Development of a novel supercritical fluid extraction procedure for lanolin extraction from raw wool Original Research Article

A procedure based on supercritical fluid extraction (SFE) has been developed for the determination of lanolin present on raw wool fibres. Residual lanolin remaining in the fibres following a SFE was determined according to a standard method (Soxhlet with dichloromethane) for all the SFE conditions evaluated. Selected extraction variables affecting the SFE were optimised in two steps. In the first step, the type of modifier was evaluated keeping constant the remaining variables (pressure, temperature, percentage of modifier) and in the second step, pressure, temperature and modifier volume were optimised by using the experimental design approach. Carbon dioxide-acetone at high-solubility conditions (i.e. low temperature, high pressure and 20% acetone in CO2) provided comparable results to Soxhlet extraction with dichloromethane (91 ± 2%, n = 5). However, extraction time was reduced to 2 h 30 min, chlorinated solvent usage is avoided, and the accuracy of the determination is improved because lanolin Soxhlet coextractants (mineral salts, proteins, etc.) are not extracted in SFE.