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

A procedure based on supercritical fluid extraction (SFE) has been develope d for the determination of lanolin present on raw wool fibres, Residual lan olin remaining in the fibres following a SFE was determined according to a standard method (Soxhlet with dichloromethane) for all the SFE conditions e valuated. Selected extraction variables affecting the SFE were optimised in two steps. Ln the first step, the type of modifier was evaluated keeping c onstant the remaining variables (pressure, temperature. percentage of modif ier) and in the second step, pressure, temperature and modifier volume were optimised by using the experimental design approach. Carbon dioxide-aceton e at high-solubility conditions (i.e, low temperature, high pressure and 20 % acetone in CO2) provided comparable results to Soxhlet extraction with di chloromethane (91 +/- 2%, n = 5). However, extraction time was reduced to 2 h 30 min, chlorinated solvent usage is avoided, and the accuracy of the de termination is improved because lanolin Soxhlet coextractants (mineral salt s, proteins, etc.) are not extracted in SFE. (C) 1999 Elsevier Science B.V. All rights reserved.