ISO 4048:2008 specifies a method for the determination of the substances in leather which are soluble in dichloromethane. This method is applicable to all types of leather
ISO 4048:2008 includes two techniques for extraction of the fatty substances: 1) extraction using the Soxhlet apparatus; and 2) extraction using a pressurized extraction system. As the extraction is frequently done in conjunction with determination of the free fatty acid content of the leather, a suitable procedure for determination of the free fatty acids extracted by this method is included.
The apparatus and technique described in this method are also suitable for the extraction of leather by solvents other than dichloromethane (although the temperature conditions may need to be varied for high pressure extraction).