1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationDD ISO/TS 23647:2010Vegetable fats and oils Determination of wax contentby gas chromatographyDD ISO/TS 23647:2010 DRAFT FOR DEVELOPMENTNational forewordThis Draft for Development
2、 is the UK implementation of ISO/TS23647:2010.This publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publicationsand is of a provisional nature. It should be applied on thisprovisional basis, so that information and experience of its pr
3、acticalapplication can be obtained.Comments arising from the use of this Draft for Developmentare requested so that UK experience can be reported to theinternational organization responsible for its conversion toan international standard. A review of this publication willbe initiated not later than
4、3 years after its publication by theinternational organization so that a decision can be taken on itsstatus. Notification of the start of the review period will be made inan announcement in the appropriate issue of Update Standards.According to the replies received by the end of the review period,th
5、e responsible BSI Committee will decide whether to support theconversion into an international Standard, to extend the life of theTechnical Specification or to withdraw it. Comments should be sentto the Secretary of the responsible BSI Technical Committee at BritishStandards House, 389 Chiswick High
6、 Road, London W4 4AL.The UK participation in its preparation was entrusted to TechnicalCommittee AW/307, Oil seeds, animal and vegetable fats and oilsand their by products.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purpo
7、rt to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2010ISBN 978 0 580 66083 2ICS 67.200.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This Draft for Development was published under the authority ofthe Sta
8、ndards Policy and Strategy Committee on 31 October 2010.Amendments issued since publicationDate Text affectedDD ISO/TS 23647:2010Reference numberISO/TS 23647:2010(E)ISO 2010TECHNICAL SPECIFICATION ISO/TS23647First edition2010-10-01Vegetable fats and oils Determination of wax content by gas chromatog
9、raphy Corps gras dorigine vgtale Dtermination de la teneur en cires par chromatographie en phase gazeuse DD ISO/TS 23647:2010ISO/TS 23647:2010(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not
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14、mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2010 All rights reservedDD ISO/TS 23647:2010ISO/TS 23647:2010(E) ISO 2010 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1 2 Normative references1 3 Terms and definitions .1 4 Principle1 5 Reagents and mate
15、rials 1 6 Apparatus.2 7 Sampling.3 8 Preparation of the test sample.3 9 Procedure.3 9.1 Preparation of silver nitrate-impregnated silica gel 60 .3 9.2 Column packing.3 9.3 Isolation of waxes3 9.4 Gas chromatographic determination of waxes 4 10 Precision.6 10.1 Results of interlaboratory test .6 10.2
16、 Repeatability 6 10.3 Reproducibility 6 11 Test report7 Annex A (informative) Chromatograms 8 Annex B (informative) Results of interlaboratory tests 12 Annex C (informative) Preparation of crystalline sunflower wax standard 13 Bibliography16 DD ISO/TS 23647:2010ISO/TS 23647:2010(E) iv ISO 2010 All r
17、ights reservedForeword 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 committees. Each member body interested in a subject
18、 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 International Electrotechnical Commission (IEC)
19、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 International Standards adopted by the technical committees
20、 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 documents, a technical committee may decide to pu
21、blish other types of 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 the parent committee casting a vote; an ISO Technical Speci
22、fication (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 in order to decide whether it will be confirmed for a fur
23、ther 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 be withdrawn. Attention is drawn to the possibility that
24、 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 23647 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 11, Animal and vegetable fats and oils. DD ISO/TS 23
25、647:2010ISO/TS 23647:2010(E) ISO 2010 All rights reserved vIntroduction Vegetable fats and oils consist predominantly of triacylglycerols, but they also contain small amounts of non-glyceridic substances often called minor components. The composition of these minor constituents (e.g. sterols, steryl
26、 esters, triterpene dialcohols, and waxes) provides highly characteristic information about the identity of the oils. Since the physical and chemical steps in the processing of vegetable fats and oils can cause alteration in their composition and content, analysis of these minor components can be co
27、nveniently applied to characterize the processing steps through which an oil was obtained. Waxes are natural compounds occurring in various vegetable oils and can easily crystallize at low temperatures resulting in cloudiness. Wax removal is very often a part of the vegetable oil-refining process (e
28、.g. sunflower, rice bran, corn oil) and its efficiency requires measurement. This Technical Specification does not cover the analysis of waxes of olive oil. With the exception of olive oil, there is currently no reliable official method to measure the wax content and composition of vegetable fats an
29、d oils. Cold tests give neither qualitative nor quantitative results; methods developed for olive oils are not applicable to seed oils and can cause a lot of problems in the interpretation of results. There is an industrial and commercial need for an International Standard which is applicable to cru
30、de, degummed, pre-dewaxed, winterized, and fully refined vegetable fats and oils. Waxes from different vegetable oils and fats are separated from triacylglycerols and from other non-glyceridic compounds containing double bonds by column chromatography using a mixed column packing consisting of silic
31、a gel and silica gel impregnated with AgNO3. The wax fraction is further analysed by capillary gas chromatography. The method also gives information about the total content of waxes and their composition. The information given by the method can be easily used to check oil quality and to track the ef
32、ficiency of the dewaxing process. DD ISO/TS 23647:2010DD ISO/TS 23647:2010TECHNICAL SPECIFICATION ISO/TS 23647:2010(E) ISO 2010 All rights reserved 1Vegetable fats and oils Determination of wax content by gas chromatography 1 Scope This Technical Specification specifies a gas chromatographic method
33、for determining the wax content of crude, degummed, neutralized, winterized, and fully refined vegetable oils, such as sunflower, soybean, rapeseed, corn, and rice bran oils. It is not applicable to olive oils or olive pomace oils. Waxes are esters of long chain fatty acids and fatty alcohols (havin
34、g C20or longer saturated carbon chain). The wax content is expressed in milligrams per kilogram of oil. 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
35、latest edition of the referenced document (including any amendments) applies. ISO 661, Animal and vegetable fats and oils Preparation of test sample 3 Terms and definitions For the purpose of this document, the following terms and definitions apply. 3.1 wax content mass fraction of those substances
36、in the sample, which are determined under the conditions specified in this Technical Specification NOTE The wax content is expressed in milligrams per kilogram of oil. 4 Principle The waxes are separated by column chromatography using a mixed column packing consisting of silica gel and silica gel im
37、pregnated with AgNO3. Determination of the waxes is carried out using capillary gas chromatography (GC), applying an internal standard, previously added to the oil. 5 Reagents and materials WARNING Attention is drawn to the regulations which specify the handling of dangerous matter. Technical, organ
38、izational and personal safety measures shall be followed. During the analysis, unless otherwise stated, use only reagents of recognized analytical grade suitable for HPLC column chromatography and distilled or demineralized water or water of equivalent purity. DD ISO/TS 23647:2010ISO/TS 23647:2010(E
39、) 2 ISO 2010 All rights reserved5.1 n-Hexane. 5.2 Dichloromethane. 5.3 n-Heptane. 5.4 Chloroform. 5.5 Silica gel 60, of particle size 0,063 mm to 0,200 mm (70 mesh to 230 mesh), such as Merck No. 1077341). 5.6 Silver nitrate (AgNO3). 5.7 Hexatriacontane2)(C36paraffin). 5.7.1 Internal standard soluti
40、on, mass concentration 0,1 mg/ml in n-heptane. 5.7.2 Standard for determination of response factor, mass concentration 1 mg/ml in n-heptane. 5.8 Standards for peak identification in the gas chromatogram, pure waxes3), e.g. C40, C44. 5.8.1 Standard for determination of response factor, stearyl steara
41、te or stearic acid stearyl ester (C36wax), mass concentration 1 mg/ml in chloroform. 5.9 Crystallized sunflower wax, prepared from winter cake or from crude sunflower oil using crystallization. For the preparation, see Annex C. 5.10 Cotton wool, surgical quality, non-absorbent. 6 Apparatus 6.1 Chrom
42、atographic column, made of glass, of internal diameter 30 mm and length 450 mm, equipped with a polytetrafluoroethylene (PTFE) tap. 6.2 Glass rod, about 600 mm in length. 6.3 Pasteur pipette, ISO 77124. 6.4 Vacuum rotary evaporator. 6.5 Round-bottomed flask, capacity 250 ml (to collect wax fraction)
43、. 6.6 Pear-shaped flask, capacity 25 ml (to collect the concentrated wax fraction). 6.7 Gas chromatograph, equipped with flame ionization detector, split/splitless injector and integrator or data acquisition system. 1) Merck No. 107734 is an example of a suitable product available commercially. This
44、 information is given for the convenience of users of this document and does not constitute an endorsement by ISO of this product. Equivalent products may be used if they can be shown to lead to the same results. 2) Hexatriacontane is available from Sigma-Aldrich with a purity of min. 99 % mass frac
45、tion. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of this supplier. 3) Pure waxes e.g. behenic acid stearyl ester (C40), stearic acid stearyl ester (C36) and behenic acid behenyl ester (C44) are available from Sigma-Aldrich, p
46、urity approximately 99 % mass fraction. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of this supplier. DD ISO/TS 23647:2010ISO/TS 23647:2010(E) ISO 2010 All rights reserved 36.8 Fused silica capillary column, length 25 m, inter
47、nal diameter 0,32 mm or preferably 0,20 mm, coated with dimethylpolysiloxane (e.g. HP-1 or OV-1 or equivalent), film thickness 0,11 m. 7 Sampling Sampling is not part of the method specified in this Technical Specification. A recommended sampling method is given in ISO 55551. It is important the lab
48、oratory receive a truly representative sample which has not been damaged or changed during transport or storage. 8 Preparation of the test sample Prepare the test sample in accordance with ISO 661. Heat the laboratory sample up to 130 C. Mix it so as to melt completely the crystallized waxes and rem
49、ove any moisture (a magnetic stirrer or microwave oven may be used). 9 Procedure 9.1 Preparation of silver nitrate-impregnated silica gel 60 Place 100 g of silica gel 60 (5.5) into a ceramic bowl. Pour a silver nitrate solution, containing 5 g AgNO3(5.6) dissolved in 240 ml water on to the silica gel and, after thorough mixing, make its surface flat. Put this suspension into a cold electric oven, heat to 170 C and activate the gel overnight. Allow to cool slowly to 50 C in the electric oven (in the dark). Keep this column packin
