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1、DRAFT FOR DEVELOPMENT DD ISO/TS 17764-1:2002 Animal feeding stuffs Determination of the content of fatty acids Part 1: Preparation of methyl esters ICS 65.120 ? Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:28:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI D
2、D ISO/TS 17764-1:2002 This Draft for Development, having been prepared under the direction of the Consumer Products and Services Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 20 December 2002 BSI 20 December 2002 ISBN 0 580
3、40991 0 National foreword This Draft for Development reproduces verbatim ISO/TS 17764-1:2002. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development series of publications and is of a provisional nature because of the need to carry out collabora
4、tive trials to validate this method. It should be applied on this provisional basis, so that information and experience of its practical application may be obtained. Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the international o
5、rganization responsible for the Technical Specification. A review of this publication will be initiated not later than 3 years after its publication by the international organization so that a decision can be taken on its status at the end of its 3-year life. Notification of the start of the review
6、period will be made in an announcement in the appropriate issue of Update Standards. According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into an international standard, to extend the life of the Technical Spec
7、ification for another 3 years or to withdraw it. Comments should be sent in writing to the Secretary of BSI Technical Committee AW/10, Animal feeding stuffs, at British Standards House, 389 Chiswick High Road, London W4 4AL, giving the document reference and clause number and proposing, where possib
8、le, an appropriate revision of the text. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the secti
9、on entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. Summary of pages This document comprises a front cover, an inside front cover, the ISO/TS title page, pages ii and iii, a blank page, pages 1
10、to 6, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:28:02 GMT+00:
11、00 2006, Uncontrolled Copy, (c) BSI Reference number ISO/TS 17764-1:2002(E) TECHNICAL SPECIFICATION ISO/TS 17764-1 First edition 2002-11-01 Animal feeding stuffs Determination of the content of fatty acids Part 1: Preparation of methyl esters Aliments des animaux Dtermination de la teneur en acides
12、gras Partie 1: Prparation des esters mthyliques DD ISO/TS 177641:2002 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:28:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO/TS 17764-1:2002(E) DPlcsid Fremia ihTs PDF file may ctnoian emdebt dedyfepcaes. In ccaoc
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16、lbupctanoi may cudorper ebtu ro dezilina ni dey fomr yb ro nam y,snae lecetrinoc ro mecinahcal, inclidung tohpcoiypodna gn micrfoilm, wittuoh repmissii non writign from eitI rehSa Ot tsserdda eh ebolw or ISOs memreb i ydobn the cnuotrfo y ttseuqer ehe.r ISO cirypothg fofice saCe tsopale 65 eneG 1121
17、-HC 02 av leT. 4 + 10 947 22 1 11 xaF0 947 22 14 + 9 74 E-mail coirypthgiso.o gr We bwww.is.o gro Pulbisdehi n Switlrez dna ii ISO 2002 Allr ihgtsser edevr DD ISO/TS 177641:2002 ii Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:28:02 GMT+00:00 2006, Uncontro
18、lled Copy, (c) BSI ISO/TS 17764-1:2002(E) I SO 2002 All irhgts seredevr iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO
19、technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates clo
20、sely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are 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. Dra
21、ft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In other circumstances, particularly when there is an urgent market requirem
22、ent for such documents, a technical committee may decide to publish other types of normative document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50 % of th
23、e members of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed aft
24、er three years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an Internatio
25、nal Standard or be withdrawn. 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/TS 17764-1 was prepared by Technical Committee ISO/TC 34, Food prod
26、ucts, Subcommittee SC 10, Animal feeding stuffs. ISO/TS 17764 consists of the following parts, under the general title Animal feeding stuffs Determination of the content of fatty acids: Part 1: Preparation of methyl esters Part 2: Gas chromatographic method DD ISO/TS 177641:2002 iii Licensed Copy: L
27、ondon South Bank University, London South Bank University, Tue Dec 12 05:28:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:28:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI TECINHCAICEPS LFICATION IS/OTS -46771:12
28、002(E) I SO 2002 All irhgts seredevr 1 Animal feeding stuffs Determination of the content of fatty acids Part 1: Preparation of methyl esters 1 Scope ISO/TS 17764 specifies methods for the quantitative determination of individual fatty acids and of the sum of the fatty acids (elutable fatty acids).
29、This part of ISO/TS 17764 specifies two methods for preparing the methyl esters of fatty acids of animal and vegetable fats, oils and fatty acid mixtures for raw materials for compound animal feeds, and fatty acids originating from fat extracts of animal feeding stuffs, including fats and fatty acid
30、 mixtures containing butyric acid. The general method, the boron trifluoride (BF3) method, is concerned with the preparation of methyl esters of fatty acids with six or more C atoms, originating from fats, oils and free fatty acids. The KOH/HCl method is concerned with the preparation of methyl este
31、rs of fatty acids with four or more C atoms. This method can also be used for the quantitative determination of fatty acids with a chain length shorter than ten C atoms in free fatty acid mixtures. The methyl esters produced can be used for gas-liquid chromatography (GLC). NOTE 1 Unsaponifiable mate
32、rials are not removed and can, when present in considerable amounts, interfere with the chromatographic analysis. NOTE 2 ISO/TS 17764-2 describes the application of gas chromatography with capillary columns and flame ionization detection for the determination of the content of fatty acids in a fat b
33、y making use of the methyl esters of the fatty acids obtained in accordance with the methods specified in this part of ISO/TS 17764. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies.
34、 For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 661:1989, Animal and vegetable fats and oils Preparation of test sample ISO 3696:1987, Water for analytical laboratory use Specification and test methods ISO 6492:1999, Animal feeding stuff
35、s Determination of fat content DD ISO/TS 177641:2002 1 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:28:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO/TS 17764-1:2002(E) 2 I SO 2002 All irhgts seredevr 3 Fat extraction 3.1 General Extract the fat for det
36、ermination of the content of the saponifiable fatty acids in an animal feeding stuff or mixed feed in accordance with the category of the feeding stuff, as described in ISO 6492:1999, with the following amendments. 3.2 Samples of category A Perform a fat extraction in accordance with 9.5.1 of ISO 64
37、92:1999. Evaporate the solvent with a rotating evaporator in a water bath at a temperature of not more than 40 C. Then dry the residue for 2 h in a vacuum drying oven at 40 C 2 C. 3.3 Samples of category B Extract the fat in two steps. For the first step, proceed in accordance with 9.5.1 of ISO 6492
38、:1999, treating the test portion as described in 9.3 of ISO 6492:1999 as a sample of category A. Collect the fat extract in a dry flask. Allow the solvent to evaporate from the residue by exposing the thimble to the air. Perform a hydrolysis of the residue in accordance with 9.4 of ISO 6492:1999. Af
39、ter hydrolysis, dry the residue in an extraction thimble for 60 min in a vacuum drying oven at 40 C 2 C. Extract the residue according to 9.5.1 of ISO 6492:1999. Add the fat extract to the first extract. Evaporate the solvent with a rotating evaporator in a water bath at a temperature of not more th
40、an 40 C and dry the residue for 2 h in a vacuum drying oven at 40 C 2 C. 4 Preparation of test sample of fat or fat extract If the fat sample or the fat extract is not completely molten, heat the sample to a temperature of not more than 10 C above the melting temperature. See ISO 661. 5 Method for t
41、he preparation of methyl esters of fatty acids with six or more C atoms (BF3 method) 5.1 Principle The glycerides are saponified with methanolic sodium hydroxide. The soaps are converted to methyl esters by reaction with a boron trifluoride/methanol complex. 5.2 Reagents Use only reagents and solven
42、ts of recognized analytical grade. 5.2.1 Water, complying with at least grade 3 in accordance with ISO 3696:1987. 5.2.2 Heptadecanoic acid (internal standard), of purity at least 99 %. DD ISO/TS 177641:2002 2 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:28
43、:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO/TS 17764-1:2002(E) I SO 2002 All irhgts seredevr 3 5.2.3 Sodium hydroxide, methanolic solution, c(NaOH) 0,5 mol/l. Dissolve 2 g of sodium hydroxide in 100 ml of methanol containing not more than 0,5 % (mass fraction) of water. If the solution has to
44、 be stored for a considerable time, a small amount of white precipitate of sodium carbonate can form; this has no effect on the preparation of the methyl esters. Instead of sodium hydroxide, a methanolic solution of potassium hydroxide with the same concentration may be used. 5.2.4 Boron trifluoride
45、 (BF3), methanolic solution, 10 % to 15 % (mass fraction). WARNING Boron trifluoride is poisonous. For this reason, it is not recommended that the analyst prepare the methanolic solution of boron trifluoride from methanol and boron trifluoride. Solutions are available commercially. In gas chromatogr
46、aphic analysis of the methyl esters, certain reagents can give rise to peaks which interfere with the analysis. In particular, BF3 solutions can cause peaks in the area of the methyl esters of fatty acids with 20 or 22 C atoms. It is recommended to check the reagents by preparing the methyl ester of
47、 oleic acid followed by a gas chromatographic analysis. Reagents shall not give rise to peaks which interfere with the gas chromatographic analysis of the fatty acid methyl esters. 5.2.5 n-Hexane or n-heptane. 5.2.6 Sodium chloride, saturated aqueous solution. 5.2.7 Sodium sulfate, anhydrous. 5.3 Ap
48、paratus Usual laboratory equipment and, in particular, the following. 5.3.1 Round-bottom flask, of capacity 50 ml, with ground neck and fitted with a ground glass stopper. 5.3.2 Boiling aid, fat-free. 5.3.3 Reflux condenser, of effective length 20 cm to 30 cm, with a ground joint to fit the flask. 5
49、.3.4 Graduated pipette, of capacity at least 10 ml and fitted with a rubber bulb, or an automatic pipette. 5.3.5 Vials with screw caps. 5.4 Procedure 5.4.1 General Because of the toxic character of boron trifluoride, the methylation is best performed under a ventilated hood. It is essential to wash all glassware with water immediately after use. If the fatty acids contain more than two double bonds, it is recommended to remove the air from t