Madhurima Gupta

Defatting leathers can be done by extraction with volatile hydrocarbon solvents, hexane or petroleum ether in a Soxhlet apparatus. Before determination, the skin sample must be washed with water from surfactants and dried.

To be precise one would have to assume that defatting is never 'complete', but achieved to a certain degree. Necessary should be defined by requirements of the successive step (deprotonation). Would assume that a good wetting of extraction liquid is necessary. In this case one could take this as critical parameter

Titus Sobisch can you please elaborate on what is meant by wetting of extraction liquid

Extraction liquid needs good contact with surface. E.g., water shows poor contact on fatty surface.