1、BRITISH STANDARD * * Ln The European Standard EN 15281 : 1996 has the status of a British Siandard ICs 67.040 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 1528-1 : 1997 Fatty food - Determination of pesticides and polychlorinated biphenyls (PCBs) Part 1. General BS EN
2、 1628-1 1997 AmdNo. The foiiowing BSI references relate to the work on this standard Committee reference Awl43 Draft for comment 94506374 DC Committees responsible for this British Standard Date Tex affected The preparation of this British Standard was enrusted to Technid Panel AW/-B, Food analysis
3、- Horizontal methods, upon which the following bodies were representd Association of Public Analys Department of “kade and Industry (Laboratory of the Government Chemist) Food and Drink Federation Institute of Food Science and Technology Mixusby of Agriculture Fisheries and Food Royal Society of Che
4、mistry This British Standard, having been prepared under the direction of the Consumer Products and SeMces Sector Board, was published under the authority of the Standards Board and comes into effect on 15 June 1997 O BSI 1997 ISBN O 880 27379 2 STD-BSI BS EN 1528-1-ENGL 1777 Lb24bbS Ob20044 543 BS
5、EN 1628-1 : 1997 Contents page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 15281 3 O BSI 1997 i STD-BSI BS EN 1528-1-ENGL 1997 9 lb24bb9 Ob2001iS Li8T BS EN 1628-1 : 1997 National foreword This British Standard has been prepared by Technical Panel AW/-B and i
6、s the English language version of EN 15281: 1996 Fatty food - Determination of pesticides and polychlorinated biphenyls (PCBs) Part 1: General published by the European Committee for Standardization (CEN). EN 15281 was produced as a resuit of international discussions in which the United Kingdom too
7、k an active part. Cross-references Publication referred to EN 15282 : i996 EN 15283 : 1996 EN 1528-4: i996 Corresponding British Standard BS EN i5282 : 1997 Fatty food - Determination of pesticides and polychorimted biphenyls (1DcBs) Part 2 : Extraction of fat, pesticides and PCBS, and determination
8、 of fat content BS EN 15283 : 1997 Fatty food - Determination of pesticides and polychlorinated biphenyls (PCBs) Part 3 : Clean-up methods BS EN 15284 : 1997 Fatty food - Determination of pesticides and polychlorinated biphenyls (PCBs) Part 4 : Determimtwn, confimtorg tests, miscellanecyus The Techn
9、ical Commmittee has reviewed the provisions of IS0 1750, to which nonnative reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. IS0 5725 : 1986, to which informaiive reference is made in the text, has been superseded by IS0 57251 : 1994,
10、 IS0 57252 : 1994, IS0 5725-3 : 1994, IS0 57254 : 1994 and IS0 5725-6 : 1994 which are identical with BS IS0 5725 Accumcy (trueness and prsc2simL) of nzeusumt methods and results, BS IS0 57251 : 1994 Geneml principies and definitwns, BS IS0 57252 : 1994 Basic method for the determination of repeatnb
11、dity and rqmducibility of a stundud measurement method, BS IS0 5725-3 : 1994, Intermediate nzeusum of the precision of a stanad mec2surement method, BS IS0 5725-4 : 1994 Basic method for the determinatbn of the trueness of a standard nzeusumt method, and BS IS0 5725-6 : 1994 Use in pmctice of aracg
12、ValueS. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside hnt cover, pages i and ii, the EN title page, pages 2 to 12, an inside back cover and a back cover. u O BSI 1997 * M * STD-BSI BS EN
13、 1528-1-ENGL 1777 = LbZLibb7 ObZ004b 31b EUROPEAN flmm EN 1528.1 NO= EXJR0PEE”E EUROP- NORM November 1996 ICs 67.040 Descriptors: Food products, edible fats, chemical analysis, determination of content, pesticides, poiyciorobiphenyl, gas chromatogmphy, generalities English version Fatty food - Deter
14、mination of pesticides and polychlorinated biphenyls (PCl3s) - Part 1 : General Aliments gras - Dosage des pesticides et des polychlombiphnyles (PCB) - Partie 1 : Gnralit if this is not possible, redisti the water, solvents, and reagents used as described in annex B and check their purity (see 4.2).
15、 Note that ion-exchange resins used for demineraized water can be a source of interferences. punsl and periodically activate adsorbents accorduig to the requirements of the different analytical methods; check thek purity (see 4.2). We every precaution to avoid possible contaminaton of water, solvent
16、s, adsorbents etc. hm plastics and rubber materials. If an interference is encountered in a reagent blank determimtion, then check the purity of ail reagents used. 4.2 Check for purity of reagents 4.2.1 Solvents Concentrate solvents by the factor involved in the respective method to be used “kt for
17、purity by GC under the same conditions as used in the method The chromatogram should not show any interfering impurity. Extract or concentrate acetonitde, dimethylformamide and dichioromethane in the same volume as use in the method and examine the resuiting solution as above by GC. 4.2.2 Water Extr
18、act 10 parts by volume of water with one part by volume of n-hexane or light petsolem, dichloromethane or any other non water miscible solvent used in the method. Separate the organic phase, concenkk by the factor involved in the respective method and test for purity by GC under the same conditions
19、as used in the method. The chromatogram should not show any interfering impurity. 4.2.3 Inorganic salts Extract inorganic salts, for example sodium chloride, after purincation according to annex B or the requirements of the different analytical methods and any aqueous solution used, with whexane or
20、light petroleum, dichioromethane or any other non water miscible solvent used in the method Concentrate the extract by the factor involved in the respective method and test by GC under the same conditions as used in the method The chromatogtan should not show any interfering impurity. 4.2.4 Adsorben
21、ts Elute an amount of adsorbent equal to that used in the analytical method with the corresponding type and volume of solvent or solvent mixture. Concentrate the eluate as indicated in the andytid method and test for purity by GC. The chromatogram should not show any interfering impurity. Check the
22、activity of adsorbents regularly, for example as described in 6.3.9 of EN 15283 : 1996. 4.2.6 Standard materials and soiutwns Use materiais of at least 95 % purity and traceable quaiity as stanards for residue analysis. Ensure dilute solutions are prepared and checked frequent peroxides. 6.4 Solvent
23、 evaporators 6.4.1 General Solvent evaporators shail have a thermostable water bath, capable of being controlled between ambient temperature and 100 “C and preferably a controller for the vacuum. The effect of the solvent evaporator on the loss of volatile residues should be checked periodim. A keep
24、er (e.g. propylene glycol, mundearte or hexadecane) may be used to minimize losses of pesticides in certain cases. Solvent evaporators (see 6.4.2 to 6.4.4) may be used for concentraimg large solvent volumes. For small volumes, the use of a gentle stream of pure, dry nitrogen is more advisable. 6.4.2
25、 KwlemaDanish mapomtor i21 (or equivalent) with or without Monaljng column, which is heated on a thermostable water bath. 6.4.3 Roi!ury fzlm evaporator (commercially available), which requires a source of vacuum, and can be heated up to a temperature of 50 “C. 6.4.4 Rotary vacuum mapomtor (commercml
26、ly available), rotating at speeds up to 1300 min-l, which requires a source of vacuum and which shall have a thermostable water bath. O BSI 1997 STD*BSI BS EN L528-L-ENGL 1777 M lbZLibb9 UbZ.0052 bLT Page 7 EN 1528-1 : 1996 6.6 Homogenizers If homogenizers are used, take care to ensure that they are
27、 spark proof and kept free from contaminati on. Check bottomdrive macerators for leaks around the drive. The various seals can be a source of con tIUnhti0n 6.6 Centriniges If required, explosion proof centrifuges may be used, in which centrifuge tubes with severai hundred millilitres of emulsion can
28、 be spun at roatiod frequencies of 2000 min-1 to 4 min-1 or more. 6.7 Gas chromatography Gas chromatography apparatus as described in clause 4 of EN 15281 : 1996 shall be used 6 Procedure 6.1 General operators should thoroughly familiarize themselves with the method before starhg reguiatry analyses.
29、 Reagent blanks shall be performed and established as being satidactry. Also, spiked recovery experiments over a broad range of levels includmg the maximum residue limit should be carried out and found to be satisfactory (see clause 9). Additiom, an appropriate reference materiai should be analysed
30、whenever it is available. Exactly the same procedure should be followed for each analysis and no variations shall be introduced. Part 7 of CODEX Recommendations for methods of analysis for pesticide residues should be observed 9. 6.2 Small scale procedures If, in some cases, extractions of fats and
31、residues are to be carried out only with smaii amounts of sample, solvents and materials (smail scale procedure), choose a compatible small scale procedure for clean-up. Jf, however, the results obtained by a small scale procedure show that the residues approach or exceed the maximum residue limit,
32、choose the second extraction and clean-up procedure for confirmation with larger amounts of sample, solvents and materiais. 6.3 Preparation of the test sample Carry out the preparation of test samples immediately on their arrivai. If this is not possible, store the samples in suitable, well closed c
33、ontainers under deep freeze conditions of at least - 18 “C. Ensure that samples delivered to the laboratory which are wholly or extensively spoiled are not used for analysis. It is not always possible to complete analyses in a day and somemes it is necessary to store sample exira at least two column
34、s of different polarities should be used The procedures listed in EN 1528 4 : 1996 as giasscapiiiary GC, thin layer chromatography (TLC), the GC of oxidation and other conversion products and similar techniques are of value. Results obtained using MS present the most definitive evidence for connnnat
35、ionhdentifwition purposes. NOTE. EN 1528-4 : 1996 Determination, confirmatory tests, miscellaneous gives guidance on some recommended techniques for the determination of pesticides and PCBs in fatty foodstuffs and on confirmatory tests, and lists a clean-up procedure for the removal of the bulk of l
36、ipids when analysing large quantities of fat 9 Evaluation 9.1 Calculation Calculate the concentration of residues of pesticides or PCB congeners in the sample hm the ratio of the chromatograms of sample and standard or standard series. Express this concentration on the whole product or on the fat (s
37、ee clause 11) according to the requirements of the analysis. The mean of recoveries from replicate determinations should fali within the range 70 % up to 110 96 O BSI 1997 STD-BSI BS EN 1528-1-ENGL 1777 Lb24bb7 Ob20054 q72 U Page 9 EN 1628-1 : 1996 NOTE. When working near the limit of determination,
38、 this range may not be achieved. 9.2 Precision 9.2.1 General The precision of the anaiytical method should be evaluated in accordance with the requirements of IS0 5725 13. Some general criteria, based on experience, are given in 9.2.2 to 9.2.3 as guidance for the analyst. 9.2.2 Repeatability conditi
39、ons Each laboratory should periodidy determine if its results under repeatability conditions are acceptable by analysing samples which have been spiked with appropriate stand materiah at suitable concentrations, e.g. near to the maximum residue limis, or preferably by using samples with incurred res
40、idues. Repeatability conditions are dened as conditions under which mutualy independent test resuits are obtained with the same method on identical test material in the same laboratory by the same operator using the same equipment within short intervals of time. 9.2.3 Reproducbily conditions Reprodu
41、cibility conditions are defined as conditions under which test results are obtained with the same method on identical test material in different laboratories with different operators using different equipment. Table 3 shows examples of acceptable diferences of test results under reproducibility cond
42、itions 141. Table 3. Examples of acceptable differences of test results under reproducibility conditions Residue level Difference (k) 1.0 0.25 (in this example 0,Ol mgkg is near the iimit of determination.) Determine intermediate values by interpolation from a log-log Wh. The practical limit of dete
43、mination depends on the degree of purification, the nature of the substrate and the GC conditions (particuiariy the type and temperature of the column, the carrier gas and the sensitivity of the detector). Since these conditions cannot be laid down edy, the practical limit of determination should be
44、 established for each method and in each laboratry In general, the practical limit of detemination for a residue should be at least one- tenth of its maximum residue limit. If, however, the maxjmum residue limit is 0,05 mg or less, a practical limit of determination onefifth of this value is sacient
45、, except where the maximum residue limit is set at or about the level of determination 11 Expression of results Express the pesticide or PCB congener content according to current legislation. Do not correct the mean concenbtion for the percentage recovery of the residue. Where no residue approaches
46、or exceeds the maximum residue hit, report the value found from a single determination. In cases where one or more residues approach or exceed the maximum residue limit proceed as follows. a) State the mean concentration and range for each residue. If blank dues did occur, they should be reported se
47、parately without correcting the mean concenmtions of the residue. b) State the mean percentage recovery and practical limit of dekmination for each relevant residue. 12 Rst report The test report shall contain at least the following data: - ail information necessary for the identification of the sam
48、ple; - a reference to the European standard in question or to the method used; - the results and the units in which the results have been e- - any operations not specified in the method or regarded as optional. 10 Practical limit of determination Theoretidy, the practical limit of determination in t
49、he sample concerned is defined as that concentration of the pesticide or PCB congener residue (in milhgmm per kilogram) which would correspond, on a chromatogram of an extract of the sample, to the lowest measurable peak area or height, with an acceptable degree of confidence in the redt. O BSI 1997 STD-BSI BS EN L528-2-ENGL 2777 m LbZLibb7 0b20055 327 m Page 10 EN 1628-1 : 1996 Annex A (normative) Applicability of methods Table A.l Applicability of methods A to H according to reference given in literature Compounds) Organochlorine pe
