Abstract
The electrochemical oxidation of labetalol was investigated by cyclic, linear sweep and differential pulse voltammetry at carbon paste electrode in Britton-Robinson buffers over the pH range 2.0-10.0. For analytical purposes, a well-defined adsorption-controlled anodic peak was obtained in Britton-Robinson buffer at pH 2.0. By anodic adsorptive linear sweep and differential pulse voltammetry, linear calibration plots were obtained in the ranges of 2.5 x 10(-6)-1.0 x 10(-5) mol dm(-3) and 2.5 x 10(-8)-1.0 x 10(-5) mol dm(-3) for both techniques, respectively. Detection limits were found 1.0 x 10(-6) mol dm(-3) for LSV and 1.0 x 10(-8) mol dm(-3) for DPV. Based on this study, two simple, rapid, selective, and sensitive voltammetric methods were developed for the determination of labetalol in tablet dosage form. The preconcentration/medium exchange/voltammetry approach was applied for the drug determination in spiked human urine.