Utilization of fat retainers in supercritical fluid extraction for the selective extraction of polychlorinated biphenyls from a model fat sample

Two common fat retainers used in supercritical fluid extraction - basic alumina and the silica based adsorbent Florisil - were investigated using lard fat as model material. With a fat retainer in the extraction cell it was possible to obtain fat-free time windows. Activation by heating did not influence the length of the time windows, while deactivation of the retainers with 10% water (w/w) drastically decreased the fat retaining capabilities. The influence of modifier addition was also investigated. Finally, a method was developed, where basic alumina was utilized to selectively extract polychlorinated biphenyls (PCBs) from a model fat sample, containing PCBs, triglycerides and phospholipids. The PCBs could be quantitatively extracted in a totally fat-free time window. (C) 2000 Elsevier Science B.V. All rights reserved.