A solid-state sensor based on poly(2,4,6-triaminopyrimidine) grafted with electrochemically reduced graphene oxide: Fabrication, characterization, kinetics and potential analysis on ephedrine

A catalytic surface was fabricated by incorporation of electrochemically reduced graphene oxide (rGO) on poly(2,4,6-triaminopyrimidine) (PTAP) film modified glassy carbon electrode. The surface materials of the constructed electrode (rGO.PTAP/GCE) were characterized by means of electrochemical and surface scanning techniques including Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and X-ray Photoelectrons Spectroscopy (XPS). Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were carried out to identify the preparation of the graphene oxide (GO). The heterogeneous rate constant (k _s = 0.149 cm s ⁻¹ ) of the fabricated sensor was evaluated by Nicholson method. The synergistic effect of surface materials promotes the catalytic efficiency of the developed sensor for the detection of ephedrine (EPH) in pharmaceutical samples where the detection limit (DL _3σ ) of EPH was 1.8 μM (297 ppb). The diffusion coefficient of ephedrine (2.55 × 10 ⁻⁵ cm ² ·s ⁻¹ ) was also evaluated using theoretical electrochemical approach. The analytical performance of the sensor was successfully applied for real drug sample with acceptable analytical recovery percentage.