DIN EN 16279-2012 Animal feeding stuffs - Determination of fluoride content after hydrochloric acid treatment by ion-sensitive electrode method (ISE) German version EN 16279 2012《动.pdf

1、September 2012 Translation by DIN-Sprachendienst.English price group 11No 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).

2、ICS 65.120!$Vh“1915169www.din.deDDIN EN 16279Animal feeding stuffs Determination of fluoride content after hydrochloric acid treatment byion-sensitive electrode method (ISE);English version EN 16279:2012,English translation of DIN EN 16279:2012-09Futtermittel Bestimmung des Fluoridgehaltes nach Salz

3、sure-Behandlung mit ionensensitiverElektrode (ISE);Englische Fassung EN 16279:2012,Englische bersetzung von DIN EN 16279:2012-09Aliments des animaux Dtermination de la teneur en fluorure, aprs traitement lacide chlorhydrique, selon lamthode utilisant une lectrode slective dions (ISE);Version anglais

4、e EN 16279:2012,Traduction anglaise de DIN EN 16279:2012-09www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 20 pages 08.12 DIN EN 16279:2012-09 2 A comma is used as the decimal marker. National foreword This standard has been prepared by

5、 Technical Committee CEN/TC 327 “Animal feeding stuffs Methods of sampling and analysis” (Secretariat: NEN, Netherlands). The responsible German body involved in its preparation was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Food and Agricultural Products Standards Committee)

6、, Working Committee NA 057-03-03 AA Futtermittel. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). The International Standards referred to in this document have bee

7、n published as the corresponding DIN EN or DIN EN ISO Standards with the same number, except for those below, which correspond as follows: EN ISO 3696 DIN ISO 3696 ISO 5725-1 DIN ISO 5725-1 National Annex NA (informative) Bibliography DIN ISO 3696, Water for analytical laboratory use Specification a

8、nd test methods DIN ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16279 July 2012 ICS 65.120 English Version Animal feeding stuffs - Determination of fluoride content af

9、ter hydrochloric acid treatment by ion-sensitive electrode method (ISE) Aliments des animaux - Dtermination de la teneur en fluorure, aprs traitement lacide chlorhydrique, selon la mthode utilisant une lectrode slective dions (ISE) Futtermittel - Bestimmung des Fluoridgehaltes nach Salzsure-Behandlu

10、ng mit ionensensitiver Elektrode (ISE)This European Standard was approved by CEN on 17 May 2012. 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-

11、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 translati

12、on 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, F

13、ormer 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. EUROPEAN COMMITTEE FOR STANDARDIZATION COM

14、IT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16279:2012: EEN 16279:2012 (E) 2 Contents Page Foreword 3Introduct

15、ion .41 Scope 52 Normative references 53 Principle 54 Reagents .65 Apparatus .76 Sampling .77 Preparation of test sample 78 Procedure .89 Calculation and expression of results 1010 Precision 1211 Test report . 13Annex A (informative) Results of the interlaboratory study 14Annex B (informative) Flowc

16、hart Determination of fluoride content after hydrochloric acid treatment by ISE method . 15Annex C (informative) Interpolation reading . 16Bibliography . 18DIN EN 16279:2012-09 EN 16279:2012 (E) 3 Foreword This document (EN 16279:2012) has been prepared by Technical Committee CEN/TC 327 “Animal Feed

17、ing 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 January 2013, and conflicting national standards shall be wit

18、hdrawn at the latest by January 2013. 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 has been prepared under a mandate

19、given to CEN by the European Commission and the European Free Trade Association. 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 Republ

20、ic, 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. DIN EN

21、 16279:2012-09 EN 16279:2012 (E) 4 Introduction Fluorine (F) is one of the most abundant elements in the environment. Animals are exposed to the ionic form of the element, fluoride (F-), which may be present in feeding stuffs. The toxicity of fluoride has already been established by EFSA 6; and its

22、availability greatly depends on the solubility of fluoride compounds. In particular, fluoride compounds with low solubility are poorly absorbed while fluoride ions released from readily soluble compounds are almost completely absorbed from the gastrointestinal tract by passive diffusion in monogastr

23、ic species. The extraction procedure of this method involves a mild acid treatment with hydrochloric acid solution of 1 mol/l which should reflect the gastric hydrochloric acid concentration of 0,1 mol/l 0,3 mol/l. DIN EN 16279:2012-09 EN 16279:2012 (E) 5 1 Scope This European Standard specifies an

24、Ion-Selective Electrode method (ISE) after hydrochloric acid treatment for the determination of fluoride from animal feeding stuffs. The content of fluoride (F-) corresponds to that of fluorine (F) specified in Commission Regulation (EU) 574/20113. This European Standard is strictly based on several

25、 conventions such as those contained in the following example: EXAMPLE 0,5 g test portion for extraction of fluoride from animal feeds by means of an acid treatment with 20 ml of 1 mol/l hydrochloric acid solution at ambient temperature (20 C to 25 C) for 20 min. The pH is controlled and adjusted to

26、 5,5 in the buffered test solution before determination of fluoride by ISE using standard addition technique. The method was successfully tested in an interlaboratory study in concentrations between 100 mg/kg up to 500 mg/kg. If this method is followed strictly, then theoretically all concentrations

27、 from 40 mg/kg up to 4 000 mg/kg can be analysed within the linear calibration function. Only for concentrations lower than 40 mg/kg is the use of an interpolation technique required instead of standard addition Annex C. The quantification limit for fluoride using the conventions of the method inclu

28、ding the standard addition technique is 40 mg/kg or lower than 2,5 mg/kg when using interpolation Annex C. 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 editio

29、n cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 3696, Water for analytical laboratory use Specification and test methods EN ISO 6498, Animal feeding stuffs Guidelines for sample preparation 3 Principle For the determin

30、ation of fluoride, a test portion of 0,5 g of the sample is treated with 20 ml of 1 mol/l hydrochloric acid solution for 20 min at ambient temperature (20 C to 25 C). The amount of fluoride extracted from the sample is determined by means of a fluoride selective electrode. NOTE This ISE method is ba

31、sed upon a potentiometric technique. This means that it is based upon the measurement of a concentration of an analyte present in solution, by means of an ion selective electrode. This electrode has a linear response within a working range of analyte concentrations, which is provided by the calibrat

32、ion curve. Thus, in general, the operator should take an adequate amount of sample to ensure that the final concentration of the analyte is within this working range given by the calibration step. To ensure satisfactory reproducibility of the method however, this extraction procedure as a convention

33、 method fixes the ratio of the amount of the test portion to the volume of the extraction solvent for all kind of feeds. WARNING The use of this European Standard can involve hazardous materials, operations and equipment. This standard does not purport to address all the safety problems associated w

34、ith 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. DIN EN 16279:2012-09 EN 16279:2012 (E) 6 4 Reagents Use only reagents of recognised analytical grad

35、e, unless otherwise specified. 4.1 Water, complying with grade 2 in accordance with EN ISO 3696. 4.2 Element stock solution, fluoride (NaF); Fluoride c = 1 000 mg/l. 4.3 Hydrochloric acid (HCl), mass fraction of 37 %, having a density of approximately (HCl) 1,185 g/ml. 4.4 Perchloric acid (HClO4), m

36、ass fraction of 70 % to 72 %, having a density of approximately (HClO4) 1,68 g/ml. 4.5 Acetic acid (CH3COOH), glacial, 99 %. 4.6 Sodium acetate trihydrate (CH3COONa 3H2O), 99 %. 4.7 Trisodium citrate dihydrate (C6H5Na3O72H2O), 99 %. 4.8 Hydrochloric acid solution of 1 mol/l. To prepare: pipette 83 m

37、l hydrochloric acid (4.3) into a 1 000 ml volumetric flask (5.5) and fill to the mark with water (4.1). 4.9 Sodium acetate solution of 3 mol/l. To prepare: dissolve 408 g of sodium acetate trihydrate (4.6) in 750 ml of water (4.1). When the solution reaches room temperature (20 C to 25 C), adjust th

38、e pH to 7,0 with acetic acid (4.5), transfer to a 1 000 ml volumetric flask (5.5) and dilute to the mark with water (4.1). 4.10 Sodium citrate solution. To prepare: dissolve 222 g of trisodium citrate dehydrate (4.7) in 250 ml of water (4.1), add 28 ml perchloric acid (4.4), transfer to a 1 000 ml v

39、olumetric flask (5.5) and dilute to the mark with water (4.1). 4.11 Intermediate fluoride solution of 100 mg/l. To prepare: pipette 10 ml from the 1 000 mg/l fluoride stock solution (4.2) into a 100 ml plastic volumetric flask (5.7) and dilute to the mark with water (4.1). 4.12 Intermediate fluoride

40、 solution of 10 mg/l. To prepare: pipette 10 ml from the 100 mg/l intermediate fluoride solution (4.11) into a 100 ml plastic volumetric flask (5.7) and dilute to the mark with water (4.1). 4.13 Sodium hydroxide solution of 5 mol/l. To prepare: transfer NaOH pellets, weighing 200 g, to a 1 000 ml vo

41、lumetric flask (5.5), which is about 2/3 filled with water (4.1) and contains a magnetic stirring bar (5.4). Stir until dissolved; after cooling down take away the magnet stirrer and fill up to the mark with water (4.1) and shake. NOTE The use of sodium hydroxide solution of 1 mol/l might be more ap

42、plicable for a precise pH adjustment. DIN EN 16279:2012-09 EN 16279:2012 (E) 7 5 Apparatus Use typical laboratory apparatus with preference for plastic instead of glass for recipients, in order to avoid undesired reactions of fluoride with silicon from glass in the case of fluoride standard solution

43、s and the test sample solutions. 5.1 Laboratory grinder 5.1.1 Laboratory grinder, capable of grinding to a particle size of less than or equal to 0,5 mm. 5.1.2 Laboratory grinder, capable of grinding to a particle size of less than or equal to 0,1 mm. 5.2 Analytical balance, capable of weighing to a

44、n accuracy of 0,1 mg. 5.3 Freeze drying equipment, capable of freeze-drying liquid animal feeding stuffs. 5.4 Magnetic stirrer, with polytetrafluoro-ethylene-coated stirring bar. 5.5 One-mark volumetric flasks, of capacities 100 ml, 500 ml and 1 000 ml. 5.6 Beakers, of capacities 100 ml and 250 ml.

45、5.7 One-mark plastic volumetric flasks, of capacities 100 ml and 200 ml. 5.8 Plastic beakers, of capacities 50 ml, 100 ml and 200 ml. 5.9 Fluoride selective electrode. NOTE The use of combined electrodes (i.e. selective and reference in one) is possible. 5.10 pH combined electrode. 5.11 Reference el

46、ectrode for fluoride. 5.12 Ion-pH-meter, capable of measuring to an accuracy of 0,1 mV. 6 Sampling Sampling is not part of the method specified in this European Standard. A recommended sampling method is given in EN ISO 6497 2. It is important that the laboratory receives a sample that is truly repr

47、esentative and has not been damaged or changed during transport or storage. 7 Preparation of test sample 7.1 General Prepare the test sample in accordance with EN ISO 6498. The grinding must be performed in conditions such that the substance is not appreciably heated. The operation is to be repeated

48、 as many times as is necessary and it shall be executed as quickly as possible in order to prevent any gain or loss of constituents (such as water). DIN EN 16279:2012-09 EN 16279:2012 (E) 8 The 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 shall be thoroughly mixed