Development and Validation of Spectrophotometric Method for Determination of Oxyfluorfen Herbicide Residues

Abstract

Simple spectrophotometricmethod has been developed and validated for the determination of oxyfluorfen herbicide residues. The proposed method is based on the formation of an orange charge- transfer complex between oxyfluorfen pesticideas electron donor and 1,2- naphthoquinone-4-sulphonate (NQS) as electron acceptor. In basic medium pH 13.0, an orange colored product exhibiting maximum absorption peak (λ max) at 460 nm. The variables that affected the reaction such as pH, concentration and volume of NQS reagent, amount of buffer solution and reaction time were carefully studied and optimized. Under the optimum conditions, Beer’s law is obeyed in the range 0.4-4.0 μg/ mL of oxyfluorfen. The linear regression equation of the calibration curve is A=0.0906+0.2579 c (μg/mL), with a linear regression correlation coefficient of 0.9993. The molar absorptivity was 1.33 × 105 l/mol cm. The limits of detection (LOD) limits of quantification (LOQ) were found to be 0.12 μg/ mL, 0.36 μg/mL, respectively. The recovery rate is in the range of 93.50-103.00% was obtained. The proposed method has been successfully applied to the determination of oxyflourfen pesticide residues in tomato, onion and water with good accuracy and precision.