AUTOMATED-ANALYSIS OF ORGANOPHOSPHORUS PE STICIDE-RESIDUES IN FOODS USING SUPERCRITICAL-FLUID EXTRACTION

Organophosphorus pesticide residues in foods were extracted by means o f supercritical fluid extraction (SFE). The extracted pesticides were determined consecutively by GC-FPD detection under the control oi a co mputer. Samples were mixed with two kinds of drying agents, diatomaceo us earth or a super-absorbent polymer, before extraction to remove wat er. Thirty-three out of 35 pesticides tested were extracted with good recovery and determined with high precision, though acephate and metha midophos were hardly recovered when diatomaceous earth was used and po orly recovered with the super-absorbent polymer. Most interfering subs tances, such as fats and green food colors, were not extracted during the proposed extraction process. These results suggest that extraction by SFE coupled with selective detection is suitable for the analysis of pesticide residues in foods.