Electroanalytical performance of boron doped diamond electrode for the determination of solifenacin

Abstract

The anticholinergic drug, solifenacin (SOL), is frequently used for the treatments in urological tract for urinary incontinence, and urinary frequency [1]. As an electroactive molecule, SOL can be an appropriate target analyte for voltammetric measurements. Boron doped diamond electrode (BDDE) was selected as a working electrode because of its unique electrochemical properties and emphasis on anodic measurements [2]. Prior to the voltammetric measurements of SOL, BDDE was electrochemically activated in the supporting electrolyte by anodic pretreatment (+2.0 V; 30 s) to achieve an oxygen terminated surface [3]. The voltammetric behavior of SOL was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in a model system. Based on the CV measurements it is proved that the certain electrooxidation process is diffusion controlled. Various experimental parameters were optimized including the pH of the aqueous Britton-Robinson (B-R) buffer as a supporting electrolyte (from pH 2.0 to 11.98) in the potential range from -0.3 V to 1.6 V vs saturated calomel electrode. Depending on the pH value of the B-R buffer one oxidation peak of SOL was obtained at maxima of peak potential around 1.1 V. The most intensive peak of the target analyte was at pH 11.0 which was chosen as an optimal pH value for further measurements. Based on the correlation of SOL peak intensity and different concentrations, the developed DPV method was characterized by a linear concentration range from 0.015 to 0.907 µg mL-1, coefficient correlation of 0.999, and relative standard deviation of 0.33%. Taking into account the sensitivity of the developed DPV method towards the electrochemical oxidation of SOL, a very low detection limit of 0.005 µg mL-1 in the model system is achieved. The BDDE showed adequate selectivity for SOL in the presence of investigated interferents. The obtained results indicate that BDDE with an optimized DPV method could be applied for the trace-level electroanalytical determination of SOL in real samples.