A simple colorimetric method for the determination of carbofuran and its application in environmental and biological samples

Abstract

A simple spectrophotometric method based on the coupling of a carbamate pesticide, carbofuran (2, 3-dihydro, 2, 2-dimethyl-7-benzofuranyl methyl carbamate) with diazotized p-aminoacetophenone (DPAAP) under alkaline condition is described. The orange dye formed by coupling of the pesticide with DPAAP was measured at 460 nm. Beer's law is obeyed over the concentration range of 0.1 to 1.2 μg mL-1 of carbofuran in a final solution of 25 mL. Molar absorptivity and Sandell's sensitivity were found to be 1.2×105 L mol-1 cm-1 and 0.0014 μg cm-2 respectively. The optimum reaction condition and other analytical conditions were evaluated. The effect of interfering ions on the determination of carbofuran is described. The method has been successfully applied to the determination of carbofuran in rice, wheat and various environmental and biological samples. The results obtained were compared with other spectrophotometric and chromatographic methods reported for carbofuran. ©2007 Sociedade Brasileira de Química.