A novel sensor aluminum silicate modified carbon paste electrode for determination of anti-depressant dothiepin HCl in pharmaceutical formulation and biological fluids

A novel sensor aluminum silicate was used as a cheaper modifier for the rapid and sensitive voltammetric determination of dothiepin HCl (DTP). Cyclic voltammetry, scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), chronoamperometry (CA) and square-wave voltammetry techniques were used to characterize the properties of the sensor. The best results were obtained when the measurements are carried at pH 7 using a Britton-Robinson buffer. Under optimum conditions, the linearity range was 2 x 10(-7)-1 x 10(-4) M with a correlation coefficient equal to 0.9998. LOD and LOQ were determined to be 4 x 10(-8), 12.1 x 10(-8), M respectively. The obtained results were compared successfully with respect to those obtained using the official method. Moreover, this sensor is sensitive for the determination of DTP in the presence of ascorbic acid (AA), uric acid (UA), dopamine (DA) and common interference molecules. The high sensitivity, good reproducibility, and wide linear range make the modified electrode suitable for determination of DTP in pharmaceutical preparation, human serum and urine sample with excellent recoveries. The possible electro-oxidation pathway and the number of transferred electrons were also investigated.