BS EN ISO 663:2001 pdf – Animal and vegetable fats and oils — Determination of insoluble impurities content.
1 Scope This International Standard specifies a method for the determination of the insoluble impurities content of animal and vegetable fats and oils. If it is not desired to include soaps (particularly calcium soaps) or oxidized fatty acids in the insoluble impurities content, it is necessary to use a different solvent and procedure. In this case the method should be the subject of agreement between the parties concerned. 2 Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 661 :1 989, Animalandvegetable fats andoils — Preparation oftestsample. 3 Term and definition For the purposes of this International Standard, the following term and definition applies. 3.1 insoluble impurities content quantity of dirt and other foreign matter insoluble in n-hexane or light petroleum under the conditions specified in this International Standard NOTE 1 The content is expressed as a percentage by mass. NOTE 2 These impurities include mechanical impurities, mineral substances, carbohydrates, nitrogenous substances, various resins, calcium soaps, oxidized fatty acids, fatty acid lactones, and (in part) alkali soaps, hydroxy-fatty acids and their glycerides. 4 Principle A test portion is treated with an excess of n-hexane or light petroleum, then the solution obtained is filtered. The filter and residue are washed with the same solvent, then dried at 1 03 °C, and weighed.
9 Procedure 9.1 Test portion Weigh, to the nearest 0,01 g, approximately 20 g of the test sample (clause 8) into a conical flask (6.3). 9.2 Determination 9.2.1 Dry the filter paper and the vessel (6.5) with its lid, or the filter crucible (6.6), in the oven (6.2) set at 1 03 °C. Allow to cool in the desiccator (6.4) and weigh to the nearest 0,001 g. 9.2.2 Add 200 ml of n-hexane or light petroleum (5.1 ) to the flask containing the test portion (9.1 ). Stopper the flask and shake. For castor oil, the quantity of solvent may be increased to facilitate the operation, and this may necessitate the use of a larger flask. Leave to stand at about 20 °C for about 30 min. 9.2.3 Filter through the filter paper in a suitable funnel, or through the filter crucible, using suction if necessary. Wash the filter paper or filter crucible by pouring through it small amounts of the same solvent as used in 9.2.2, but no more than is necessary for the final filtrate to be free from fat or oil. Warm the solvent, if necessary, to a maximum temperature of 60 °C, in order to dissolve any solidified fats retained on the filter.5 Reagent Use only reagents of recognized analytical grade. 5.1 n-Hexane, or in the absence of this, light petroleum, having a distillation range between 30 °C and 60 °C and having a bromine value less than 1 . For either solvent, the residue on complete evaporation shall not exceed 0,002 g per 1 00 ml. 5.2 Kieselguhr, purified, calcinated, loss in mass at 900 °C (red heat) of 0,2 % by mass. 6 Apparatus Usual laboratory apparatus and, in particular, the following. 6.1 Analytical balance with an accuracy of ? 0,001 g. 6.2 Electric drying oven, capable of operating at 1 03 °C ? 2 °C. 6.3 Conical flask, of 250 ml capacity, with ground glass stopper. 6.4 Desiccateur, containing an efficient desiccant. 6.5 Ashless filter paper (maximum ash content 0,01 %, by mass); retention value of 98 %, by mass, for particles of size greater than 2,5 ?m 1 ) , or an equivalent glass-fibre filter, of diameter 1 20 mm, together with a metal (preferably aluminium) or glass vessel with a well-fitting lid. (Alternative to 6.6 for all products except acid oils.) 6.6 Filter crucible, glass, of grade P1 6 (pore size 1 0 ?m to 1 6 ?m), diameter 40 mm, of capacity 50 ml, together with a suction bottle. (Alternative to 6.5 for all products including acid oils.) 7 Sampling It is important that the laboratory receive a sample which is truly representative and has not been damaged or changed during transport and storage. Sampling is not part of the method specified in this International Standard. A recommended sampling method is given in ISO 5555. 8 Preparation of test sample Prepare the test sample in accordance with ISO 661 .