SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF FENOXAPROP-P-ETHYL HERBICIDE IN WHEAT AND BARLEY GRAINS USING CHARGE TRANSFER COMPLEX

A simple and sensitive spectrophotometric method was developed for determination of fenoxaprop-p-ethyl herbicide in food samples. The method is based on acid hydrolysis of fenoxaprop-p-ethyl it gives the product 6- chloro-2, 3- dihydrobenzoxazol-2-one (CDHB) and ethyl 2-(4-hydroxyphenoxy) propionate (EHPP).The 6-chloro- 2,3- dihydrobenzoxazol-2-one (CDHB) was reacted with Fe (II) to form yellow color complex. Its λ_max was found to be 430nm. The influences of various experimental parameters on the absorbance of the charge transfer complex of fenoxaprop-p-ethyl with Fe (II) are studied. The absorbance of complex was measured at 430 nm. The charge transfer complex of herbicide with Fe (II) shows molar absortivity 4.2x10^4 L. mol^-1. cm^-1. Analytical parameters were optimized and successfully applied to the determination of fenoxaprop-p-ethyl in various samples. The method shows a linear range from 2-24 μg mL^-1. The percent recovery for determination of fenoxaprop-p-ethyl in commercial formulations was found to be 84 ± 0.067 –98 ± 0.060 %. The limit of detection and quantification was found to be 0.20 μg mL^-1 and 0.67μg mL^-1 respectively.