1、BRITISH STANDARDBS ISO 22662:2007Milk and milk products Determination of lactose content by high-performance liquid chromatography (Reference method) ICS 67.100.01g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48
2、g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS ISO 22662:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2008 BSI 2008ISBN 978 0 580 56173 3National forewordThis British Standard is the UK implementation of ISO
3、 22662:2007.The UK participation in its preparation was entrusted to Technical Committee AW/5, Chemical analysis of milk and milk products.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary
4、provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate CommentsReference numbersISO 22662:2007(E)IDF 198:2007(E)INTERNATIONAL STANDARD ISO22662IDF1
5、98First edition2007-09-15Milk and milk products Determination of lactose content by high-performance liquid chromatography (Reference method) Lait et produits laitiers Dtermination de la teneur en lactose par chromatographie liquide haute performance (Mthode de rfrence) BS ISO 22662:2007IDF 198:2007
6、ii iiiContents Page Foreword iv Foreword. v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle. 1 5 Reagents 1 6 Apparatus 2 7 Sampling 3 8 Preparation of test sample. 3 9 Procedure 4 9.1 Preparation of the standard solution 4 9.2 Preparation of test portion. 4 9.3 Prepara
7、tion of filtrate 4 9.4 HPLC determination . 5 10 Calculation and expression of results 6 10.1 Calculation. 6 10.2 Expression of results . 6 11 Precision 7 11.1 Interlaboratory test . 7 11.2 Repeatability 7 11.3 Reproducibility 7 12 Test report . 7 Annex A (informative) Results of interlaboratory tes
8、t 8 Bibliography . 10 BS ISO 22662:2007IDF 198:2007iv 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 technical committees.
9、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 Internat
10、ional 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 Stand
11、ards 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 subjec
12、t of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 22662IDF 198 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF). It is being published jointly b
13、y ISO and IDF. BS ISO 22662:2007IDF 198:2007vForeword IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committee in every member country. Every National Committee has the right to be represented on the IDF Standing Committees carrying out the tec
14、hnical work. IDF collaborates with ISO in the development of standard methods of analysis and sampling for milk and milk products. Draft International Standards adopted by the Action Teams and Standing Committees are circulated to the National Committees for voting. Publication as an International S
15、tandard requires approval by at least 50 % of the IDF National Committees casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. IDF shall not be held responsible for identifying any or all such patent rights. ISO 22662ID
16、F 198 was prepared by the International Dairy Federation (IDF) and Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products. It is being published jointly by IDF and ISO. All work was carried out by the Joint ISO-IDF Action Team on Lactose w is the width of the lactose
17、 peak, equivalent to time difference in minutes, at 50 % of its height. When the theoretical plate count decreases by more than 25 % compared to the original measurement, a replacement of the column is recommended. NOTE In most cases, a used column performing with low efficiency can be restored to i
18、ts original form by back washing with an appropriate regenerating solvent described in the manufacturers documentation. BS ISO 22662:2007IDF 198:20076 Key M D(+)-melezitose L -lactose tRretention time U potential difference Figure 1 Example of a chromatogram from a raw milk sample containing the int
19、ernal standard 10 Calculation and expression of results 10.1 Calculation A computer performs the calculations as follows: First, the software (6.8) generates a curve by plotting the response ratio of the lactose standard peak area, As, to that of the internal standard, Ais, multiplied by the interna
20、l standard concentration, cis, i.e. (As/Ais) cis, against lactose concentration, cl. The curve fit is linear through the origin. To quantify an unknown test sample, the software divides the concentration derived from the calibration curve by the mass of the test sample to calculate the anhydrous lac
21、tose mass fraction expressed as a percentage. 10.2 Expression of results Express the test results to three decimal places. BS ISO 22662:2007IDF 198:2007711 Precision 11.1 Interlaboratory test Details of the interlaboratory test on the precision of the method are summarized in Annex A. The values der
22、ived from this interlaboratory test may not be applicable to concentration ranges and matrices other than those given. 11.2 Repeatability The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the same
23、operator using the same equipment within a short interval of time, will in not more than 5 % of cases be greater than: a) for fluid milk: 0,06 %; b) for cream: 0,06 %; c) for milk powder: 0,37 %. 11.3 Reproducibility The absolute difference between two single test results, obtained using the same me
24、thod on identical test material in different laboratories with different operators using different equipment, will in not more than 5 % of cases be greater than: a) for fluid milk: 0,13 %; b) for cream: 0,38 %; c) for milk powder: 2,94 %. 12 Test report The test report shall specify: a) all the info
25、rmation required for the complete identification of the sample; b) the sample method used, if known; c) the method used, with reference to this International Standard; d) all operating details not specified in this International Standard, or regarded as optional, together with details of any inciden
26、t which may have influenced the results; e) the test result(s) obtained and, if the repeatability has been checked, the final quoted result obtained. BS ISO 22662:2007IDF 198:20078 Annex A (informative) Results of interlaboratory test An international collaborative test involving eight laboratories
27、from five countries was carried out on 18 samples (six of fluid milk, six of cream and six of milk powder), all obtained from three dairy plants in Qubec, Canada. The test was organized by the Programme des Analyses des Troupeaux Laitiers du Qubec. The results obtained were subjected to statistical
28、analysis in accordance with ISO 5725-1 and ISO 5725-2 to give the precision data shown in Tables A.1 to A.3. All values expressed as percentages, except coefficients of variation, are mass fractions. Table A.1 Fluid milk results Test sample 1 2 3 4 5 6 MeanNo. of participating laboratories after eli
29、minating outliers 8 8 7 8 7 8 Mean lactose mass fraction, % 4,530 4,466 4,718 4,644 4,364 4,551 Repeatability standard deviation, sr, %0,025 0,023 0,017 0,035 0,011 0,018 0,022 Repeatability limit, r = 2,8sr, % 0,071 0,065 0,047 0,098 0,031 0,051 0,061 Coefficient of variation of repeatability, % 0,
30、559 0,523 0,360 0,751 0,258 0,397 0,474 Reproducibility standard deviation, sR, % 0,042 0,056 0,044 0,046 0,030 0,058 0,046 Reproducibility limit, R = 2,8sR, % 0,118 0,156 0,123 0,128 0,085 0,162 0,129 Coefficient of variation of reproducibility, % 0,931 1,249 0,929 0,986 0,692 1,273 1,010 Table A.2
31、 Cream results Test sample 1 2 3 4 5 6 Mean No. of participating laboratories after eliminating outliers 8 8 7 8 6 6 Mean lactose mass fraction, % 1,461 3,822 3,686 2,886 3,256 3,103 Repeatability standard deviation, sr, % 0,030 0,015 0,025 0,032 0,009 0,007 0,020 Repeatability limit, r = 2,8sr, % 0
32、,084 0,041 0,069 0,090 0,026 0,020 0,055 Coefficient of variation of repeatability, % 2,066 0,381 0,672 1,117 0,283 0,224 0,790 Reproducibility standard deviation, sR, % 0,171 0,108 0,136 0,118 0,134 0,136 0,134 Reproducibility limit, R = 2,8sR, % 0,479 0,302 0,380 0,331 0,375 0,382 0,375 Coefficien
33、t of variation of reproducibility, % 11,721 2,824 3,686 4,090 4,113 4,397 5,139 BS ISO 22662:2007IDF 198:20079Table A.3 Milk powder results Test sample 1 2 3 4 5 6 MeanNo. of participating laboratories after eliminating outliersa6 7 7 6 6 7 Mean lactose mass fraction, % 48,721 36,348 35,087 52,306 4
34、6,460 48,171 Repeatability standard deviation, sr, % 0,110 0,040 0,111 0,260 0,157 0,118 0,133 Repeatability limit, r = 2,8sr, % 0,308 0,111 0,312 0,729 0,440 0,331 0,372 Coefficient of variation of repeatability, % 0,226 0,109 0,318 0,497 0,339 0,245 0,289 Reproducibility standard deviation, sR, %
35、1,130 0,801 0,773 0,709 1,461 1,419 1,049 Reproducibility limit, R = 2,8sR, % 3,165 2,241 2,1663 1,986 4,091 3,974 2,937 Coefficient of variation of reproducibility, % 2,322 2,202 2,202 1,356 3,145 2,946 2,362 aOnly seven laboratories provided results for the tests on milk powder. BS ISO 22662:2007I
36、DF 198:200710 Bibliography 1 ISO 707|IDF 50, Milk and milk products Guidance on sampling 2 ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions 3 ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results Pa
37、rt 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method 4 BIGGS D.A., SZIJARTO, L. Method for routine determination of lactose in milk, J. Dairy Sci. 1963, 46, pp. 1196-200 5 HARVEY, J. A high performance liquid chromatography method for lactose
38、 determination in milk. Austral. J. Dairy Technol. 1988, 43, pp. 1920 6 BRONS, C., OLIEMAN, C. Study of the high-performance liquid chromatographic separation of reducing sugars, applied to the determination of lactose in milk. J. Chromatogr. 1983, 259, pp. 7986 7 KOOPS, J., OLIEMAN, C. Routine test
39、ing of farm milk with the Milko-Scan 203.3. Comparative evaluation of polarimetry, HPLC, enzymatic assay and reductometry for the determination of lactose. Calibration for infra-red analysis of lactose. Calculation of total solids from infra-red measurements, Neth. Milk Dairy J. 1985, 39, pp. 89106
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