Abstract
Recovery of organophosphorus insecticides, quinalphos, chlorpyrifos and methidathion from soil were examined by extracting with carbon dioxide under supercritical state. Extraction conditions were designed at 100, 150, 200, 250 and 300 atm and under 40, 50 or 60°C. The better recovery was obtained by amending 2ml of methanol into soil sample before extraction. The best extraction condition was found to be at 300 atm and under 50°C, at 200 atm and under 60°C, and at 100 atm and under 60°C for quinalphos, chlorpyrifos and methidathion, respectively.
