Analysing organophosphorus pesticides in wines using graphitized carbon black extraction cartridges

Abstract

A quick and simple method was developed to determine the residues of 15 organophosphorus pesticides of different polarity in grape wine, based on liquid-solid extraction with graphitized carbon black cartridges and capillary gas chromatography. Aliquots of diluted wine (10ml wine + 40ml deionized water) and 250mg graphitized carbon black cartridges were used to extract the analytes. The pesticides were eluted with 2 x 0. 5ml acetone and 3 x 2. 5ml ethyl acetate/acetone (80 : 20). The eluates were then dried with anhydrous sodium sulphate and concentrated to 1ml under a nitrogen current. After adding triphenylphosphate internal standard (i.s.), this extract was analysed by capillary gas chromatography using a nitrogen-phosphorus detector (GC-NPD). Pesticide recovery percentages at levels of 0.01 and 0.02 mug/ml were between 74% and 111%, with a 2–13% relative standard deviation interval. The chromatograms of extracts had few co-extracted species peaks, with no analytical interference. Dilution of the grape wine samples removed most of the pigments, thus producing clear extracts. The results indicate that liquid-solid extraction from wine samples using graphitized carbon is fast (25min per sample), efficient and reproducible for analysing organophosphorus pesticides of different polarity.