Simultaneous Voltammetric Detection of Acetaminophen and Theophylline Using Fe3O4/MWCNTs Nanocomposite Modified Carbon Paste Electrode

A modified carbon paste electrode with Fe3O4 nanoparticles/multi-walled carbon nanotubes nanocomposite (Fe3O4/MWCNTs/CPE) was developed as an efficient sensor for simultaneous determination of acetaminophen (AC) and theophylline (TP). The Fe3O4/MWCNTs nanocomposite was characterized by scanning electron microscopy (SEM), X-Ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). Also, electron transfer rate of [Fe(CN)6]3-/4- as a redox couple probe on the surface of the Fe3O4/MWCNTs/CPE was studied using electrochemical impedance spectroscopy (EIS). The modified electrode preserved and combined the properties of the individual modifiers synergistically. The anodic peak currents of AC and TP were increased at the nanocomposite modified electrode compared to the bare electrode. Under the optimal experimental pH, the linear analytical curves were obtained in the range of 2-1000 µM with a limit of detection (LOD) (S/N=3.0) of 1.68 µM for AC and in the range of 3-1000 µM and with a detection limit of 2.48 µM for TP using the differential pulse voltammetry (DPV) results. The applicability of the proposed method was successfully proved for simultaneous determination of these compounds in drug samples.