Sweep Co-Distillation Cleanup of Fortified Edible Oils for Determination of Organophosphate and Chlorinated Hydrocarbon Pesticides

Abstract

Abstract The technique of sweep co-distillation developed for organophosphate pesticides in fruits and vegetables was expanded for application to organophosphate and chlorinated hydrocarbon pesticides in edible oils. A modified longer and wider Storherr tube and heating assembly was used in this work and 3 mm diameter glass beads replaced the glass wool packing used in crop work. The work on oils was performed at 248 ± 3°C with a nitrogen flow of 600 ml/min and injection of a sweeping solvent every 3 minutes for 30 minutes. Phosphate pesticides were analyzed by GLC with a potassium thermionic detector and chlorinated pesticides were determined by ECGLC, after a micro Florisil column was used to eliminate extraneous peaks. Recoveries of ten phosphate pesticides from nine edible oils ranged from 74 to 100% at fortification levels of 0.04 to 6.25 ppm; average recoveries for the individual pesticides were 90—99%. Average recoveries for the chlorinated pesticides ranged from a low of 75% for Tedion to a high of 98% for endrin and dieldrin. Sensitivity of 0.01 is readily obtainable for compounds such as parathion and heptachlor cpoxide. The sweep co-distillation method is suitable for the rapid determination of the 14 chlorinated and 10 organophosphate pesticides tested in edible oils