1、BRITISH STANDARD BS EN ISO 12193:2004 Incorporating Corrigendum No. 1 Animal and vegetable fats and oils Determination of lead by direct graphite furnace atomic absorption spectroscopy The European Standard EN 12193:2004 has the status of a British Standard ICS 67.200.10 BS EN ISO 12193:2004 This Br
2、itish Standard was published under the authority of the Standards Policy and Strategy Committee on 25 February 2004 BSI 17 March 2004 ISBN 0 580 43492 3 National foreword This British Standard is the official English language version of EN ISO 12193:2004. It is identical with ISO 12193:2004. It supe
3、rsedes BS EN ISO 12193:2000 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee AW/307, Oil seeds animal and vegetable fats and oils, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its
4、secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic C
5、atalogue or of British Standards Online. 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 does not of itself confer immunity from legal obligations. aid enquirers to understa
6、nd 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 promulgate them in the UK. Summary of pages This document comprises a
7、 front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, the ISO title page, pages ii and iii, a blank page, pages 1 to 7 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publicatio
8、n Amd. No. Date Comments 15083 Corrigendum No. 1 17 March 2004 Corrected EN ISO foreword pageEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM ENISO12193 February2004 ICS67.200.10 SupersedesENISO12193:1999 Englishversion AnimalandvegetablefatsandoilsDeterminationofleadby directgraphitefurnaceatomicabso
9、rptionspectroscopy(ISO 12193:2004) CorpsgrasdoriginesanimaleetvgtaleDtermination delateneurenplombparspectromtriedabsorption atomiquedirecteavecfourengraphite(ISO12193:2004 TierischeundpflanzlicheFetteundleBestimmungvon BleidurchdirekteGraphitofen Atomabsorptionsspektrometrie(ISO12193:2004) ThisEuro
10、peanStandardwasapprovedbyCENon19February2004. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtai
11、nedonapplicationtotheCentralSecretariatortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCentralSecretariathasthesamestatusast heofficial versions
12、. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,Denmark,Estonia,Finland,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMM
13、ITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2004CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.ENISO12193:2004:ECORRECTED20040225 Foreword Thisdocument(ENISO12193:2004
14、)hasbeenpreparedbyTechnicalCommitteeISO/TC34 “Agriculturalfoodproducts“incollaborationwithTechnicalCommitteeCEN/TC307“Oilseeds, vegetableandanimalfatsandoilsandtheirbyproductsMethodsofsamplingandanalysis“, thesecretariatofwhichisheldbyAFNOR. ThisEuropeanStandardshallbegiventhestatusofanationalstanda
15、rd,eitherbypublicationof anidenticaltextorbyendorsement,atthelatestbyAugust2004,andconflictingnational standardsshallbewithdrawnatthelatestbyAugust2004. ThisdocumentsupersedesENISO12193:1999. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsof thefollowingcountriesarebou
16、ndtoimplementthisEuropeanStandard:Austria,Belgium, Cyprus,CzechRepublic,Denmark,Estonia,Finland,France,Germany,Greece,Hungary, Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland, Portugal,Slovakia,Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. Endorsementnotice The
17、textofISO12193:2004hasbeenapprovedbyCENasENISO12193:2004withoutany modifications. ENISO12193:2004 Reference number ISO 12193:2004(E)NINRETOITALAN ADNATSDR OSI 13912 ceSond deition -400210-20 Animal and vegetable fats and oils Determination of lead by direct graphite furnace atomic absorption spectro
18、scopy Corps gras dorigines animale et vgtale Dtermination de la teneur en plomb par spectromtrie dabsorption atomique directe avec four en graphite Referecne unbmer OSI 39121002:)E(4INTERNATIONAL STANDARD ISO 12193 Second edition 2004-02-01 Animal nad vegeelbat tafs nad slio imreteDntanoi of b daely
19、 ihparg tceridet canrufta ecimo rosbapits nopeccsortopy roCsp rgsa rodigisen aminela v tegatel tD reimnoitad nl eet aruen p nelmop bra sceprtmortie sbadrotpoita nimoeuq ridectva ece ruof ne rghpaeti ENISO12193:2004 ii ENISO12193:2004 iiiForeword ISO (the International Organization for Standardizatio
20、n) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be rep
21、resented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards a
22、re drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Internatio
23、nal Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 12193 was pr
24、epared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 11, Animal and vegetable fats and oils. This second edition cancels and replaces the first edition (ISO 12193:1994), which has been technically revised. ENISO12193:2004blankINTENRATIONAL TSANDADR IS:39121 O4002(E)1Animal and veg
25、etable fats and oils Determination of lead by direct graphite furnace atomic absorption spectroscopy 1 Scope This International Standard specifies a method for the determination of trace amounts ( 0,001 mg/kg) of lead in all types of crude or refined edible oils and fats. 2 Principle The oil or fat
26、is atomized in a graphite furnace, with or without a platform, connected to an atomic absorption spectrometer which has been previously calibrated using standard solutions of an organo compound of lead. The metal content is measured from the observed absorbance at a wavelength of 283,3 nm. 3 Reagent
27、s Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or demineralized water or water of equivalent purity. 3.1 Cyclohexane, analytical grade. 3.2 Lecithin, containing 2 % phosphorus. 3.3 Matrix modifier: 2 % (by mass/volume) lecithin solution prepared by diss
28、olving 2 g of lecithin (3.2) in 100 ml of cyclohexane (3.1). 3.4 Blank oil, refined. Any edible oil is suitable, stored in a metal-free polyethylene bottle. The lead content of the oil shall not be greater than 0,001 mg/kg. 3.5 Lead standard stock solution, c(Pb) = 10 mg/kg. This is prepared by appr
29、opriate dilution of an organometallic standard with the blank oil (3.4). NOTE A suitable standard is available from the following companies: 1) Continental Oil Company, Ponca City, Oklahoma, USA (Conostan, 5 000 mg/kg); Merck KGaA, Darmstadt, Germany Certipur 115051, lead standard dissolved in oil,
30、c(Pb) = 1 g/kg in standard oil; VWR International Certipur 1.15051, lead standard dissolved in oil, c(Pb) = 1 g/kg in standard oil; VWR International Specpure ALFA019527.AD, lead, Organic AAS standard solution, Specpure, c(Pb) = 1 000 mg/g. 1) These are examples of suitable products available commer
31、cially. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of these products. ENISO12193:20042 3.6 Lead standard working solutions: c(Pb) = 0,02 mg/kg, 0,05 mg/kg and 0,100 mg/kg, prepared daily by diluting the 10 mg/kg
32、 stock solution (3.5) with blank oil (3.4). 3.7 Argon, of minimum purity 99,99 %. 4 Apparatus 4.1 Polyethylene or polypropylene capped bottles, 20 ml, metal free. The polyethylene or polypropylene capped bottles are made metal free in the following way. Clean the bottles thoroughly with warm nitric
33、acid, rinse with distilled water and dry the bottles in a drying oven at about 80 C. 4.2 Micropipettor, 20 l. 4.3 Pipettor tips. 4.4 Electric oven, regulated at 60 C 2 C. 4.5 Atomic absorption spectrometer, equipped with either “peak height” mode and printer, or “area” mode and pen-recorder (full-sc
34、ale response in 0,2 s), together with the appropriate electrode-less discharge lamp (or hollow cathode lamp) and deuterium or Zeeman background corrector. 4.6 Graphite furnace atomizer, placed in the atomic absorption spectrometer (4.5), equipped with a control unit for temperature programming. 4.7
35、Graphite tube, normal (uncoated) or coated (pyrolytic). 4.8 Pyrolytic platform, in combination with uncoated or pyrolytically coated graphite tube. Both atomization with and without the platform may be used. The accuracy and the sensitivity with the platform is twice as good as without the platform.
36、 5 Sampling Laboratory samples of at least 1,5 g shall be stored in metal-free bottles (4.1). It is important that the laboratory receive a sample that is truly representative and has not been damaged or changed during transport or storage. Sampling is not part of the method specified in this Intern
37、ational Standard. A recommended sampling method is given in ISO 5555. 6 Procedure 6.1 Treatment of samples, blanks and standards 6.1.1 Place all samples and standard working solutions (3.6) in the oven (4.4) set at 60 C. 6.1.2 Shake samples vigorously. 6.1.3 Weigh 5,0 g of sample into a 20 ml bottle
38、 (4.1), together with 5,0 g of matrix modifier (3.3), and mix thoroughly. 6.1.4 Carry out steps 6.1.2 and 6.1.3 also for the three standard working solutions (3.6) and the blank oil (3.4). ENISO12193:2004 36.2 Preparation of apparatus 6.2.1 Switch on the atomic absorption spectrometer (4.5) and the
39、background correction (D 2or Zeeman). 6.2.2 In accordance with the manufacturers instructions supplied with the spectrometer, adjust the lamp current, slit, wavelength and amplification. The required wavelength is 283,3 nm. 6.2.3 Optimize the position of the graphite furnace atomizer (4.6) in the at
40、omic absorption spectrometer and set the required programme on the control unit of the furnace. Use the measuring parameters given in Tables 1 and 2. If available, place the platform (4.8) in the graphite tube. 6.2.4 Before each injection, pretreat the pipettor tip (4.3) by pipetting and then discar
41、ding 20 l of cyclohexane. Programmes for the graphite furnace atomizer are given in Tables 1 and 2. Table 1 Uncoated tube without platform, with maximum power heating and gas-stop Step No. Temperature C Ramp-time s Hold-time s Internal gas flow ml/min 1 100 10 20 300 2 650 60 40 300 3 1 900 0 5 0 4
42、2 700 1 3 50 Table 2 Pyro-coated tube with platform, with maximum power heating and gas-stop Step No. Temperature C Ramp-time s Hold-time s Internal gas flow ml/min 1 200 10 20 300 2 650 60 40 300 3 1 700 0 5 0 4 2 700 1 3 50 6.3 Determination 6.3.1 Measurement of blank solution Inject 20 l of the b
43、lank solution, prepared according to 6.1.4, into the graphite furnace. Intiate the temperature programme and record the absorption. 6.3.2 Measurement of standard solutions Inject 20 l of the three standard solutions, prepared according to 6.1.4, into the graphite furnace and record the absorptions.
44、6.3.3 Measurement of sample solutions Inject 20 l of the sample solution, prepared according to 6.1.3, into the graphite furnace. Initiate the temperature programme and record the absorption. ENISO12193:20044 7 Calculation and expression of results 7.1 Calculation 7.1.1 Measure the peak height on th
45、e recorder-chart or take the reading of the display or printer. 7.1.2 Draw a calibration curve by plotting the absorption of the three standard solutions (6.3.2), corrected for the blank (6.3.1), against their respective metal content. NOTE With the use of sophisticated equipment, autocalibration ca
46、n be applied. 7.1.3 Read the metal content of the sample from the calibration curve. 7.2 Expression of results Express the results as milligrams per kilogram (to two significant figures). 8 Precision 8.1 Interlaboratory test Details of an interlaboratory test on the precision of the method are summa
47、rized in Annex A. The values derived from this interlaboratory test may not be applicable to concentration ranges and matrices other than those given. The method has been tested with liquid oil (soyabean oil) and with solid fat (cocoa butter). 8.2 Repeatability limit The absolute difference between
48、two independent single test results, obtained with the same method on identical test material in the same laboratory by the same operator using the same equipment within a short interval of time, will not in more than 5 % of cases be greater than the repeatability limit (r) as calculated from the formulae in Table 3. Table 3 Repeatabi
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