| Abstract: | Photodegradation of the organophosphorous insecticide quinalphos (O, O-diethyl O-quinoxalin-2-yl phosphorothioate) has been studied. On exposure to natural sunlight, quinalphos was photodegraded with half-lives of 30 days in distilled water, 20–23 days in tap and rain water and ≤5 days in 2% aqueous acetone. Quinalphos underwent photoisomerisation, oxidation from P=S to the P=O group and de-esterification. Photoproducts were isolated and characterised by spectroscopic methods. When applied on soil thin-layer plates quinalphos was promptly dissipated with a half-life of ≤6 days. |
