Abstract
An electrochemical sensor was designed and fabricated for electrocatalytic oxidation and determination of famotidine in pharmaceutical forms. The electrochemical oxidation process and its kinetics were investigated using cyclic voltammetry, steady-state polarization measurements, and chronoamperometry techniques, and also the analytical measurements were performed by amperometry. Upon addition of the drug into the solution, cyclic voltammograms of the fabricated sensor exhibited an increased anodic peak current associated with a decrease in the corresponding cathodic current. These results suggested an electrocatalytic EC' oxidation mechanism for famotidine on the oxyhydroxide species immobilized on the electrode surface. Accordingly, a mechanism involving generation of Ni(3+) active sites and their subsequent consumption by the drug was proposed. Moreover, the corresponding rate law under the control of charge transfer was developed and kinetic parameters were derived. A sensitive and time-saving amperometric procedure was also developed for the analysis of famotidine with a detection limit of 5.91 mmol L(-1). Using the developed amperometric procedure, famotidine was successfully analyzed in the presence of ibuprofen. The developed sensor in this study displayed enhanced sensitivity and selectivity, compared to some other reported methods.