Paper-based biosensor for glucose and paracetamol sensing using chitosan/ graphene oxide modified electrode

This work presents the development of chitosan/ graphene oxide modified paper-based electrode for electrochemical sensing of glucose and paracetamol. Preparation of the modified paper-based electrode was described, and several characterizations using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) were carried out to evaluate the physical, electronic, and microstructural properties of chitosan/ graphene oxide layer. The electrochemical performance of the modified electrode was evaluated preliminary using impedance spectroscopy, and the electrochemical detection of both glucose and paracetamol in simulated urine was assessed using cyclic voltammetry (CV). Impedance data reveals that the electron transfer mechanism at the electrode/ analyte solution interface occurs faster with increasing concentration of the analyte. CV-based measurements exhibit a linear response for analyte concentration ranging between 2.5 and 100 µM. In addition, irrespective of the analyte, the sensitivity increases with an additional fraction of graphene oxide in the modified paper-based electrode. The highest sensitivity for glucose sensing is 4.4 mA.mM^-1, while the highest sensitivity for paracetamol sensing is 16 mA.mM^-1, by using electrode coated with chitosan/ graphene oxide (5%,%w) composites.