SUPERCRITICAL-FLUID EXTRACTION OF ORGANOPHOSPHORUS PESTICIDES FROM ORANGE SAMPLES - EFFECT OF SOLID ADDITIVES ON RECOVERY

A method based on extraction with supercritical carbon dioxide has bee n developed for the analysis of pesticides in fruit. The method was te sted on ten organophosphorus pesticides and dicloran in orange samples . Various solid additives including anhydrous sodium sulfate, Extrelut and diatomaceous earth were examined as extraction enhancers. Also te sted were magnesium silicate as interference adsorbent, to increase se lectivity, and sodium carbonate as alkaline salt, to prevent acidifica tion of the sample by CO2. The recoveries obtained by SFE (92-104 %; m ean relative standard deviation 10 %) were higher than those of conven tional methods. The polar pesticide methamidophos, however, was not re covered.