In this work, the supercritical fractionation of fatty acid ethyl estersă derived from fish oil was carried out with carbon dioxide at 333 K andă 14.5 MPa. The feed mixture is very complex, with over 80 differentă compounds detected by GC. Among them, the EicosaPentaenoic Acid (EPA)ă and DodecaHexaenoic Acid (DHA) ethyl esters are of major industrială interest since the consumption of these omega-3 acids has been linked toă a reduced risk of cardiovascular diseases. The influence of the processă parameters on the separation efficiency is an important point for ană economic analysis of the overall purification process. First, theă partition of the feed mixture was determined for differentă solvent-to-feed ratios varying between 21.8 and 143; the extract yieldă (i.e. the mass fraction of feed recovered as extract) has beenă calculated for each condition. Then, a new simplified equilibrium-stageă model was developed and applied to the mixture. Supposing a constantă distribution ratio, this model is able to correlate the influence of theă solvent-to-feed ratio (through a calculated extract yield) on theă concentration of the major 24 compounds present either in the feed or ină the extract and raffinate, including components with low, medium andă high distribution ratios. (C) 2016 Elsevier B.V. All rights reserved.