A spectrophotometric method for the determination of fenvalerate and cypermethrin in presence of each other

A simple spectrophotometric method has been proposed for the determination of widely used pyrethroid pesticides, cypermethrin and fenvalerate. The method is based on the hydrolysis of these pesticides, upon which they release cyanide. The cyanide is reacted with bromine and pyridine to form glutaconic aldehyde, which is then coupled with sulphanilic acid to give an orange red dye in acidic medium having maximum absorbance at 480 nm. Beer’s law is obeyed in the ranges of 0.18–1.12 and 0.08–0.64 μg/mL for fenvalerate and cypermethrin, respectively. The proposed method is sensitive and found to be free from interferences of a large number of foreign species and other pesticides. The proposed method could be applied to the determination of fenvalerate and cypermethrin in their formulations and environmental samples.