Supercritical fluid extraction of organophosphate and carbamate insecticides in honeybees

Supercritical fluid extraction (SFE) was evaluated for the extraction of organophosphate and carbamate insecticides in honeybees. Extracts were analyzed by gas chromatography (GC) with nitrogen-phosphorus detection or flame-photometric detection with confirmation by GC with ion-trap mass spectrometry. Samples were mixed with diatomaceous earth and optimal extraction conditions were: (1) CO2 density of 0.7 g/mL, (2) 60 degrees C, (3) 2 min equilibration time, (4) 40 mt of CO2, and (5) 1.6 mL/min flow rate. Analytes were trapped on octadecyl silane (ODS) and eluted with acetonitrile. No further cleanup was necessary and chromatographic interferences in SFE extracts were comparable to those in solvent extracts that had undergone extensive cleanup procedures. Recoveries from honeybees fortified at 1 land 0.1 mu g/g were greater than 75% for all pesticides studied except omethoate. Samples containing residues were also extracted by SEE, and there was good quantitative agreement with results from analyses based on solvent extractions.