Abstract
A nanocomposite miniaturized electrode modified with cobalt ferrite nanoparticles (CoFe2O4 NPs) was used for determination of donepezil (DON) in presence of memantine HCl. The voltammetric results indicate that CoFe2O4 NPs can remarkably enhance electrocatalytic activity toward the oxidation of donepezil in buffer solution. Scanning electrochemical microscopy (SEM) and transmission electron microscopy (TEM) were used for characterization of CoFe2O4 NPs and the modified electrode surface. Characteristics of the electrochemical responses of the modified electrode toward donopezil were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Experimental parameters including preconcentration time, scan rate and pulse height were optimized for high sensitivity. An In-situe electrochemical cleaning step was proposed for regeneration of the initial surface conditions of the electrode between measurements. The electrocatalytic oxidation current of donepezil was found to have a linear relation to concentration over the range from 5 to <= 20 mu M by the DPV method. The average recovery of DON in Aricept tablet was 97.49 with a %RSD <0.5%. The modified electrode can be applied to the determination of DON in tablets and urine samples with satisfactory results.