Decontamination of residues of three insecticides on Okra

Calcium hydroxide based alkali, synthetic cationic, anionic and non-ionic surfactants and a natural surfactant (a triterpenic saponin isolated from soapnut) were evauated for removal of residues of chlorpyrifos and etofenprox (both contact insecticides), and imidacloprid (a systemic insecticide). The saponin proved superior to the rest of the treatments for decontamination of chlorpyrifos, and the non-ionic surfactant for etofenprox. Different types of pesticides, depending on their solubility and lipophilicity, require specific reagents for their decontamination, but combination of non-edible alkali, the non-ionic surfactant Tween 80 and the saponin in the ratio of 1:1:1 removed substantially all the three test insecticides.