Sensitive Determination of Propoxur by Spectrophotometry Using 3-Aminopyridine

Abstract

A simple spectrophotometric method for the determination of propoxur, a widely used insecticide, in various environmental samples and pesticide formulations is described. The method is based on the coupling of the hydrolysis product of propoxur with diazotized 3-aminopyridine in an alkaline medium, to form an azo-dye which has a maximum absorbance at 463 nm. Beer’s law is obeyed over the concentration range of 0.05 to 1.2 µg ml^-1 of propoxur. The molar absorptivity and Sandell’s sensitivity are found to be 3.10 × 10⁴ l mol^-1 cm^-1 and 0.007 µg cm^-2, respectively. The important analytical parameters and optimum reaction conditions were evaluated. The method is free from the interference of other commonly used pesticides and inorganic metal ions.