BS EN ISO 4048:2018 pdf free

BS EN ISO 4048:2018 pdf free.Leather-Chemical tests-Determination of matter soluble in dichloromethane and free fatty acid ontent
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.
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.
一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.
一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.
一If the sulfur should precipitate again, repeat the procedure.
一After the diethyl ether has been distilled off, dry the flask and residue and weigh.
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].
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.