1、BRITISH STANDARDBS EN 15550:2007Animal feeding stuffs Determination of cadmium and lead by graphite furnace atomic absorption spectrometry (GF-AAS) after pressure digestionThe European Standard EN 15550:2007 has the status of a British StandardICS 65.120g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50
2、g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 15550:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2007 BSI 2007
3、ISBN 978 0 580 57504 4National forewordThis British Standard is the UK implementation of EN 15550:2007.The UK participation in its preparation was entrusted to Technical Committee AW/10, Animal feeding stuffs.A list of organizations represented on this committee can be obtained on request to its sec
4、retary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDAR
5、DNORME EUROPENNEEUROPISCHE NORMEN 15550October 2007ICS 65.120English VersionAnimal feeding stuffs - Determination of cadmium and lead bygraphite furnace atomic absorption spectrometry (GF-AAS) afterpressure digestionAliments des animaux - Dtermination de la teneur encadmium et en plomb par spectromt
6、rie dabsorptionatomique four graphite (GF-AAS) aprs digestion souspressionFuttermittel - Bestimmung von Cadmium und Blei mittelsGraphitrohrofen-Atomabsorptionsspektrometrie (GF-AAS)nach DruckaufschlussThis European Standard was approved by CEN on 26 August 2007.CEN members are bound to comply with t
7、he 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
8、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 vers
9、ions.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, Spai
10、n, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Membe
11、rs.Ref. No. EN 15550:2007: EEN 15550:2007 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Principle5 5 Reagents.5 6 Apparatus .6 7 Sampling.6 8 Preparation of the test sample .7 9 Procedure .7 10 Calculation and expression of the result 9 11 Precision.10
12、 12 Test report 11 Annex A (informative) Results of the interlaboratory tests.12 Annex B (informative) Notes on the detection technique, interferences and quantification, pressure digestion.14 Bibliography 16 EN 15550:2007 (E) 3 Foreword This document (EN 15550:2007) has been prepared by Technical C
13、ommittee CEN/TC 327 “Animal feeding stuffs - Methods of sampling and analysis”, the secretariat of which is held by NEN. 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 2008, and conflicting
14、 national standards shall be withdrawn at the latest by April 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 C
15、EN/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,
16、 Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 15550:2007 (E) 4 1 Scope This European Standard specifies a method for the determination of the elements cadmium and lead in animal feeding stuffs by graphite
17、 furnace atomic absorption spectrometry (GF-AAS) after pressure digestion. The method limit of quantification for each element is dependent on the sample matrix as well as the instrument. For cadmium a limit of quantification of 0,05 mg/kg should normally be obtained while for lead, a limit of quant
18、ification of 0,5 mg/kg should be obtained. 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 amen
19、dments) applies. EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696:1987) ISO 6498, Animal feeding stuffs Preparation of test samples 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 limit of detection (L
20、OD) smallest measured content from which it is possible to deduce the presence of the analyte with reasonable statistical certainty NOTE The limit of detection is numerically equal to three times the standard deviation of the mean of blank determinations (n 10, where n = number of measures) performe
21、d under reproducibility conditions. 3.2 limit of quantification (LOQ) lowest content of the analyte that can be measured with reasonable statistical certainty NOTE If both trueness and precision are constant over a concentration range around the limit of detection, then the limit of quantification i
22、s numerically equal to ten times the standard deviation of the mean of blank determinations (n 10, were n = number of measures) performed under reproducibility conditions. 3.3 feed additives substances that comply with the definition of feed additives given in the Regulation (EC) No 1831/2003 of the
23、 European Parliament and of the Council of 22 September 2003 on additives for use in animal nutrition 3.4 animal feeding stuffs substances that comply with the definition of animal feeding stuffs given in the Regulation (EC) No 178/2002 EN 15550:2007 (E) 5 4 Principle For the determination of the el
24、ements cadmium and lead, a test portion of the sample is digested under pressure. The concentration of the elements is determined by graphite furnace atomic absorption spectrometry (GF-AAS) using external calibration. The method detection limit for each element is dependent on the sample matrix as w
25、ell as the instrument, the type of atomizer and the use of chemical modifiers. A typical sample volume of 10 l to 20 l is used. WARNING Use of this European Standard can involve hazardous materials, operations and equipment. This standard does not purport to address all the safety problems associate
26、d with its use. It is the responsibility of the user of this European Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 5 Reagents 5.1 General Use only reagents of recognized analytical grade, and water conforming to
27、 grade 2 of EN ISO 3696. 5.2 Nitric Acid, concentrated, not less than 65 % (mass fraction), c(HNO3) = 14,4 mol/l, having a density of approximately (HNO3) = 1,42 g/ml. 5.3 Hydrogen peroxide, mass fraction not less than 30 %. 5.4 Element stock solutions Cd, Pb c = 1 000 mg/l The user should choose a
28、suitable stock solution. Both single-element stock solutions and multi-element stock solutions with adequate specifications stating the acid used and the preparation technique are commercially available. It is advisable to use certified stock solutions. Stock solutions should not be used after expir
29、ation dates. Element stock solutions with concentrations different from 1 000 mg/l may also be used. 5.5 Calibration solutions Prepare a range of standards including a blank calibration solution, which covers the linear range of the element to be determined by diluting the element stock solutions (5
30、.4). Appropriate matrix matching of the calibration solutions shall be performed (see Annex B), e.g. adjust the acid concentration of the standards to the acid concentration of the samples. Dilute to volume with water. 5.6 Matrix modifier (e.g. Palladium nitrate/magnesium nitrate modifier) Pd(NO3)2s
31、olution (Pd-nitrate solution) is commercially available (mass concentration 10 g/l). Dissolve 0,259 g of Mg(NO3)26H20 (Mg-nitrate solution) in 100 ml of water. Mix the Pd-nitrate solution with twice as much Mg-nitrate solution. 10 l of the mixed solution is equal to 15 g Pd and 10 g Mg(NO3)2. It is
32、advisable to use this solution for not longer than one week. EN 15550:2007 (E) 6 The combination of Pd and Mg(NO3) is regarded as a “universal” modifier that could be used for a lot of elements. Other matrix modifiers may be used as well, e.g. palladium nitrate modifier and ammonium dihydrogen phosp
33、hate modifier. 5.7 Purge and protective gas Argon, Ar purity not less than 99,99% by volume. 6 Apparatus Usual laboratory apparatus and, in particular, the following. 6.1 Laboratory grinder 6.1.1 Use laboratory grinders that are equipped so that samples cannot be contaminated. 6.1.2 Laboratory grind
34、er capable of grinding to a particle size of less than or equal to 1 mm, e.g. a knife mill or equivalent. 6.1.3 Laboratory grinder capable of grinding to a particle size of less than or equal to 0,1 mm, e.g. a ball mill or equivalent. 6.1.4 Mortar with pestle, free of contamination. 6.2 Analytical b
35、alance, capable of weighing with an accuracy of 1 mg. 6.3 Pressure digestion apparatus, commercially available. The apparatus shall be tested for safety pressure vessels made of acid-resistant materials and having holders for the sample of acid-resistant material with a low level of contamination. A
36、pparatus are available that uses a high-pressure incinerator with or without ambient autoclave pressure. Instead of polytetrafluoroethylene (PTFE) holders, it is better to use graduated quartz holders, perfluoro ethylene propylene (FEP) holders or perfluoro alkoxy (PFA) holders. Quartz is advisable
37、to be used for decomposition temperatures above 230 C. 6.4 Graphite furnace atomic absorption spectrometer, with background correction, e.g. Zeeman, supplied with auto sampler, an appropriate gas (5.7) supply and hollow cathode lamps or EDL-lamps for lead and cadmium. NOTE It is necessary to place a
38、n exhaust venting system over the furnace to remove any smoke and vapours that might be harmful. 6.5 Graphite tubes, pyrolytically coated and preferably with platforms. 6.6 Freeze drying equipment, capable of freeze-drying liquid animal feeding stuffs. 7 Sampling Sampling is not part of the method s
39、pecified in this International Standard. A recommended sampling method is given in EN ISO 6497. It is important that the laboratory receives a sample that is truly representative and has not been damaged or changed during transport or storage. EN 15550:2007 (E) 7 8 Preparation of the test sample 8.1
40、 General Prepare the test sample in accordance with ISO 6498. Grinding must be done in conditions such that the substance is not appreciably heated. Operation is to be repeated as many times as is necessary and it must be effected as quickly as possible in order to prevent any gain or loss of consti
41、tuents (water). Whole ground product is placed in a flask made of e.g. polypropylene, which can be stoppered and stored in such way to prevent any change in composition. Before any weighing is carried out for the analysis, the whole test sample must be thoroughly mixed for reasons of homogeneity. 8.
42、2 Animal feeding stuffs which can be ground as such Grind the laboratory sample (usually 500 g), using a grinder (6.1.2) or mortar (6.1.4), until a particle size of 1 mm or less has been reached. 8.3 Liquid animal feeding stuffs 8.3.1 General Liquid feeding stuffs shall be pre-dried according to the
43、 procedure described in 8.3.2 or freeze-dried according to the procedure described in 8.3.3. 8.3.2 Pre-drying Pre-dry the laboratory sample at 70 C 5 C during at least 16 h to reduce the moisture content. The mass of the sample before and after the pre-drying is to be determined using an analytical
44、balance (6.2). Grind the pre-dried sample in accordance with 8.2. 8.3.3 Freeze-drying Freeze-dry the laboratory sample following the instructions of the freeze-drying equipment (6.6). The mass of the sample before and after the freeze-drying is to be determined using an analytical balance (6.2). Gri
45、nd the freeze-dried sample in accordance with 8.2. 8.4 Mineral animal feeding stuffs Mineral compounds, except mineral products containing crystalline water, e.g. MgCl26H2O, shall be ground using a grinder (6.1.3) or mortar (6.1.4), until a particle size of 0,1 mm or less has been reached. Mineral p
46、roducts containing crystalline water should not be ground. 9 Procedure 9.1 Digestion 9.1.1 General Use pressure digestion. Proceed in accordance with 9.1.2. EN 15550:2007 (E) 8 9.1.2 Pressure digestion 9.1.2.1 General Match the initial sample mass to the capacity of the digestion vessel, strictly ob
47、serving the manufacturers instructions for safety reasons. Determine the necessary digestion temperature and digestion time (see EN 13805, see Annex B). 9.1.2.2 Example of microwave digestion When using 70 ml to 100 ml vessels, weigh about 0,5 g of the prepared test sample to the nearest 1 mg. Add 3
48、 ml of nitric acid (5.2) and 0,5 ml of hydrogen peroxide (5.3), seal the digestion vessel and the pressure holders in the correct manner. Leave to pre-digest outside the microwave for about 30 min. Apply low microwave energy at the beginning of the digestion and slowly raise the energy to the maximu
49、m power, e.g. start with 100 W, raise up to 600 W within 5 min, hold for 5 min, raise to 1 000 W, hold for 10 min, cool down for minimum 20 min to 25 min. Treat a blank in the same way. Dilute the digestion solution accordingly and proceed in accordance with 9.2. 9.1.2.3 Example of a high pressure digestion When using a 70 ml vessel, weigh about 0,5 g of the prepared test sample to the nearest 1 mg. Add 3 ml of nitric acid (5.2), seal the digestion vessel and the pressure vessel in the correct manner and heat from room temperature to
