Simple spectrophotometric screening method for the detection of organophosphate pesticides on plant material

Abstract

A simple, rapid and sensitive method has been developed for the determination of organophosphorus pesticides such as anthio, perfekthion and monocrotophos on the surface of plants. The method is based on the formation of molybdophosphoric acid in acidic solution followed by its reduction with the reducing agent malonyl dihydrazide to give a blue molybdenum complex which is extracted into butanol. The dye shows an absorption maximum at 780 nm. The molar absorptivity and Sandell's sensitivity are 3.55 ± 0.05 × 10⁴ dm³ mol^–1 cm^–1 and 0.007 µg, respectively. The proposed method is free from interferences from Mo, Cu and Ni ions.