Determination of pesticides in high-water-content samples by off-line supercritical fluid extraction gas chromatography electron-capture detection

The optimization of supercritical fluid extraction of several organochlorine and organophosphorus pesticides is presented. The optimized method is compared with the classical sonication coupled to gel permeation chromatography as a clean-up method. The SFE method has been tested for 11 pesticides in spiked strawberries. At a spiking level of 100 ng/g, the pesticide recoveries were higher than 80%. The influence of the water content present in the sample is discussed. Two different approaches to solve this problem, which involve the use of anhydrous sodium sulfate mixed with the sample and alternatively the lyophilization, are presented too. (C) 1998 Elsevier Science B.V.