1、DRAFT FOR DEVELOPMENTDD CEN ISO/TS 17764-2:2006Animal feeding stuffs Determination of the content of fatty acids Part 2: Gas chromatographic methodICS 65.120g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55
2、g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58DD CEN ISO/TS 17764-2:2006This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 28 February 2007 BSI 2007ISBN 978 0 580 50176 0National forewordThis Draft for Development was published b
3、y BSI. It is the UK implementation of CEN ISO/TS 17764-2:2006.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. It should be applied on this provisional basis, so that information and ex
4、perience of its practical application can be obtained.Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the European organization responsible for its conversion to a European standard. A review of this publication will be initiated not
5、 later than 3 years after its publication by the European organization so that a decision can be taken on its status. Notification of the start of the review 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
6、 period, the responsible BSI Committee will decide whether to support the conversion into a European Standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent to the Secretary of the responsible BSI Technical Committee at British Standards House, 389 Chis
7、wick High Road, London W4 4AL.The UK participation in its preparation was entrusted to Technical Committee AW/10, Animal feeding stuffs.A list of organizations represented on AW/10 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions o
8、f a contract. Users are responsible for its correct application.Amendments issued since publicationAmd. No. Date CommentsTECHNICAL SPECIFICATIONSPCIFICATION TECHNIQUETECHNISCHE SPEZIFIKATIONCEN ISO/TS 17764-2October 2006ICS 65.120English VersionAnimal feeding stuffs - Determination of the content of
9、 fattyacids - Part 2: Gas chromatographic method (ISO/TS 17764-2:2002)Aliments des animaux - Dtermination de la teneur enacides gras - Partie 2: Mthode par chromatographie enphase gazeuse (ISO/TS 17764-2:2002)Futtermittel - Bestimmung des Gehaltes an Fettsuren -Teil 2: Gaschromatographisches Verfahr
10、en (ISO/TS 17764-2:2002)This Technical Specification (CEN/TS) was approved by CEN on 13 February 2006 for provisional application.The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit theircomments, particularly on t
11、he question whether the CEN/TS can be converted into a European Standard.CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS availablepromptly at national level in an appropriate form. It is permissible to keep conflicting national st
12、andards in force (in parallel to the CEN/TS)until the final decision about the possible conversion of the CEN/TS into an EN is reached.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Irela
13、nd, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B
14、-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. CEN ISO/TS 17764-2:2006: EForeword This document (CEN ISO/TS 17764-2:2006) has been prepared by Technical Committee CEN/TC 327 “Animal feeding stuffs - Methods of sampl
15、ing and analysis“, the secretariat of which is held by NEN, in collaboration with Technical Committee ISO/TC 34 “Agricultural food products“. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this CEN Technical Sp
16、ecification: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. CEN IS
17、O/TS 17764-2:2006Reference numberISO/TS 17764-2:2002(E)TECHNICAL SPECIFICATION ISO/TS17764-2First edition2002-11-01Animal feeding stuffs Determination of the content of fatty acids Part 2: Gas chromatographic method Aliments des animaux Dtermination de la teneur en acides gras Partie 2: Mthode par c
18、hromatographie en phase gazeuse CEN ISO/TS 17764-2:2006ii iiiForeword 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 technical commi
19、ttees. 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 closely with the I
20、nternational 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. Draft Internationa
21、l 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 requirement for such do
22、cuments, 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 the members of th
23、e 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 after three years
24、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 International Standard or
25、 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 17764-2 was prepared by Technical Committee ISO/TC 34, Food products, Subcommit
26、tee 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 CEN ISO/TS 17764-2:2006blank1Animal feeding stuffs Determ
27、ination of the content of fatty acids Part 2: Gas chromatographic method 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). This part of ISO/TS 17764 specifies the application of gas chromatogr
28、aphy with capillary columns and flame ionization detection for the determination of the quantitative content of fatty acids in a fat by making use of the methyl esters of the fatty acids obtained in accordance with the method specified in ISO/TS 17764-1. This part of ISO/TS 17764 is applicable to th
29、e investigation of animal and vegetable fats, oils and fatty acid mixtures for incorporation in animal feeding stuffs and fat extracts of animal feeding stuffs and raw materials for compound animal feeds, including fats and fatty acid mixtures containing butyric acid. This method is not applicable t
30、o polymerized fatty acids. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
31、 ISO 3696:1987, Water for analytical laboratory use Specification and test methods ISO/TS 17764-1, Animal feeding stuffs Determination of the content of fatty acids Part 1: Preparation of methyl esters 3 Terms and definitions For the purposes of this document, the following terms and definitions app
32、ly. 3.1 fatty acid content mass fraction of the fatty acids in the test portion of oil, fat, fat extract, free fatty acids or soaps NOTE The fatty acid content is expressed in grams per kilogram. 3.2 content of elutable material mass fraction of the sum of all the fatty acids elutable using a gas ch
33、romatographic column as described in this part of ISO/TS 17764 CEN ISO/TS 17764-2:20062 4 Principle The methyl esters prepared from fatty acids in accordance with ISO/TS 17764-1 are separated with gas-liquid chromatography, making use of a capillary column. The peaks in the chromatogram are defined
34、with the help of a reference sample of known composition and are quantified by means of an internal standard. 5 Reagents Use only reagents and solvents of recognized analytical grade. 5.1 Water, complying with at least grade 3 in accordance with ISO 3696:1087. 5.2 n-Hexane or n-heptane. 5.3 n-Pentan
35、e. 5.4 Reference sample: an oil or fat sample with exactly known fatty acid pattern, or a mixture of reference fatty acid methyl ester materials or reference fatty acids materials. NOTE If the BF3method for esterification is used, a mixture of reference fatty acid methyl esters cannot be used for ca
36、libration or correction factors for fatty acids with a chain length of less than 10 carbon atoms, because of possible solubility of the methyl esters in the water phase. 6 Apparatus Usual laboratory equipment and, in particular, the following. 6.1 Gas chromatograph, comprising a capillary column and
37、 an injection system specially designed for use with such columns. It may be of the split or the split-less type or a cold on-column injector. However, a warm split-less injector is not suitable for the analysis of milk fats due to overlap of the solvent peak with the butyric acid peak. 6.2 Column,
38、constructed of inert material (fused silica or glass) with a stationary phase preferable chemically bonded to the wall of the column. Column dimensions and film thickness are important factors in determining the separation efficiency and capacity of the column. A resolution of at least 1,25 for the
39、fatty acids C16:0 and C16:1, and C18:0 and C18:1 should be accomplished. NOTE In most cases a moderately polar phase will suit. In special cases, for instance for the separation of cis-trans-isomers and/or positional isomers, or if one must be sure that no peaks coincide, a more polar phase is warra
40、nted. The desirable effectiveness and capacity of the column should also be considered for column dimensions and film thickness. Moderately polar phases are, for instance, various esters of poly(ethylene glycol). More polar phases are often of the cyano-propyl-polysiloxane type. 6.3 Injection system
41、, for manual injection, with a capacity of at most 10 l, and graduated in 0,1 l divisions, suited for the injector (6.2), or an automatic injection system. NOTE The use of an automatic system is preferable and can improve repeatability and reproducibility. 6.4 Signal evaluation apparatus: an electro
42、nic system fitted with a recorder to transform the detector signal to a chromatogram (an integrator or a data station). CEN ISO/TS 17764-2:200637 Procedure 7.1 Preparation of methyl esters Prepare the methyl esters of the fatty acids of the test portion and the reference sample (5.4) in accordance w
43、ith ISO/TS 17764-1. 7.2 Selection of optimum operating conditions Optimize the equipment in accordance with the instructions given by the manufacturer. Optimize the flow of carrier gas in accordance with the recommendations of the column manufacturer for the chosen column and the carrier gas. Mainta
44、in a detector temperature of 20 C to 50 C above the highest temperature of the column in a programmed heating, but at least at 150 C. The injector temperature depends on the type of the injector; follow the instructions given in the equipment manual. When using a split injector, set the split ratio
45、between 1:30 and 1:100. 7.3 Analysis 7.3.1 Dissolve the fatty acid methyl esters of the test portion and the test portion with added internal standard in n-hexane (5.2) to a content of 1 % (mass fraction) when using a split injector, or 0,05 % (mass fraction) in the case of a split-less injector or
46、a cold on-column injector. Prepare a solution of the fatty acid methyl esters of the reference sample (7.1) in n-hexane with a comparable concentration. Inject separately 0,1 l to 1 l of the test sample, the test sample with internal standard, and when necessary the reference sample. When using cold
47、 on-column injection, the use of n-pentane as solvent is necessary for a good separation of the fatty acid methyl esters with a chain length of less than 10 carbon atoms. Dissolve the methyl esters of the fatty acids in the test portions and the reference sample in the same solvent. 7.3.2 Select a t
48、emperature programme depending on the fatty acid composition, allowing an effective resolution in the shortest possible time. Take into account the criteria mentioned in 6.3. Programme the oven temperature starting from 60 C if the sample contains fatty acids with a chain length shorter than 12 carb
49、on atoms. If necessary, progress isothermally after the highest temperature in the programme has been reached until all components have been eluted. When using a cold on-column injector, start with an oven temperature of not more than 10 C higher than the boiling point of the solvent at the prevailing pressure (50 C for n-pentane). Start the temperature programme immediately after the injection. Follow the manufacturers instructions. 8 Peak identification Identify the methyl ester peaks of the test portion according to the retention times
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