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1、BRITISH STANDARD CONFIRMED NOVEMBER 1992 BS 684-2.2: 1986 ISO 6884:1985 Methods of analysis of Fats and fatty oils Part 2: Other methods Section 2.2 Determination of ash ISO title: Animal and vegetable fats and oils Determination of ash IMPORTANT NOTE. It is essential that BS 684-0, which is publish
2、ed separately, be read in conjunction with this Section. UDC 665.1.014:543.822 Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.2:1986 This British Standard, having been prepared under the direction of the Food and Agriculture Standa
3、rds Committee, was published under the authority of the Board of BSI and comes into effect on 28 November 1986 BSI 12-1999 First published October 1976 First revision November 1986 The following BSI references relate to the work on this standard: Committee reference FAC/18 Draft for comment 84/54242
4、DC ISBN 0 580 15379 7 National foreword This revision of Section 2.2 of BS 684, which has been prepared under the direction of the Food and Agriculture Standards Committee, supersedes BS 684-2.2:1976, which is withdrawn. It differs from BS 684-2.2:1976 in that the temperature of ignition is 550 C to
5、 600 C and not 600 C, the crucible may be of platinum (as well as silica) but not porcelain and a procedure for acid oils is included. This Section is identical with ISO 6884:1985 “Animal and vegetable fats and oils Determination of ash” published by the International Organization for Standardizatio
6、n (ISO) and in the preparation of which the UK played a full part. 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 used in
7、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. In British Standards it is current practice to use the symbol “mL” for millilitre rat
8、her than “ml”. Wherever the words “International Standard” appear, referring to this standard, 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 applicatio
9、n. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) an
10、d may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Cross-references International StandardCorresponding British Standard ISO 661:1980BS 684 Methods of analysis of fats and fatty oils Part 0:1982 General introduction (Appendix B Identical)
11、 ISO 5555:1983BS 627:1982 Methods for sampling animal and vegetable fat and oils (Technically equivalent) Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.2:1986 BSI 1
12、2-1999i Contents Page National forewordInside front cover 1Scope and field of application1 2References1 3Definition1 4Principle1 5Reagents1 6Apparatus1 7Sampling1 8Procedure1 9Expression of results2 10Test report2 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na,
13、Wed Dec 06 13:26:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.2:1986 BSI 12-19991 1 Scope and field of application This International Standard specifies a method for the dete
14、rmination of ash, applicable to all animal and vegetable fats and oils, including acid oils. 2 References ISO 661, Animal and vegetable fats and oils Preparation of test sample. ISO 5555, Animal and vegetable fats and oils Sampling. 3 Definition For the purpose of this International Standard, the fo
15、llowing definition applies. ash the inorganic residue left after incineration under the conditions specified, and expressed as a percentage by mass 4 Principle Incineration of a test portion at a specified temperature and weighing the residue obtained. 5 Reagents All the reagents shall be of recogni
16、zed analytical quality and the water used shall be distilled water or water of at least equivalent purity. 5.1 Hydrogen peroxide solution, 10 % (V/V). 5.2 Ammonium carbonate 6 Apparatus Usual laboratory equipment, and in particular 6.1 Crucible (low form) of 50 ml capacity, preferably of silica or p
17、latinum. 6.2 Hotplate or flame burner. 6.3 Furnace, capable of being operated between 500 and 600 C. 6.4 Filter-paper, ashless. 6.5 Water-bath, boiling. 6.6 Desiccator 7 Sampling See ISO 5555. 8 Procedure 8.1 Preparation of the test sample Prepare the test sample from the laboratory sample in accord
18、ance with ISO 661. 8.2 Crude and refined fats and oils 8.2.1 First heat the crucible (6.1) in the furnace (6.3) maintained at 550600 C, then cool in a desiccator (6.6) and weigh to the nearest 1 mg. Weigh, to the nearest 10 mg, about 10 g of the test sample (8.1) into the crucible. Heat carefully on
19、 the hotplate or over the flame burner (6.2) in a fume cupboard until the sample ignites. NOTE 1For low ash contents, a larger test portion may be taken by adding successive portions of 10 g after the initial ashing; for high ash contents, a smaller test portion may be used. With an increased quanti
20、ty of oil, a wick of ashless filter-paper may be inserted and lit whilst heating the oil on a hotplate. NOTE 2The initial heating may be carried out in the mouth of the furnace, if the furnace is installed in a fume cupboard. 8.2.2 When the burning ceases, transfer the crucible to the furnace (6.3)
21、maintained at 550600 C. Maintain at this temperature for 4 h or for a shorter time if a carbon-free residue is obtained more rapidly. A carbon-free residue is shown by the appearance of the ash, which becomes red-brown (due to the presence of iron) or white, with no black particles remaining in the
22、residue. 8.2.3 To assist removal of carbon if the residue is not carbon-free after 4 h, add a few drops of hydrogen peroxide (5.1), dry on a boiling water-bath (6.5) and reheat in the furnace (6.3) until carbon-free. NOTEIt may be necessary to repeat this treatment. 8.2.4 When the residue is carbon-
23、free, allow to cool in a desiccator (6.6) and weigh to the nearest 1 mg. 8.3 Acid oils 8.3.1 Follow the procedure in 8.2.1, but in the first step heat the crucible in the furnace maintained at 500550 C. 8.3.2 When the burning ceases, allow the crucible to cool and take up the residue in water. Filte
24、r through an ashless filter-paper (6.4) and retain the filtrate in a beaker. 8.3.3 Place the filter-paper with the residue in the crucible, then place the crucible in an oven at 103 2 C until the paper has dried. Transfer the crucible to the hotplate or flame burner and heat carefully as described i
25、n 8.2.1 until burning ceases. Then heat in the furnace (6.3) at a temperature of 500550 C until the carbon particles disappear or until there is no change in appearance of the residue. If the residue is not carbon-free, proceed as described in 8.2.3. Allow the crucible to cool. 8.3.4 Transfer the fi
26、ltrate retained in 8.3.2 quantitatively to the crucible (8.3.3). Evaporate to dryness on a boiling water-bath (6.5). Add 0,5 to 2 g of ammonium carbonate (5.2) in order to recarbonate the ash, then heat the residue in the furnace (6.3) at a temperature of 500550 C. Allow the crucible to cool in a de
27、siccator (6.6) and weigh to the nearest 1 mg. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.2:1986 2 BSI 12-1999 9 Expression of results The ash content, expressed as a percentage by mass, is given by the formula 10 Test report Th
28、e test report shall show the method used and the result obtained. It shall also mention any operating conditions not specified in this International Standard, or regarded as optional, together with details of any incidents likely to have influenced the result. The test report shall include all the i
29、nformation necessary for the complete identification of the sample. where m0is the mass, in grams, of the test portion; m1is the mass, in grams, of the empty crucible; m2is the mass, in grams, of the crucible and ash. 100 m2m1() m0 - - Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:50
30、GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.2:1986 BSI 12-1999 Publications referred to See national foreword. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 13:26:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 684-2.2: 1986 ISO 6884:1985 BSI 389 Chiswick High Road London W4 4AL BS
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