SIST EN 15517:2009
(Main)Foodstuffs - Determination of trace elements - Determination of inorganic arsenic in seaweed by hydride generation atomic absorption spectrometry (HGAAS) after acid extraction
Foodstuffs - Determination of trace elements - Determination of inorganic arsenic in seaweed by hydride generation atomic absorption spectrometry (HGAAS) after acid extraction
This document specifies a procedure for the determination of hydrochloric acid (gastric acid concentration) extractable inorganic arsenic in seaweed. Collaborative studies have been carried out (Annex A). The method is suitable for the determination of inorganic arsenic not less than 1 mg/kg and below 100 mg/kg on a dry weight basis. The amount of inorganic arsenic is considered to be that part determined by the procedure described in this document.
Lebensmittel - Bestimmung von Elementspuren - Bestimmung von anorganischem Arsen in Meeresalgen mit Atomabsorptionsspektrometrie-Hydridtechnik (HGAAS) nach Säureextraktion
Dieses Dokument legt ein Verfahren zur Bestimmung von mit Salzsäure (Magensäurekonzentration) extra¬hierbarem anorganischen Arsen in Meerespflanzen fest. Ringversuche sind durchgeführt worden (Anhang A). Das Verfahren ist anwendbar zur Bestimmung von anorganischem Arsen von mehr als 1 mg/kg und bis zu 100 mg/kg bezogen auf Trockengewicht. Die Menge von anorganischem Arsen wird betrachtet als der Anteil, der durch das in diesem Dokument beschriebene Verfahren bestimmt wird.
Produits alimentaires - Dosage des éléments traces - Dosage de l'arsenic inorganique dans les algues marines par spectrométrie d'absorption atomique par génération d'hydrures (SAAGH) après extraction acide
Le présent document spécifie un mode opératoire permettant de doser l’arsenic inorganique présent dans les
algues marines par extraction à l'acide chlorhydrique (concentration de l’acide gastrique). Des études
conjointes ont été réalisées (Annexe A) et ont montré que la méthode décrite dans le présent document était
appropriée pour doser l’arsenic inorganique à des concentrations comprises entre 1 mg/kg (inclus) et
100 mg/kg (exclus) en poids sec. Par concentration en arsenic inorganique on entend la quantité d’arsenic
déterminée au moyen du mode opératoire décrit dans le présent document.
Živila - Določevanje elementov v sledovih - Določevanje anorganskega arzena z metodo atomske absorpcijske spektrometrije - hidridna tehnika (HGAAS) po kislinski ekstrakciji
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Lebensmittel - Bestimmung von Elementspuren - Bestimmung von anorganischem Arsen in Meeresalgen mit Atomabsorptionsspektrometrie-Hydridtechnik (HGAAS) nach SäureextraktionProduits alimentaires - Dosage des éléments traces - Dosage de l'arsenic inorganique dans les algues marines par spectrométrie d'absorption atomique par génération d'hydrures (SAAGH) après extraction acideFoodstuffs - Determination of trace elements - Determination of inorganic arsenic in seaweed by hydride generation atomic absorption spectrometry (HGAAS) after acid extraction67.050Splošne preskusne in analizne metode za živilske proizvodeGeneral methods of tests and analysis for food productsICS:Ta slovenski standard je istoveten z:EN 15517:2008SIST EN 15517:2009en,fr,de01-april-2009SIST EN 15517:2009SLOVENSKI
STANDARD
SIST EN 15517:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15517March 2008ICS 67.050 English VersionFoodstuffs - Determination of trace elements - Determination ofinorganic arsenic in seaweed by hydride generation atomicabsorption spectrometry (HGAAS) after acid extractionProduits alimentaires - Dosage des éléments traces -Dosage de l'arsenic inorganique dans les algues marinespar spectrométrie d'absorption atomique par générationd'hydrures (SAAGH) après extraction acideLebensmittel - Bestimmung von Elementspuren -Bestimmung von anorganischem Arsen in Meeresalgen mitAtomabsorptionsspektrometrie-Hydridtechnik (HGAAS)nach SäureextraktionThis European Standard was approved by CEN on 7 February 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2008 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15517:2008: ESIST EN 15517:2009
EN 15517:2008 (E) 2 Contents Page Foreword.3 1 Scope.4 2 Normative references.4 3 Principle.4 4 Reagents.5 5 Apparatus and equipment.6 6 Procedure.7 7 Calculation.9 8 Precision.9 9 Test report.10 Annex A (informative)
Results of the inter-laboratory tests.11 Bibliography.14
SIST EN 15517:2009
EN 15517:2008 (E) 3 Foreword This document (EN 15517:2008) 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 September 2008, and conflicting national standards shall be withdrawn at the latest by September 2008. 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. 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, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 15517:2009
EN 15517:2008 (E) 4 1 Scope This document specifies a procedure for the determination of hydrochloric acid (gastric acid concentration) extractable inorganic arsenic in seaweed. Collaborative studies have been carried out (Annex A). The method is suitable for the determination of inorganic arsenic not less than 1 mg/kg and below 100 mg/kg on a dry weight basis. The amount of inorganic arsenic is considered to be that part determined by the procedure described in this document. 2 Normative references The following referenced documents are indispensable for the application of this document. 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 trace elements — Performance criteria, general considerations and sample preparation 3 Principle
Arsenic compounds are extracted from the sample by diluted hydrochloric acid (in accordance with EN 71-3 [5]) and the arsenic in the extract is determined by hydride generation AAS. In acidic media inorganic compounds of arsenic(III) and arsenic(V) as well as the monomethylarsonic acid (MMA) and dimethylarsinic (cacodylic) acid (DMA) form a volatile hydride with sodium borohydride. There is no reaction of the stable organic arsenic compounds like arsenosugar, arseno-betaine and arseno-choline under these conditions. The gaseous hydride is transferred into a heated measuring cell (cuvette) by means of a carrier gas stream and decomposed. The absorption at 193,7 nm (arsenic line) serves as a measure of arsenic concentration. The hydride signal sensitivity of DMA reaches generally low rates as compared to As(III). The contribution of MMA in the hydride signal can be neglected, since MMA occurs in seaweed only in small amounts. The hydride generation AAS in combination with this hydrochloric acid extraction may be used as nearly selective method of determination for inorganic arsenic. Generation of arsine from As(III) is much faster and gives greater sensitivity than generation from As(V) and is also less subject to interference. Arsenic(V) shall be reduced to arsenic(III) (pre-reduction) in order to avoid incorrect measurements. SIST EN 15517:2009
EN 15517:2008 (E) 5 4 Reagents 4.1 General The concentration of arsenic in the reagents and water used shall be low enough not to affect the results of the determination. 4.2 Hydrochloric acid, mass fraction w = 30 %, mass concentration ρ(HCl) = 1,15 g/ml. 4.3 Hydrochloric acid solution, substance concentration c
= (0,07 ± 0,005) mol/l. 4.4 Hydrochloric acid, approximately c = 2 mol/l. 4.5 Sodium borohydride, w ≥ 96 % 4.6 Sodium hydroxide, w ≥ 98 % 4.7 Sodium borohydride solution, e.g. substance concentration c = 2 g/l (example for using the flow injection procedure described under 6.2.1 (b)). Dissolve 2 g of sodium hydroxide pellets in water, add 2 g of sodium borohydride and dilute to 1 000 ml with water. A fresh solution shall be prepared daily and filtered before use. The concentration by mass of the sodium borohydride solution may vary with the system and the instructions of the relevant manufacturer shall therefore be observed. 4.8 Diluted hydrochloric acid, e.g. mass fraction w ≈ 3 % (carrier solution, only for use in the flow injection procedure). Dilute approximately 90 ml of hydrochloric acid (4.2) to 1 000 ml with water. The concentration by mass of the carrier solution may vary with the system and the instructions of the relevant manufacturer shall therefore be observed. 4.9 L-Ascorbic acid, w(C6H8O6) ≥ 99,7 % 4.10 Potassium iodide, w(KI) ≥ 99,5 % 4.11 Potassium iodide/ascorbic acid solution Dissolve 3 g of potassium iodide and 5 g of ascorbic acid in water and dilute to 100 ml. Prepare a fresh solution daily. The concentrations of the potassium iodide and ascorbic acid may vary slightly with the system and the instructions of the relevant manufacturer shall therefore be observed. 4.12 Diarsenic trioxide (As2O3), w(As2O3) ≥ 99,5 % 4.13 Arsenic stock solution, with an arsenic mass concentration of 1000 mg/l. If commercial stock solutions are not available, proceed as follows: dissolve 1,320 g of diarsenic trioxide SIST EN 15517:2009
EN 15517:2008 (E) 6 (4.12) in 25 ml of potassium hydroxide solution (ρ = 20 g/100 ml), neutralize with 20 % (mass fraction) sulfuric acid with phenolphthalein as indicator and dilute to 1 000 ml with 1 % (mass fraction) sulfuric acid. 4.14 Arsenic standard solutions Dilute the arsenic stock solution (4.13) in several steps. The arsenic standard solutions shall contain an adequate amount of hydrochloric acid, e.g. 2 ml of hydrochloric acid (4.2) per 100 ml. Example of a dilution series:
1000 mg/l →100/5 50 mg/l →50/5 5 mg/l →50/1 0,1 mg/l A standard solution of 5 mg/l arsenic in 0,6 % (mass fraction) hydrochloric acid is stable for at least one week. 4.15 Arsenic calibration solutions Prepare five calibration solutions in the required calibration range from the standard solution of 0,1 mg/l (4.14), ensuring that the concentrations of the calibration solutions are not outside the linear range of the calibration function and are also in the expected sample content range. The concentration of acid in the calibration solutions shall be equal to that in the sample solution. Example for the 1 µg/l to 10 µg/l range:
0,1 mg/l →100/1 1 µg/l
→100/3 3 µg/l
→100/5 5 µg/l
→100/8 8 µg/l
→100/10 10 µg/l The calibration solutions may also be prepared from the appropriately diluted standard solution in the measurement vessel itself by adding the reagents for the pre-reduction (see 6.1.3). Prepare fresh calibration solutions daily. The following procedure is recommended for the preparation of standard and calibration solutions: pour some water into the volumetric flask and add the requisite amount of acid. After cooling to room temperature, add the stock or standard solution using a pipette and dilute to the mark with water. 4.16 Zero member compensation solution, containing water and acid in a concentration equal to that in the sample solution. 5 Apparatus and equipment 5.1 General To minimise the contamination, all apparatus that come into direct contact with the sample and the solutions shall be carefully pre-treated according to EN 13804. SIST EN 15517:2009
EN 15517:2008 (E) 7 5.2 Atomic absorption spectrometer, with measurement recording system and accessories for the hydride generation method. 5.3 Element-specific lamp (hollow-cathode or electrodeless discharge lamp) for arsenic. 5.4 Centrifuge 5.5 Syringe filter (unit), pore size 0,45 µm, diameter 25 mm, resistant to hydrochloric acid (4.4). Membranes of polyester or nylon have been proven suitable.
5.6 Indicator paper 5.7 Device for thermostating, at approximately 37 °C. 5.8 Stirrer or shaking machine 6 Procedure 6.1 Sample preparation 6.1.1 General It is possible that extracted arsenic compounds are decomposed to inorganic arsenic, even when stored in a refrigerator. Therefore, determination by hydride generation AAS should be conducted as soon as possible, latest within one week. 6.1.2 Hydrochloric acid extraction In imitation of EN 71-3 the well homogenized sample is weighed (minimum weighed portion 0,2 g) i
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