alimentaires - Dosage des éléments traces - Digestion sous pression
Lebensmittel - Bestimmung von Elementspuren - Druckaufschluss This European Standard was approved by CEN on 9 August 2014.
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 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-CENELEC 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, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
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EN 13805:2014 (E) 2 Contents Page Foreword .3 1 Scope .4 2 Normative references .4 3 Principle .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-assisted 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 time .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-heated autoclave .9 Annex A (normative)
Figures of apparatus . 10 Bibliography . 12
SIST EN 13805:2015



EN 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 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 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 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) 5.2.2, "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 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 Standard: 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, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 13805:2015



EN 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 atomic 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 normatively 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 chemical 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 measurement 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 digested 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 results 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 acid, 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 approximately (H2O2) = 1,11 g/ml. SIST EN 13805:2015



EN 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 stripping 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 accommodate 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 Pressure 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 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 Systems 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 using 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-measuring 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 elements, 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 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 105 Pa). Digestion vessels made of fluorinated plastics (PTFE and derivates) or of quartz glass are recommended. SIST EN 13805:2015



EN 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 Subboiling 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. Only 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 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 be
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