Supercritical fluid extraction of organochlorine pesticides in eggs

The efficacy of supercritical fluid extraction (SFE) for the recovery of 16 common organochlorine pesticides (OCPs) from liquid whole eggs was investigated by employing supercritical carbon dioxide (SC-CO2) without the use of a solvent modifier to minimize interfering coextractives. The OCPs tested included aldrin; alpha-, beta-, delta-, and gamma-BHCs; p,p'-DDD, -DDE, and -DDT; dieldrin; endosulfans I, II, and sulfate; endrin; endrin aldehyde; heptachlor; and heptachlor epoxide. The SFE conditions were as follows: 10000 psi (680 bar),40 degrees C, SC-CO2 now rate of 3.0 L/min with an extraction time of 40 min for a total of 120 L of CO2. The OCPs were trapped off-line in an SPE cartridge containing Florisil and then eluted by an acetone/hexane mixture and analyzed by gas chromatography-electron capture detection (GC-ECD). Recovery studies were carried out on homogenized eggs fortified at the 0.05, 0.10, and 0.20 ppm levels. At the lowest level, 0.05 ppm, recoveries ranged from 81.8 to 108.3%, with CVs <9.8%. All recoveries were significantly higher than those obtained by an AOAC/ FDA solvent extraction method. Eggs containing incurred endosulfan I were also effectively extracted by SFE. This study suggests that the application of SFE for the extraction of OCPs from eggs will. result in significant savings in analysis time and lower solvent use and disposal costs compared to conventional solvent extraction procedures.