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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 12396-1:1999 The Eu
2、ropean Standard EN 12396-1:1998 has the status of a British Standard ICS 67.050 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Non-fatty foods Determination of dithiocarbamate and thiuram disulfide residues Part 1: Spectrometric method Licensed Copy: sheffieldun sheffieldun,
3、na, Sat Oct 28 08:46:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 12396-1:1999 This British Standard, having been prepared under the direction of the Consumer Products and Services Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 March
4、 1999 BSI 03-1999 ISBN 0 580 30690 9 Amendments issued since publication Amd. No.DateText affected National foreword This British Standard is the English language version of EN 12396-1:1998. The UK participation in its preparation was entrusted to Technical Panel AW/-/3, Food analysis Horizontal met
5、hods, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promu
6、lgate them in the UK. A list of organizations represented on this panel can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the sectio
7、n entitled International Standards Correspondence Index, or by using the Find facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compl
8、iance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 8, an inside back cover and a back cover. Licensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 08:46
9、:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1998 CEN All rights of exploitation in any form and by any means reserved worldwide
10、for CEN national Members. Ref. No. EN 12396-1:1998 E EUROPEAN STANDARDEN 12396-1 NORME EUROPE ENNE EUROPA ISCHE NORM October 1998 ICS 67.040 Descriptors: food products, chemical analysis, determination of content, pesticides, fungicides, pesticide residues, spectrophotometric analysis English versio
11、n Non-fatty foods Determination of dithiocarbamate and thiuram disulfide residues Part1: Spectrometric method Aliments non gras De termination des re sidus de dithiocarbamates et de bisulfures de thiurame Partie 1: Me thode spectrome trique Fettarme Lebensmittel Bestimmung von Dithiocarbamat- und Th
12、iuramdisulfid- Ru cksta nden Teil 1: Spektralphotometrisches Verfahren This European Standard was approved by CEN on 2 October 1998. 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 sta
13、ndard without any alteration. Up-to-date lists and bibliographical references concerning such 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 in any other
14、language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Gree
15、ce, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 08:46:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 2 EN 12396-1:1998 BSI 03-1999 Foreword This European Standard has bee
16、n 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 April 1999, and conflicting
17、 national standards shall be withdrawn at the latest by April 1999. This European Standard EN 12396, Non-fatty foods Determination of dithiocarbamate and thiuram disulfide residues, consists of three parts: Part 1: Spectrometric method; Part 2: Gas chromatographic method; Part 3: Xanthogenate method
18、. According to the CEN/CENELEC 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, Netherlands, Norway, P
19、ortugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword2 1Scope3 2Normative references3 3Principle3 4Reagents3 5Apparatus4 6Sampling5 7Preparation of the samples5 8Procedure5 9Expression of the results6 10Confirmatory tests6 11Precision7 12Test report7 Annex A (informative
20、) Precision data8 Annex B (informative) Bibliography8 Licensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 08:46:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 3 EN 12396-1:1998 BSI 03-1999 1) r is the mass concentration. 1 Scope This European Standard specifies a spectrometric method for the
21、determination of residues of dithiocarbamates and thiuram disulfides, which release carbon disulfide under the described conditions (e.g. mancozeb, maneb, propineb, thiuram, zineb). It is applicable to such compounds in and on fruits and many vegetables and also in and on cereals and other foodstuff
22、s of plant origin. Only the quantification of the whole group is possible using this method but not the identification of individual compounds. Generally the maximum residue limits (MRLs) are expressed in terms of carbon disulfide. 2 Normative references This European Standard incorporates by dated
23、or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard onl
24、y when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 12393-1:1998, Non-fatty foods Multiresidue methods for the gas chromatographic determination of pesticide residues Part 1: General considerations. EN 12396-2, Non-
25、fatty foods Determination of dithiocarbamate and thiuram disulfide residues Part 2: Gas chromatographic method. ISO 1750, Pesticides and other agrochemicals Common names. 3 Principle The sample is heated with hydrochloric acid and tin(II)chloride to release carbon disulfide from any dithiocarbamates
26、 and/or thiuram disulfide present. The carbon disulfide is separated and purified by distillation and collected in an ethanolic solution of copper(II)acetate and diethanolamine. With copper(II)acetate and diethanolamine, the carbon disulfide forms two yellow copper(II)-N,N-bis(2-hydroxy-ethyl)-dithi
27、ocarbamate complexes with the molar ratio Cu:CS2= 1:1 and 1:2. The absorption of these reaction products is measured in a spectrometer at a wavelength of 435 nm and the concentration of dithiocarbamate and/or thiuram disulfide residues is calculated and expressed in terms of milligrams (mg) of carbo
28、n disulfide per kilogram (kg) of foodstuff. For further information on the principle of this method, see 1 to 4. 4 Reagents 4.1 General Unless otherwise stated, use reagents of recognized analytical grade, preferably for pesticide residue analysis, and only distilled or demineralized water. Label al
29、l standard containers with name and purity of all pesticides. For the full chemical names and structures, see ISO 1750. Take 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
30、of all water and reagents. 4.2 Carbon disulfide, colourless, mass concentration of at least 99 %. If stored at 220 8C it is stable for 2 years to 3 years. 4.3 Diethanolamine, at least 99 % of mass concentration. 4.4 Ethanol, mass concentration of at least 95 %. 4.5 Hydrochloric acid, concentrated, r
31、20(HCl) = 1,16 g/ml. 4.6 Sulfuric acid (optional), concentrated, r20(H2SO4) = 1,84 g/ml 4.7 Sodium hydroxide solution, r(NaOH) = 100 g/l1). 4.8 Copper(II)acetate solution, r(Cu(CH3COO)2H2O) = 400 mg/l. Weigh 400 mg of copper(II)acetate monohydrate, to the nearest 1 mg, with gentle warming only, in 2
32、50 ml of ethanol (4.4). Dilute 25 ml of this solution to 100 ml with ethanol. 4.9 Lead acetate solution (optional), r(Pb(CH3COO)23H2O) = 300 g/l. 4.10 Tin(II)chloride solution, r(SnCl22H2O) = 40 g/100 ml in concentrated hydrochloric acid (4.5). 4.11 Tin(II)chloride - hydrochloric acid solution, r(Sn
33、Cl22H2O) = 3,3 g/100 ml. Mix 20 ml of tin(II)chloride solution (4.10) with 20 ml of concentrated hydrochloric acid (4.5) and add carefully 200 ml of water. 4.12 Zinc acetate solution (optional), r(Zn(CH3COO)2) = 20 g/100 ml. 4.13 Carbon disulfide stock solution Weigh to the nearest 10 mg a stoppered
34、 50 ml volumetric flask with a ground glass neck containing 40 ml of ethanol (4.4). Add approximately 1 ml of carbon disulfide (4.2) (equivalent to approximately 1,25 g) using a pipette, close the flask at once and re-weigh to the nearest 10 mg to obtain the exact mass of carbon disulfide by differe
35、nce. Dilute to the mark with ethanol and mix well. Prepare freshly for each calibration curve. Licensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 08:46:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 4 EN 12396-1:1998 BSI 03-1999 1Liebig condenser4cylindrical flask or round bottomed flask 2dr
36、opping funnel5absorption tubes 3gas inlet tube6Widmer helix Figure 1 Decomposition and distillation apparatus 4.14 Carbon disulfide standard solution Pipette 5 ml of carbon disulfide stock solution (4.13) into a 50 ml volumetric flask and dilute to the mark with ethanol (4.4). Pipette 5 ml of this d
37、ilution into a 250 ml volumetric flask and dilute to the mark with ethanol. 1 ml of this standard solution is equivalent to approximately 50 mg of carbon disulfide. Prepare freshly for each calibration curve. 4.15 Colour reagent Successively introduce 100 ml of ethanol (4.4), 30 ml of copper(II)acet
38、ate solution (4.8) and 25 g of diethanolamine (4.3) into a 250 ml volumetric flask, and dilute to the mark with ethanol. 5 Apparatus 5.1 General Thoroughly clean glassware shall be used. See EN 12393-1:1998, 5.1 for the cleaning of glassware. Usual laboratory equipment and, in particular, the follow
39、ing. 5.2 Decomposition and distillation apparatus, consisting of a 1 l or 2 l round bottomed three necked flask or cylindrical flask with a three necked adapter, a dropping funnel, a gas inlet tube, an ascending Liebig condenser, three absorption tubes, the last two preferably fitted with a Widmer h
40、elix, connected by spherical socket joints, the first being attached to the Liebig condenser (see Figure 1). Licensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 08:46:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 5 EN 12396-1:1998 BSI 03-1999 5.3 Flowmeter. 5.4 Heating mantle, electrically o
41、perated, at least 450 W; or gas burner fitted with a Babo funnel and flask holder 5.5 Spectrometer, suitable for measurements at a wavelength of 435 nm, with a 1 cm glass or quartz cell. A double beam spectrometer should preferably be used. 5.6 Water jet pump, attached to the last absorption tube, o
42、r a source of nitrogen under pressure, attached to the gas inlet tube. 6 Sampling Prepare the laboratory sample according to generally recommended methods of sampling to achieve a representative part of the product to be analysed. NOTESampling procedures for the official control of pesticide residue
43、s in and on fruits and vegetables are given in EEC directive 79/700/EEC 5. 7 Preparation of the samples 7.1 Test sample If the sample reaches the laboratory frozen, store it at 220 8C before analysis. Where possible, carry out the analysis of fresh samples immediately after their arrival in the labo
44、ratory. Do not analyse a laboratory sample which is wholly or extensively spoiled. For analysis take only the portion of the laboratory sample to which the maximum residue limit applies. No further plant-parts may be removed. A record of the plant-parts which have been removed shall be kept. The sam
45、ple thus prepared is the analytical sample. If the sample cannot be analysed immediately, it may be stored at 0 8C to 5 8C for no longer than 2 days before analysis. The reduction of the analytical sample shall be carried out in such a way that representative portions are obtained (e.g. by division
46、into four and selection of opposite quadrants). When the samples are in small units (e.g. small fruits, vegetables, cereals), the analytical sample shall be thoroughly mixed before weighing out the test portion. When the samples are in larger units, take wedge-shaped sections (e.g. large fruits and
47、vegetables) or cross-sections (e.g. cucumbers) which include the outer surface from each unit. NOTEThe residues of dithiocarbamate and thiuram disulfide, which are on the surface of the plant-parts and are not systemic, decompose rapidly especially in chopped samples. Therefore precautions should be
48、 taken to avoid decomposition. If samples have to be stored for more than 2 days, they shall be deep-frozen at 220 8C. To ensure that even after thawing representative samples can be taken, prepare portions of the product which are each sufficient for one analysis. 7.2 Test portion Weigh out test po
49、rtions of masses up to 200 g to an accuracy of1 %. After weighing out the test portion, remove any parts which would interfere with the analytical procedure. In the case of stone fruits, the stones are removed after weighing out. The basis for the calculation of the residue mass fraction is the mass of the original test portion (with stones). The test portion shall not be cut or reduced to smaller pieces than can just pass the neck of the reaction flask, as the residues of dithiocarbamate and thiuram disulfide fall t
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