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1、BRITISH STANDARD CONFIRMED JUNE 1993 BS 684-2.44: 1984 ISO 6464:1983 Methods of analysis of Fats and fatty oils Part 2: Other methods Section 2.44 Determination of gallates ISO title: Animal and vegetable fats and oils Determination of gallates content Molecular absorption spectrometric method IMPOR
2、TANT NOTE. It is essential that BS 684-0, which is published separately, be read in conjunction with this Section. UDC 665.1.014:543.42:547.587.26 Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.44:1984 This British Standard, having
3、 been prepared under the direction of the Food and Agriculture Standards Committee, was published under the authority of the Board of BSI and comes into effect on 31 May 1984 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference FAC/18 Draft for comment 82
4、/54516 DC ISBN 0 580 13864 X National foreword This Section of BS 684 has been prepared under the direction of the Food and Agriculture Standards Committee. It is identical with ISO 6464:1983 “Animal and vegetable fats and oils Determination of gallates content Molecular absorption spectrometric met
5、hod” published by the International Organization for Standardization (ISO). Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those
6、 used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standa
7、rd, they should be read as “British Standard”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligat
8、ions. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the
9、 inside front cover. Cross-references International StandardsCorresponding British Standards ISO 661:1980BS 684 Methods of analysis of fats and fatty oils Part 0:1982 General introduction, Appendix B (Identical) ISO 5555:1983BS 627:1982 Methods for sampling animal and vegetable fats and oils (Techni
10、cally equivalent) ISO 5558:1982BS 684 Methods of analysis of fats and fatty oils Section 2.33:1983 Detection and identification of antioxidants (Identical) Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:11 GMT+00:00 2006
11、, Uncontrolled Copy, (c) BSI BS 684-2.44:1984 BSI 10-1999i Contents Page National forewordInside front cover 1Scope and field of application1 2References1 3Principle1 4Reagents1 5Apparatus1 6Sampling1 7Detection1 8Procedure1 9Expression of results2 10Test report3 Publications referred toInside back
12、cover Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.44:1984 BSI 10-19991 1 Scope and field of application This Int
13、ernational Standard specifies a molecular absorption spectrometric method permitting the separate determination of propyl-, octyl- and dodecyl gallates, used as antioxidants in animal and vegetable fats and oils. In the presence of other antioxidants, which can be detected and identified by the meth
14、od specified in ISO 5558, care should be taken in the interpretation of the results, because such other antioxidants may interfere and give high results for the gallates content. NOTEIt has been shown that a) for contents of each of the three gallates of 200 mg/kg, the following antioxidants, at con
15、tents up to 50 mg/kg, have a negligible influence on the determination of propyl and octyl gallates: lonox 100, nordihydroguairetic acid (NDGA), tertiobutylhydroquinone (TBHQ), 2,4,5-trihydroxybutyrophenone (THBP); b) butylhydroxyanisole presents a risk of interference. If there is interference, a d
16、isplacement of the peak corresponding to the maximum absorbance will be observed. 2 References ISO 661, Animal and vegetable fats and oils Preparation of test sample. ISO 5555, Animal and vegetable fats and oils Sampling. ISO 5558, Animal and vegetable fats and oils Detection and identification of a
17、ntioxidants Thin layer chromatographic method. 3 Principle Selective extraction of each gallate from the test portion by means of appropriate solvents and determination by ultraviolet spectrometric measurement, in the following order: propyl gallate; octyl gallate; dodecyl gallate. 4 Reagents All re
18、agents shall be of recognized analytical quality and the water used shall be distilled water or water of at least equivalent purity. 4.1 n-hexane 4.2 Ammonium acetate, 10 g/l solution. 4.3 Acetonitrile, 32 % (V/V) solution, of such quality that the percentage transmission is at least 40 % at 270 nm.
19、 WARNING Acetonitrile is very flammable, and toxic by inhalation, skin contact and ingestion. 4.4 Acetonitrile, 46 % (V/V) solution, of such quality that the percentage transmission is at least 40 % at 270 nm. 5 Apparatus Usual laboratory equipment, and 5.1 Conical flask, of capacity 500 ml. 5.2 Sep
20、arating funnel, of capacity 500 ml. 5.3 Beakers, of capacity 150 ml. 5.4 Pipettes, of capacity 100 ml, or measuring cylinders, of capacity 100 ml. 5.5 Spectrometer, with cells of optical path length 10 mm, suitable for making measurements in the ultraviolet region. 6 Sampling Take the laboratory sam
21、ple in accordance with ISO 5555. 7 Detection See ISO 5558. 8 Procedure 8.1 Preparation of the test sample Prepare the test sample in accordance with ISO 661. 8.2 Test portion Weigh, to the nearest 0,1 g, 20 g of the test sample into the conical flask (5.1). 8.3 Determination Dissolve the test portio
22、n in 250 ml of the n-hexane (4.1) and pour the solution quantitatively into the separating funnel (5.2), rinsing the flask with a little n-hexane. Proceed with the extraction and determination of gallates, which is carried out in the order: propyl gallate, octyl gallate and dodecyl gallate. 8.3.1 De
23、termination of propyl gallate 8.3.1.1 Extraction Add to the contents of the separating funnel 100 ml of the ammonium acetate solution (4.2), measured by means of a pipette or a measuring cylinder (5.4). Shake, allow the phases to separate and collect the aqueous phase in a beaker (5.3). Carry out on
24、e or, at most, two supplementary extractions on the hexane phase, using, each time, 100 ml of the ammonium acetate solution (4.2) and collecting the extracts separately in beakers (5.3). Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684
25、-2.44:1984 2 BSI 10-1999 8.3.1.2 Determination Measure the absorbance at 272 nm and at 330 nm of each extract, in cells of optical path length 10 mm, by means of the spectrometer (5.5), using the ammonium acetate solution as the reference liquid. Calculate the differences between the absorbances mea
26、sured. Let A1, A2 and, if appropriate, A3 be the values obtained. Ensure that the extraction of propyl gallate is complete, and that no extraction of another gallate has occurred, by verifying that the difference between the absorbances measured at 272 nm and 330 nm for the last extract is less than
27、 0,05. 8.3.2 Determination of octyl gallate 8.3.2.1 Extraction Add to the hexane phase in the separating funnel, after extraction of the propyl gallate, 100 ml of the 32 % (V/V) acetonitrile solution (4.3), measured by means of a pipette or a measuring cylinder (5.4). Shake moderately, allow the pha
28、ses to separate and collect the aqueous phase in a beaker (5.3). Carry out one or, at most, two supplementary extractions, using, each time, 100 ml of the 32 % (V/V) acetonitrile solution (4.3) and collecting the extracts separately in beakers (5.3). 8.3.2.2 Determination Measure the absorbance at 2
29、72 nm and at 330 nm of each extract, in cells of optical path length 10 mm, by means of the spectrometer (5.5), using the 32 % (V/V) acetonitrile solution (4.3) as the reference liquid. Calculate the differences between the absorbances measured. Let B1, B2 and, if appropriate, B3 be the values obtai
30、ned. Ensure that the extraction of octyl gallate is complete, and that no extraction of another gallate has occurred, by verifying that the difference between the absorbances measured at 272 nm and 330 nm for the last extract is less than 0,05. 8.3.3 Determination of dodecyl gallate 8.3.3.1 Extracti
31、on Add to the hexane phase in the separating funnel, after extraction of the propyl and octyl gallates, 100 ml of the 46 % (V/V) acetonitrile solution (4.4), measured by means of a pipette or a measuring cylinder (5.4). Shake moderately to avoid emulsions, allow the phases to separate and collect th
32、e aqueous phase in a beaker (5.3). Carry out one or, at most, two supplementary extractions, using, each time, 100 ml of the 46 % (V/V) acetonitrile solution (4.4) and collecting the extracts separately in beakers (5.3). 8.3.3.2 Determination Measure the absorbances at 272 nm and at 330 nm of each e
33、xtract, in cells of optical path length 10 mm, by means of the spectrometer (5.5), using the 46 % (V/V) acetonitrile solution (4.4) as the reference liquid. Calculate the difference between the absorbances measured. Let C1, C2 and, if appropriate, C3 be the values obtained. Ensure that the extractio
34、n of the dodecyl gallate is complete by verifying that the difference between the absorbances measured at 272 nm and 330 nm for the last extract is less than 0,1. 9 Expression of results 9.1 The propyl gallate content, expressed in milligrams per kilogram (ppm) of product, is equal to where A1, A2 a
35、nd A3are the differences between the absorbances measured at 272 nm and at 330 nm for each extract (see 8.3.1.2); mis the mass, in grams, of the test portion (8.2). 9.2 The octyl gallate content, expressed in milligrams per kilogram (ppm) of product, is equal to where B1, B2 and B3are the difference
36、s between the absorbances measured at 272 nm and at 330 nm for each extract (see 8.3.2.2); mis the mass, in grams, of the test portion (8.2). 9.3 The dodecyl gallate content, expressed in milligrams per kilogram (ppm) of product, is equal to where C1, C2 and C3are the differences between the absorba
37、nces measured at 272 nm and at 330 nm for each extract (see 8.3.3.2); mis the mass, in grams, of the test portion (8.2). A1A2A3+()106 430m - - B1B2B3+()106 370m - C1C2C3+()106 280m - Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.4
38、4:1984 BSI 10-19993 10 Test report The test report shall show the method used and the results obtained. It shall also mention any operating conditions not specified in this International Standard, or regarded as optional, as well as any incidents that may have influenced the results. The test report
39、 shall include all the information necessary for the complete identification of the sample. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 blank Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:11 GMT+00:00 2006, Uncontrolled
40、Copy, (c) BSI BS 684-2.44:1984 BSI 10-1999 Publications referred to See national foreword. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.44: 1984 ISO 6464:1983 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institu
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