Extractive spectrophotometric determination of organophosphorus pesticides with molybdate and ethylene blue by flotation-dissolution method

A sensitive spectrophotometric method based on flotation dissolution method is described for the determination of trace levels of the organophosphorus pesticides such as dimethoate, quinolphos and parathion. Organophosphorus pesticides are converted into molybdophosphate in sulphuric acid medium and the complex floating on the surface of aqueous and organic layers along with Ethylene Blue as an ion associate is separated and disserved in acetone. Beer's law is obeyed in the concentration range of 0.005-0.04 ppm, 0.005-0.03 ppm, 0.005-0.04 ppm of dimethoate, quinolphos and parathion respectively. The method has been successfully applied for the determination of organophosphorus pesticides in water, soil, fruits and foliage samples respectively.