Polyoxometalate/reduced graphene oxide modified pencil graphite sensor for the electrochemical trace determination of paroxetine in biological and pharmaceutical media.

Paroxetine is an effective drug for the treatment of depression and stress which has been commonly used in recent years. Because of the widespread use and therapeutic effects of paroxetine, a rapid and sensitive method is needed to determine the trace concentration of paroxetine. Herein, an electrochemical sensor was constructed for the measurement of paroxetine using a modified pencil graphite electrode (PGE). Modification of the PGE was carried out by the reduced graphene oxide/phosphotungstic acid (rGO/PWA) by potentiostatic procedure at -1.2 V for 5 min in phosphate buffer solution with pH = 7.0. Surface morphology analyzing of the modified PGE was performed by scanning electron microscopy (SEM), Raman, XRD, FTIR and electrochemical impedance spectroscopy (EIS) techniques. The kinetic parameter of electron transfer coefficient (α) was calculated for the oxidation process of paroxetine at the modified PGE. Differential pulse voltammetry (DPV) was performed for the determination of PRX. The calibration graph exhibited linear characteristics in the range of 8.0 × 10-9-1.0 × 10-6 M of PRX concentration (R2 = 0.998). The relevant limit of detection was found to be 9.0 × 10-10 M. The modified PGE was successfully performed for the determination of PRX in paroxetine tablets and real samples such as human serum and urine.