Adsorptive stripping voltammetric behavior of nortriptyline hydrochloride and its determination in surfactant media

The effect of adding surface active agents to electrolytes containing nortriptyline hydrochloride on the voltammetric response of a hanging mercury drop electrode (HMDE) was studied. The current signal due to the reduction process was a function of the amount of nortriptyline hydrochloride, pH of the medium, type of the surfactant, and accumulation time at the electrode surface. Addition of Tween-20 to the nortriptyline hydrochloride containing electrolyte enhances the reduction current signal. Voltammograms of the drug with Tween-20 in Britton Robinson buffers of pH 2-11 exhibit a single well-defined reduction peak, which may be due to the reduction of -C horizontal lineC group. The reduction process was irreversible over the entire pH range, and the mechanism of reduction was postulated on the basis of controlled potential electrolysis and coulometry. Application of Tween-20 in the electrochemical determination of nortriptyline hydrochloride using square-wave voltammetry at the HMDE enhanced the detection limit of the analyte concentration from 8.24 ng/mL in the absence of surfactant to 0.92 ng/mL when present.