BS EN ISO 4048 pdf free download

BS EN ISO 4048 pdf free download. Leather – Chemical tests – Determination of matter soluble in dichloromethane and free fatty acid content.
7 Sampling and preparation of the samples Sample in accordance with ISO 2418. If sampling in accordance to ISO 2418 is not possible, then details about sampling shall be given in the test report. Grind the leather in accordance with ISO 4044. Samples should be analysed in duplicate, if it is possible. 8 Procedure 8.1 General Weigh accurately using the analytical balance (6.4) (10 ± 0,1) g or (5 ± 0,1) g (if only soluble matter is determined) of the prepared leather sample and press evenly into the filter paper thimble or glass bell (6.2). Cover the leather with a thin layer of glass wool or cotton wad, or equivalent (6.6). Dry the extraction flask (see 6.1) with four glass beads in it by heating for 30 min at (102 ± 2) °C. Weigh after cooling in a desiccator (6.5). If determination of free fatty acids is not being carried out, boiling chips may be used as an alternative to glass beads. Two techniques for extraction of the fatty substances are described: 1) extraction using the Soxhlet apparatus (see 8.2); and 2) extraction using a pressurized extraction system (see 8.3). In cases of dispute, the Soxhlet extraction shall be used. A comparison of results obtained using both techniques is shown in Annex A and Annex B. 8.2 Extraction using the Soxhlet apparatus 8.2.1 Place the sample prepared in 8.1 into the extraction apparatus and begin continuous extraction with the dichloromethane (see 8.2.2). After at least 30 changes of solvent, distil the dichloromethane from the flask containing the extract (see 8.2.3). Dry the extract for at least 6 h in the oven (6.3), maintained at (102 ± 2) °C (if drops of water are visible before drying, add 1 ml to 2 ml of ethanol). Weigh after cooling for 30 min in a desiccator. 8.2.2 Dichloromethane (5.1.1) can also dissolve non-fatty materials from the leather, for example sulfur. (The presence of sulfur is recognizable by a yellow precipitate in the flask.) As sulfur causes difficulty, it can be removed in the following way. — Dissolve the extract in the smallest possible quantity of diethyl ether and filter through a little cotton wad (6.6) into a previously weighed flask. — After thoroughly washing out the cotton wad filter with ether, remove the ether from the extract in the flask by distillation over a hot water bath from which any flame has previously been removed. — If the sulfur should precipitate again, repeat the procedure. — After the diethyl ether has been distilled off, dry the flask and residue and weigh. 8.2.3 The extract may be used for analysis, for example to determine acid and saponification values of the fats, or to determine the free fatty acid content of the leather. After removal of the solvent, the extracted leather can be used for determination of water soluble substances in accordance with ISO 4098 [1]. 8.3 Extraction using a pressurized extraction system Place the sample prepared in 8.1 in the extraction apparatus and fill with dichloromethane as appropriate. The sample should be boiled at 180 °C for 40 min. Following this, sufficient dichloromethane should be distilled from the flask containing the extract to ensure that the extraction thimble is clear of the solvent. Extraction should then continue for a further 40 min, with the distilled dichloromethane percolating through the leather sample and collecting in the extraction vessel below. Finally, the remainder of the dichloromethane should be distilled from the flask containing the extract (see 8.2.2 and 8.2.3). Dry the extract for at least 6 h in the oven (6.3), maintained at (102 ± 2) °C (if drops of water are visible before drying, add 1 ml to 2 ml of ethanol). Weigh after cooling for 30 min in a desiccator.BS EN ISO 4048 pdf download.