1、 STD*BSI BS EN 13191-2-ENGL 2000 E 1bZVbbS OBbblO3 8bb E BRITISH STANDARD Non-fatty food - Determination of bromide residues - Part 2: Determination of inorganic bromide The European Standard EN 13191-2:2 has the status of a British Standard ICs 67.050 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PER
2、MIITED BY COPYRIGHT LAW BS EN 13 191-2:2000 BS EN 13191-220o0 been prepared under the direction of the Consumer Amd. No. Date Products and Services Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 August 2000 O BSI 08-2000 ISBN O 680 34848 2
3、National foreword Comments This British Standard is the official English language version of EN 13191-2:2000. The UK participation in its preparation was entrusted to Technical Committee AW/-B, Food analysis - Horizontal methods, which has the responsibility to: - aid enquirers to understand he text
4、; - present to the responsible European committee any enquiries on the - monitor related international and European developments and promulgate interpretation, or proposals for change, and keep the UK interests mformed; them in the UK. A list of organizations reprented on this committee can be obtai
5、ned on request to its secretary. Cross-references “he British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index“, or by using the “Find“ fa
6、cility of the BSI Standards Eleclxonic Catalogue. A British Standard does not purport to include ali the necessary provisions of a con- Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligatio
7、ns. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 11 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued STD-BSI BS EN L3391-2-ENGL 2000 Lb2qbbS OBbbL05 b3 II EN 13191-2 EUROP
8、EAN STANDARD NORME EUROPENNE EUROPAISCHE NORM May 2000 ICs 67.050 English version Non-fatty food - Determination of bromide residues - Part 2: Determination of inorganic bromide Aliments non gras - Dtermination des rsidus de bromures - Partie 2: Dtermination des bromures inorganiques Fettarme Lebens
9、mittel - Bestimmung von Bromidrckstnden - Teil 2: Bestimmung von anorganischem Bromid This European Standard was approved by CEN on 8 April 2000. CEN members are bound to comply with the CENICENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a
10、 national standard without any alteration. Up-to-date lists and bibliographical references concerning sich national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version
11、in any other language made by traislation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as he official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, G
12、ermany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Central Secretariat: rue de Stassart, 36 8-1050 Brussels O 2000 CEN A
13、ll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13191-22000 E STD-BSI BS EN L3191-2-ENGL 2000 m lbZqbb9 OBbblOb 575 m Page 2 EN 131 91-2:2000 Contents Foreword -. . 2 1 Scope . 3 2 Normative reference . 3 3 Principle 3 4 Reagents 3 5 Ap
14、paratus 4 6 Procedure 4 7 Evaluation of results . 5 8 Confirmatory tests . 6 9 Precision 6 10 Test report . . . 7 Annex A (informative) Examples for appropriate gas chromatographic operating conditions . 8 Annex B (informative) Precision data 10 Bibliography 11 Foreword This European Standard has be
15、en prepared by Technical Committee CENiTC 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 November 2000, and confl
16、icting national standards shall be withdrawn at the latest by November 2000. This European Standard, Non-fatty foods - Determination of bromide residues, consists of two parts: Part I : Determination of total bromide as inorganic bromide Part 2: Determination of inorganic bromide The Annexes A and B
17、 are informative. According to the CENICENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Nether
18、lands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. O BSI 08-2000 STD=BSI BS EN 13191-2-ENGL 401 m Page 3 EN 131 91 -2:2000 1 Scope This European Standard specifies a gas chromatographic method for the determination of inorganic bromide residues in non-fatty foods. Generally,
19、 the maximum residue levels are expressed in terms of bromide ion from all sources but not including covalently bound bromine. The method is applicable to cereals, dried fruit, dried vegetables, dried mushrooms, fresh fruit and vegetables. It has been validated in interlaboratory studies on maize fl
20、our, carrot flakes, lettuce, potatoes, cereal flour and hazelnuts I, 2. 2 Normative reference This European Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are li
21、sted herealer. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN IS0 3696 Water for analy
22、tical laboratory use - Specification and test methods (IS0 3696:1987) 3 Principle The test portion is suspended in an aqueous solution of propylene oxide acidified with sulfuric acid whereupon inorganic bromide is extracted simultaneously and converted to a mixture of I-bromo-2-propanol and 2-bromo-
23、l- propanol 3 (derivatization A). The derivatives are partitioned into ethyl acetate and determined by gas chromatography with electron-capture detection 4, 5. As an alternative, ethylene oxide which is more difficult to handle and which is somewhat more toxic, can be used instead of propylene oxide
24、. In this case (derivatization B) inorganic bromide is converted to 2-bromoethanol 4, 5. 4 Reagents 4.1 General and safety aspects Unless otherwise specified, use reagents of recognized analytical grade, preferably for pesticide residue analysis, and only water of grade 2 according to EN IS0 3696. T
25、ake every precaution to avoid possible contamination of water, solvents, inorganic salts, etc. by plastics and rubber materials. Use only glass containers for storage and handling of all water and reagents. WARNING: Ethylene oxide and propylene oxide are highly reactive and cancerogenic. Work always
26、 in a well- ventilated fume hood. Consult the safety data sheet of the manufacturer for information and follow local instructions. To destroy excess ethylene and propylene oxide solutions, add a surplus of sodium chloride solution, shake several times and allow the mixture to stand for some hours. P
27、ropylene oxide, 9 (C3H60) of at least 995 % volume fraction. Store at approximately 4 OC. 4.2 4.3 Propylene oxide solution In a well-ventilated fume hood, pour 95 ml of ice-cold water into a 100 mi volumetric flask, and add propylene oxide (4.2) dropwise to the mark and mix well. Store in a refriger
28、ator at 4 OC. Prepare fresh daily. 4.4 Ethylene oxide (optional), 9 (C2H40) of at least 993 % volume fraction, in pressurized can fitted with valve. Store at approximately - 20 OC. 4.5 Ethylene oxide solution (optional) In a well-ventilated fume hood, pour 96 ml of ice-cold water into a 100 ml volum
29、etric flask, and add ethylene oxide (4.4) dropwise to the mark from the completely inverted, ice-cold pressurized can and mix well. Store at approximately 4 “C. Prepare fresh daily. 4.6 Sulfuric acid, C(HZS04) = 3 mol/l. O BSI 08-2000 STD=BSI BS EN 13L9L-Z-ENGL 2000 D Lb29bb7 OBbbLUB 398 D Page 4 EN
30、 13191-2:2000 4.7 Ethyl acetate Before use, check each newly opened bottle by injecting the same volume into the gas chromatograph as used in 6.3. If interfering peaks are observed, purifi the ethyl acetate by distillation. WARNING: Ethyl acetate is flammable and is irritating to eyes and respirator
31、y tract. 4.8 Ammonium sulfate 4.9 Sodium sulfate, anhydrous. Heat for 5 h at 500 “C. Cool in a desiccator. 4.10 2-Bromoethanol standard solution in ethyl acetate, p (C2H5BrO) = I mgll. 4.11 Potassium bromide. Heat for 1 h at 130 “C. 4.12 Bromide stock solution, p (Br-) = 50 mg/l. Dissolve 149 mg of
32、potassium bromide (4.1 1) in 100 ml of water, and dilute 5 ml of this solution with water to a volume of 1 O0 ml. 4.13 Bromide standard solutions Prepare appropriate dilutions of the bromide stock solution (4.12) which contain 2 pg, 5 pg, 10 pg, 25 pg and 50 pg of bromide per millilitre. 5 Apparatus
33、 Usual laboratory apparatus and, in particular, the following: 5.1 5.2 5.3 5.4 Homogenizer or high speed blender, fitted with glass jar. Test tubes, e.g. 20 ml, with ground joint. Conical flask, e.g. 200 ml, with ground joint. Gas chromatograph, equipped with an electron-capture detector. 6 Procedur
34、e 6.1 Extraction and denvatization 6.1.1 Method with propylene oxide (Derivatization A) For cereals and dried materials, weigh 1 ,O g of the finely ground powder (test portion) into a conical flask (5.3), slurry in 10 ml of water, add 10 ml propylene oxide solution (4.3) and add 2 ml of sulfuric aci
35、d (4.6). For fresh fruit and vegetables, homogenize the material in a blender .I), weigh 10,O g of the homogenate (test portion) into a conical flask, and add 10 ml of propylene oxide solution and 2 ml of sulfuric acid. In both cases, stopper the flask and allow to stand for 1 h at room temperature.
36、 6.1.2 Method with ethylene oxide (Derivatization B) For cereals and dried materials, weigh I ,O g of the finely ground powder (test portion) into a conical flask (5.3), slurry in 10 ml of ethylene oxide solution (4.5) and add 1 ml of sulfuric acid (4.6). For fresh fruit and vegetables, homogenize t
37、he test sample in a blender I), weigh 5,O g of the homogenate (test portion) into a conical flask, and add 5 ml of ethylene oxide solution and 1 ml of sulfuric acid. In both cases, stopper the flask and allow to stand for 30 min at room temperature. 6.2 Partition Add 50 ml of ethyl acetate (4.7) and
38、 4,O g of ammonium sulfate (4.8). Stopper the flask, shake vigorously for 1 min, and then allow to stand for approximately 20 min with occasional shaking. Decant approximately 10 ml of the upper organic phase into a test tube (5.2). Add 0,5 g of sodium sulfate (4.9), stopper the test tube and shake
39、vigorously (sample test solution). 6.3 Gas chromatography Inject equal volumes of the sample test solution derived from 6.2 and either of the solutions obtained in 6.5 for the calibration curve (derivatization A) or of dilutions of the 2-bromoethanol standard solution (4.1 O) (derivatization B) into
40、 the gas chromatograph (vi) . O BSI 08-2000 _ STD-BSI BS EN 13171-2-ENLL 2000 W lb24bb9 ObLL 284 II Page 5 EN 131 91 -212000 Make sure that the gas chromatographic conditions (column length, stationary phase type, injector, detector and column temperatures, gas flow rates, etc.) are such that the se
41、paration of the bromine derivatives from possible interfering peaks originating from the samples is as complete as possible. Typical gas chromatographic operating conditions are given in Annex A. NOTE 1: Due to their higher separation efficiency, capillary columns are preferably used. NOTE 2: Two ch
42、loropropanols (derivatization A) or 2-chloroethanol (derivatization B), respectively, are formed from chloride ions naturally occurring in the sample material. Their peaks, however, have shorter retention times than the corresponding bromo derivatives and do not interfere with the determination. 6.4
43、 Prepare reagent blanks and cany out spiked recovery tests at levels appropriate to the maximum residue level. The chromatogram of the reagent blank should not show a peak at the retention times of the bromopropanols (derivatization with propylene oxide) or of 2-bromoethanol (derivatization with eth
44、ylene oxide), respectively. NOTE: Occasionally, a tailing peak with a longer retention time appears which is due to propylene glycol or ethylene glycol, respectively, and does not interfere with the determination. 6.5 Standard solutions Prepare appropriate dilutions of the bromide stock solution (4.
45、12) which contain 2 pg, 5 pg, 10 pg, 25 pg and 50 pg of bromide per millilitre. To 1,OO ml each of the bromide standard solutions (4.13), add 9 ml of water, 10 ml of propylene oxide solution (4.3) and 2 ml of sulfuric acid. Allow to stand for 1 h at room temperature and follow the procedure in 6.2 a
46、nd 6.3. Plot a calibration curve from the peak areas (or peak heights) obtained for the higher one of the two bromopropanol peaks against the mass of bromide added. Test for interferences and recoveries 7 Evaluation of results 7.1 Read off the mass of bromide present in the injection volume from the
47、 calibration curve. Calculate the mass fraction w of bromide, in milligrams per kilogram, using equation (1): Calculation for propylene oxide derivatization A ms where: X m, is the mass of bromide read off from the calibration curve, in micrograms; is the mass of the test portion, in grams. If the r
48、esults indicate that the amount of residue approaches or exceeds the maximum residue level, examine at least two further test portions. 7.2 Measure the peak height (or peak area) obtained from the sample test solution and compare it with the peak heights (or peak areas) obtained from appropriate dil
49、utions of the 2-bromoethanol standard solution (4.10). Calculate the mass fraction w of bromide, in milligrams per kilogram, using equation (2): Calculation for ethylene oxide derivatization B where: m, is the mass of the test portion, in grams; Vend is the volume of ethyl acetate used for partition in 6.2 (here: 50), in millilitres; V, is the injection volume of the sample test solution, in microlitres; ms is the mass of 2-bromoethanol injected with standard solution, in nanograms; FA is the peak area or peak height, obtained for the injected sample
