APPLICATION OF SUPERCRITICAL-FLUID EXTRACTION FOR ANALYSIS OF ORGANOPHOSPHATES IN CEREALS

Application of supercritical fluid extraction (SFE) utilizing pure car bon dioxide for selective isolation of organophosphates from contamina ted cereals has been tested. At the beginning of the experiments the e xtractability of added standards from an empty extraction vessel (thim ble) and from various materials such as filter paper, sand, Celite and anhydrous sodium sulfate was tested to estimate the behavior of organ ophosphates. Further method development was carried out using a spiked sample of flour, which was analyzed within the proficiency testing fo r organophosphorus pesticides analysis (round 7) organized by Food Ana lysis Performance Assessment Scheme (FAPAS, MAFF-UK). Comparison of th e SFE method with a classical method currently employed for sample pre paration (i.e. extraction with acetone/methanol mixture followed by ge l permeation chromatographic clean up) showed advantages of the SFE te chnique such as simplification of the sample preparation step and ther eby significant speeding up of the determination of organophosphates i n cereals.