This International Standard 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.
Not all fatty and similar substances can be extracted from leather with organic solvents; they may be in part
soluble and partly bound to the leather. On the other hand, the solvent can dissolve non-fatty substances, e.g.
sulfur and impregnants, both of which cause difficulty in the determination of the acid value and saponification
value of the fat.
This International Standard 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 by solvents other
than dichloromethane (although the temperature conditions may need to be varied for high pressure
extraction).