1、BS ISO28198:2009ICS 67.200.10,NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDVegetable fats andoils Determinationof toluene insolublematterThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 31 October2009 BSI 2
2、009ISBN 978 0 580 64511 2Amendments/corrigenda issued since publicationDate CommentsBS ISO 28198:2009National forewordThis British Standard is the UK implementation of ISO 28198:2009.The UK participation in its preparation was entrusted to TechnicalCommittee AW/307, Oil seeds, animal and vegetable f
3、ats and oils andtheir by products.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Stand
4、ard cannot confer immunityfrom legal obligations.BS ISO 28198:2009Reference numberISO 28198:2009(E)ISO 2009INTERNATIONAL STANDARD ISO28198First edition2009-09-01Vegetable fats and oils Determination of toluene insoluble matter Corps gras dorigine vgtale Dtermination des matires insolubles dans le to
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9、g from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2009 All rights reservedBS ISO 28198
10、:2009ISO 28198:2009(E) ISO 2009 All rights reserved 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 committees.
11、 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 Interna
12、tional 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 International Stan
13、dards 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. Attention is drawn to the possibility that some of the elements of this document may be the subje
14、ct of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 28198 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 11, Animal and vegetable fats and oils. BS ISO 28198:2009BS ISO 28198:2009INTERNATIONAL STANDARD ISO 28198:200
15、9(E) ISO 2009 All rights reserved 1Vegetable fats and oils Determination of toluene insoluble matter 1 Scope This International Standard specifies a method for the determination of the content of toluene insoluble matter (TIM) in lecithin formulations, which indicates the presence of impurities such
16、 as protein, carbohydrate-containing extraction residues and other solid contaminants. This method is applicable to all types of vegetable lecithin. The purpose of the method is to enable the analysis of lecithin under several regulations. Lecithin Codex International Numbering System for Food Addit
17、ives (INS) No. 322 is a generally permitted additive and the determination of the TIM is part of many specifications. The purity requirement with regard to TIM content is based on the method specified. Toluene is the replacement for the carcinogenic benzene, which was used in older methods. 2 Terms
18、and definitions For the purposes of this International Standard, the following terms and definitions apply. 2.1 toluene insoluble matter TIM wTIMquantity of those substances that are insoluble in toluene under the conditions specified in this International Standard NOTE The toluene insoluble matter
19、content is expressed as a mass fraction in grams per 100 g. 3 Principle The sample is dissolved in toluene and filtered through a glass filter crucible of defined pore size (P 40). The insoluble residue is dried at (103 2) C and weighed. Glass filter crucibles with other pore sizes give different re
20、sults and shall not be used. 4 Reagents WARNING Attention is drawn to the regulations which specify the handling of hazardous substances. Technical, organizational and personal safety measures shall be followed. During the analysis, unless otherwise stated, use only reagents of recognized analytical
21、 grade and distilled or demineralized water or water of equivalent purity. 4.1 Toluene. BS ISO 28198:2009ISO 28198:2009(E) 2 ISO 2009 All rights reserved5 Apparatus 5.1 Glass filter crucible P 401), capacity 30 ml, pore size 16 m to 40 m. NOTE For the determination of TIM, the Joint FAO/WHO Expert C
22、ommittee on Food Additives (JECFA) recommends the use of a filter funnel G3 with a porosity of 16 m to 40 m (see Reference 5). According to ISO 47931, the porosity G3 (G2) is denominated as P 40 (P 100). IMPORTANT To clean glass filter crucibles, fill the ultrasonic bath with a phosphate-free alkali
23、ne cleaning solution2)for laboratory glassware with a volume fraction of 10 %. Put the glass filter crucibles into the ultrasonic bath for 30 min. Wash the glass filter crucibles with water, and if necessary repeat the cleaning step. Clean the glass filter crucibles in the laboratory cleaning machin
24、e. Use each glass filter crucible for a maximum of 10 analyses, as the pores become blocked and cannot be cleaned to a sufficient standard after repeated use. 5.2 Drying oven, capable of being maintained at (103 2) C. 5.3 Desiccator, with silica gel. 5.4 Glass beaker, of capacity 150 ml, tall form.
25、5.5 Filtering bottle. 5.6 Vacuum pump (for the filtration). 5.7 Analytical balance. 5.8 Measuring cylinder, of capacity 50 ml. 5.9 Glass rods of different sizes. 6 Sampling 6.1 General A representative sample should have been sent to the laboratory. It should not have been damaged or changed during
26、transport or storage. Sampling is not part of the method specified in this International Standard. A recommended sampling method is given in ISO 55552. 6.2 Preparation of the test sample Heat the test sample to max. 60 C, avoiding local overheating, and homogenize by powerful stirring. Record any sp
27、ecific treatments of the test sample (filtration, melting, etc.) in the test report. 1) Duranfilter crucible, porosity 3, diameter 36 mm, is an example of a suitable product available commercially. This information is given for the convenience of users of this International Standard and does not con
28、stitute an endorsement by ISO of this product. 2) ExtranMA03 phosphate-free is an example of a suitable product available commercially. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of this product. BS ISO 28198:20
29、09ISO 28198:2009(E) ISO 2009 All rights reserved 37 Procedure 7.1 Dry the glass filter crucible for 1 h at 103 C in the drying oven (5.2), allow to cool to room temperature in the desiccator (5.3) and weigh (5.7) to the nearest 0,1 mg. 7.2 From the test sample (6.2), accurately weigh (5.7) a test po
30、rtion of approximately 10,00 g to the nearest 0,01 g in the beaker (5.4). If the TIM is much higher than 0,3 % mass fraction, reduce the mass of the test portion, and record the details in the test report. 7.3 Dissolve the test portion in 100 ml of toluene while stirring with a glass rod. 7.4 Filter
31、 the solution through the glass filter crucible (5.1). Rinse the beaker twice with 25 ml of toluene each time and filter it just as before through the glass filter crucible. 7.5 Dry the filter crucible at 103 C in the drying oven (5.2) for 2 h, allow to cool to room temperature in the desiccator (5.
32、3) and then weigh (5.7) to the nearest 0,1 mg. CAUTION To avoid exposure to toluene, allow the toluene to evaporate at ambient temperature under local exhaust ventilation before transferring the crucible to the drying oven or use a drying oven in fume hood. 7.6 Then place the filter crucible in the
33、drying oven (5.2) for 30 min, allow to cool to room temperature in the desiccator (5.3) and weigh (5.7). The difference in mass from that measured in 7.5 shall not be more than 0,5 mg, otherwise repeat the drying procedure until a constant mass is obtained. If the mass increases, take the lower meas
34、ured value. 8 Calculation The toluene insoluble matter content, wTIM, in grams per 100 g, is given by: 21TIM0100mmwm= where m0is the mass, in grams, of the test portion; m1is the mass, in grams, of the crucible (7.1); m2is the mass, in grams, of the crucible plus the residue (7.5). Report the result
35、 to two decimal places. 9 Precision 9.1 Interlaboratory test Details of interlaboratory tests on the precision of the method are summarized in Annex A. The values derived from this interlaboratory test may not be applicable to concentration ranges and matrices other than those given. BS ISO 28198:20
36、09ISO 28198:2009(E) 4 ISO 2009 All rights reserved9.2 Repeatability The absolute difference between 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, shal
37、l in not more than 5 % of cases exceed the values of r given in Tables A.1 and A.2. 9.3 Reproducibility The absolute difference between two single test results, obtained with the same method on identical test material in different laboratories by different operators using different equipment, shall
38、in not more than 5 % of cases exceed the values of R given in Tables A.1 and A.2. 10 Test report The test report shall contain at least the following information: a) the test result(s) obtained; b) the test method used, together with reference to this International Standard; c) all the information r
39、equired for the complete identification of the sample; d) the sampling method used, if known; e) all operating details not specified in this International Standard, or regarded as optional, together with details of any incident that may have influenced the result(s). BS ISO 28198:2009ISO 28198:2009(
40、E) ISO 2009 All rights reserved 5Annex A (informative) Results of interlaboratory tests The precision of the method is the result of two interlaboratory studies organized by the Joint Committee for the Analysis of Fats, Oils, Fat Products, Related Products and Raw Materials (GA Fett) and the Interna
41、tional Lecithin and Phospholipid Society (ILPS). The studies were carried out in 1997 and 2007 on three and six samples, respectively. The test in 2007 was carried out with two glass filter crucibles with two different pore sizes (P 40 and P 100). The results for glass filter crucible P 40, evaluate
42、d according to ISO 5725-13and ISO 5725-24, are given in Tables A.1 and A.2. Table A.1 Summary of 1997 statistical results (glass filter crucible P 40) Crude lecithin sample No. 1 2 3 Number of participating laboratories, N 7 7 6 Number of laboratories retained after eliminating outliers, n 7 7 6 Num
43、ber of individual test results of all laboratories on each sample, nz14 14 12 Mean,TIM,w g/100 g 0,290 0,140 0,430Repeatability standard deviation, sr, mg/100 g 0,020 0,020 0,020Repeatability coefficient of variation, CV(r), % 8,4 16,5 4,4 Repeatability limit, r, g/100 g 0,070 0,070 0,050Reproducibi
44、lity standard deviation, sR, mg/100 g 0,150 0,090 0,100Reproducibility coefficient of variation, CV(R), % 50,8 63,4 22,7 Reproducibility limit, R, g/100 g 0,410 0,250 0,270Table A.2 Summary of 2007 statistical results (glass filter crucible P 40) Crude lecithin sample No. 1 2 3 4 5 6 Number of parti
45、cipating laboratories, N 14 14 12 14 14 13 Number of laboratories retained after eliminating outliers, n 13 11 11 13 11 10 Number of individual test results of all laboratories on each sample, nz26 22 22 26 22 20 Mean, TIM,w g/100 g 0,051 0,027 0,371 0,060 0,062 0,025Repeatability standard deviation
46、, sr, mg/100 g 0,007 0,004 0,057 0,0 0,012 0,007Repeatability coefficient of variation, CV(r), % 13,4 13,8 15,5 20,8 19,5 27,4 Repeatability limit, r, g/100 g 0,019 0,010 0,161 0,035 0,034 0,019Reproducibility standard deviation, sR, mg/100 g 0,034 0,025 0,163 0,044 0,026 0,021Reproducibility coeffi
47、cient of variation, CV(R), % 66,5 94,6 43,8 73,1 41,8 86,3 Reproducibility limit, R, g/100 g 0,095 0,071 0,455 0,124 0,072 0,059BS ISO 28198:2009ISO 28198:2009(E) 6 ISO 2009 All rights reservedA further filter crucible P 100 (G2) with a pore size of 40 m to 100 m was tested in the second interlabora
48、tory study. These results, evaluated according to ISO 5725-13and ISO 5725-24are given in Table A.3. Due to the wider pore size, the results are much lower and insufficient. Therefore a P 100 filter crucible is not recommended for use for the determination of TIM (see Clause 3, paragraph 2). Table A.
49、3 Summary of 2007 statistical results (glass filter crucible P 100) Crude lecithin sample No. 1 2 3 4 5 6 Number of participating laboratories, N 14 13 14 14 14 13 Number of laboratories retained after eliminating outliers, n 11 12 14 9 12 10 Number of individual test results of all laboratories on each sample, nz22 24 28 18 24 20 Mean, TIM,w g/100 g 0,012 0,008 0,165 0,010 0,016 0,009Repeatability standard deviation, sr, mg/100 g 0,004 0,003 0,025 0,0 0,005 0,000Repeatability coefficient of
