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1、International Standard 6884 INTERNATIONAL ORGANIZATION FOR STANOARDlZATIONMEYHAPOAHAR OPrAHH3AUHfl no CTAH/lAPTH3Ai.lHHWRGANISATION INTERNATIONALE OE NORMALISATION Animal and vegetable fats and oils - Determination of ash Corps gras dorigines animale et vgtale - Dtermination des cendres First editio
2、n - 1985-12-15 UDC 665.2/.3:543.822 Ref. No. IS0 6884-1985 (E) Descriptors : agricultural products, animal fats. vegetable fats, animal oils, vegetable oils, chemical analysis, determination of content, ashes. - Price based on 2 pages 7 _ _ _ Foreword IS0 (the International Organization for Standard
3、ization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to
4、be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as Internati
5、onal Standards by the IS0 Council. They are approved in accordance with IS0 procedures requiring at least 75 % approval by the member bodies voting. International Standard IS0 6884 was prepared by Technical Committee ISO/TC 3 4 , Agricultural food products. Users should note that all International S
6、tandards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. O International Organization for Standardizetion, 19% 0 Printed in Switzerland INTERN AT1 ON AL STAN DARD ISO 6884-1985 (E) Animal a
7、nd vegetable fats and oils - Determination of ash 1 Scope and field of application This International Standard specifies a method for the deter- mination of ash, applicable to all animal and vegetable fats and oils, including acid oils. 2 References IS0 661, Animal and vegetable fats and oils - Prep
8、aration of test sample. IS0 5555, Animal and vegetable fats and oils - Sampling. 3 Definition For the purpose of this International Standard, the following definition applies. ash : The inorganic residue left after incineration under the con- ditions specified, and expressed as a percentage by mass.
9、 4 Principle Incineration of a test portion at a specified temperature and weighing the residue obtained. 5 Reagents All the reagents shall be of recognized analytical quality and the water used shall be distilled water or water of at least equivalent purity. 6 Apparatus Usual laboratory equipment,
10、and in particular 6.1 or platinum. Crucible (low form) of 50 rnl capacity, preferably of silica 6.2 Hotplate or flame burner. 6.3 600 OC. Furnace, capable of being operated between 500 and 6.4 Filter-paper, ashless. 6.5 Water-bath, boiling. 6.6 Desiccator. 7 Sampling See IS0 5555. 8 Procedure 8.1 Pr
11、epare the test sample from the laboratory sample in accord- ance with IS0 661. Preparation of the test sample 8.2 Crude and refined fats and oils 5.1 Hydrogen peroxide solution, 10 % (V/V). 5.2 Ammonium carbonate. 8.2.1 First heat the crucible (6.1) in the furnace (6.3) maintain- ed at 550-600 OC, t
12、hen cool in a desiccator (6.6) and weigh to 1 -,-,- IS0 6884-1985 (E) 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 the hotplate or over the flame burner (6.21 in a fume cupboard until the sample ignites. NOTES 1 For low ash c
13、ontents, a larger test portion may be taken by adding successive portions of 10 g after the initial ashing: for high ash con- tents, a smaller test portion may be used. With an increased quantity of oil, a wick of ashless filter-paper may be inserted and lit whilst heating the oii on a hotplate. 2 T
14、he 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) maintained at 550-600 OC. Maintain at this temperature for 4 h or for a shorter time if a carbon-free residue i
15、s 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 residue, 8.2.3 To assist removal of carbon if the residue is not carbon- free after 4 h, add a few drops of h
16、ydrogen peroxide 5*1), dry on a boiling water-bath (6.51 and reheat in the furnace (6.3) until carbon-free. NOTE - It may be necessary to repeat this treatment. 8.2.4 When the residue is carbon-free, allow to cool in a desiccator (6.6) and weigh to the nearest 1 mg. 8.3 Acid oils 8.3.1 the crucible
17、in the furnace maintained at 500-550 OC. Follow the procedure in 8.2.1, but in the first step heat 8,3,2 When the burning ceases, allow the crucible to cool and take up the residue in water. Filter through an ashless filter- paper (6.4) and retain the filtrate in a beaker. 2 8.3.3 Place the filter-p
18、aper with the residue in the crucible, then place the crucible in an oven at 103 f 2 O C until the paper has dried. Transfer the crucible to the hotplate or flame burner and heat carefully as described in 8.2.1 until burning ceases. Then heat in the furnace (6.3) at a temperature of 500-550 OC until
19、 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 filtrate retained in 8.3.2 quantitatively to the crucible (8.3.3). Evaporate to dryness on a boil
20、ing water- bath (6.5). Add 0,5 to 2 g of ammonium carbonate (5.2) in order to recar- bonate the ash, then heat the residue in the furnace (6.3) at a temperature of 500-550 OC. Allow the crucible to cool in a desiccator (6.6) and weigh to the nearest 1 mg. 9 Expression of results The ash content, exp
21、ressed as a percentage by mass, is given by the formula 100 ms - mi) mo where mo is the mass, in grams, of the test portion; ml is the mass, in grams, of the empty crucible: m2 is the mass, in grams, of the crucible and ash. 10 Test report The test report shall show the method used and the result ob
22、tained. 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 information necessary for the complete identification of the sample.