Electrooxidation and Low-tech Determination of Pantoprazole on a Disposable Pencil Graphite Electrode by the Use of Cationic Surfactant

The electrochemical oxidation of pantoprazole, a selective proton pump inhibitor, was studied in aqueous as well as aqueous/surfactant media at a disposable pencil graphite electrode using cyclic and adsorptive stripping voltammetric techniques. The sensitivity of the stripping voltammetric measurements was significantly improved when the cationic surfactant, cetyltrimethylammonium bromide (CTAB) was present in the neutral electrolyte solution. For analytical purposes, well resolved voltammetric peaks at +1.05 V (versus Ag/AgCl) were obtained in Britton-Robinson buffer at pH 7.0 containing 3×10-4 M CTAB using square-wave stripping mode (after 30 s accumulation at open-circuit condition). The process could be used to determine pantoprazole concentrations in the range of 2.4×10-8 - 7.1×10-7 M (9.2 - 272 µg L-1) with a detection limit of 7.0×10-9 M (2.7 µg L-1). The proposed method was applied to the determination of pantoprazole in pharmaceutical formulation and in the spiked human urine samples with acceptable recoveries.