Spectrophotometric Determination of Residual Amount of Propoxur in Fruit and Vegetable

In an ammoniacal solution, azo dye was formed between phenate (produced by hydrolysis of propoxur in an alkaline medium) and diazo compound (produced by diazotization between sulfanilic acid and nitrite), with its absorption max. at the wavelength of 427 nm. Based on these facts, a spectrophotometric method for determination of propoxur in fruit and vegetable was proposed. Linear relationship between the values of absorbance and mass concentration of propoxur was obtained in the range of 0.17-2.04 mg·L-1, with detection limit (3s/k) of 0.03 mg·L-1. The present method was used in the analysis of samples of fruit and vegetable, giving values of RSD′s (n=5) in the range of 0.3%-0.7%. Test for recovery was performed by standard addition method, result of average recovery obtained was 96%.