TiO2 modified carbon paste sensor for voltammetric analysis and chemometric optimization approach of amlodipine in commercial formulation

A new square wave adsorptive stripping voltammetric (SWAdSV) approach using experimental design and optimization methodology was developed for the quantitative estimation of amlodipine (AMP) in pharmaceutical tablets. To this end, a new carbon paste electrode (CPE) system was fabricated using titanium dioxide (TiO2) nanoparticles to get very well-defined oxidation peak current of AMP under the optimized conditions. Optimal electrochemical conditions for three factor variables, the pH, the accumulation potential, and the accumulation time, were obtained by applying a 33 full factorial design and optimization technique to the oxidation of AMP on the TiO2 modified CPE (TiO2-CPE) system. The numerical values of the optimal voltammetric parameters consisting of the pH, accumulation potential, and accumulation time were found to be 5.69, 562.30 mV, and 64.30 s for the analysis of AMP in samples, respectively. The newly developed voltammetric method for the determination of AMP offers a linear relationship between the peak current and concentration in the range of 1.0 x 10(-8) - 1.0 x 10(-6) M with the correlation coefficient (r = 0.9990) and the detection limit (LOD = 2.97 x 10(-9) M). The lifetime of prepared electrode was also tested, and the current intensity of AMP was nearly stable at least 2 months by using TiO2-CPE. The validity of the method was tested by analyzing standard samples containing the analyzed compound. Under optimized and validated experimental conditions, the proposed method was successfully applied for the quantitative analysis of AMP in commercial tablets.