Electrochemical determination of paracetamol in pharmaceutical tablet by a novel oxidative pretreated pencil graphite electrode

The present paper reports the preparation of a novel, sensitive, and low-cost electrochemical sensor for the determination of paracetamol (PAR). The main strategy of this study lies on providing the surface of a pencil graphite electrode (PGE) with various oxygen-bearing functional groups by in situ oxidative pretreatment, which enables the PGE with larger surface area to adsorb PAR efficiently and mediates electron transfer. The developed oxidative pretreated PGE (OP-PGE) sensor was used for the first time to determine PAR from pure and commercial tablet dosage forms. Surface morphology of the OP-PGE was characterized by scanning electron microscopy (SEM) and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). Electrochemical behavior of PAR on the OP-PGE was investigated with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimized experimental conditions, the linear dynamic range of calibration was between 0.052–2.85 μM with a detection limit of 18.4 nM (S/N = 3). The OP-PGE showed a good sensitivity, selectivity, and stability compared to the bare PGE. Results revealed that the OP-PGE could successfully determine PAR from the tablets with no tedious electrode fabrication and sample pretreatment methods, and in situ oxidative pretreatment could be an alternative, simple and sensitive approach for the fabrication of PGE-based electrodes to use them in the pharmaceutical analysis in the future studies.