Graphene/gadolinium oxide composite modified screen-printed electrochemical sensor for detection of diclofenac sodium

This study investigates the electrochemical sensing of diclofenac sodium. A bare single screen-printed carbon electrode was modified with graphene/gadolinium (III) oxide (Gd2O3) where graphene serves as the conductive support material for the electrode. The interaction between the elements of graphene/Gd2O3 composite and diclofenac with graphene/Gd2O3 composite has been studied by density functional theory (DFT). The characterization of the nanocomposite underwent through some sophisticated characterization techniques like field-emission scanning electron microscopy (FE-SEM), Energy Dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD). Electrochemical techniques like cyclic voltammetry (CV) were used for studying the chemical kinetics and absorbance of the nanocomposite while Differential Pulse Voltammetry (DPV) was used to study the oxidation of Diclofenac. The electrochemical studies exhibit a linear range of detection from 5.89 µM to 66.7 µM concentration of the analyte. Importantly, in-silico studies based on the semi-empirical (PM6) approach strongly favoured the experimental outcomes especially, the binding features involved the both the dimer complex versus the trimer complex. The binding energy of the three components-based model (Graphene-Gd2O3-Diclofenac) has been calculated to be extremely larger than that of the two components-based model (Graphene-Diclofenac). This novel Diclofenac biosensor showed satisfactory results and it has the potential to create a great platform in the environmental monitoring system.