A novel approach for non-enzymatic determination of urea via screen-printed electrode prepared with conductive ink containing graphene and nickel oxide

Abstract

Development of conductive inks for the fabrication of flexible sensors designed for the determination of various biological compounds represents a promising approach. In this study, non-enzymatic conductive ink for urea detection is developed using nitrogen-doped graphene and nickel oxide nanoparticles. The screen printing technique was used to prepare a flexible electrochemical paper-based electrode utilizing the conductive ink. In order to create disposable electrodes that exhibit high electrical conductivity and strong integration into the flexible substrate, it is essential to consider the production process and components of the inks. The prepared graphite/NiO/N-doped graphene/screen-printed electrode (G/NiO/N-Gr/SPE) is subjected to a series of electrochemical and morphological characterizations, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FE-SEM). The electrochemical detection of urea was conducted using the G/NiO/N-Gr/SPE. The electrode exhibits a linear range of 0.5 to 1000 μM, with a limit of detection (LOD) of 0.32 μM. This innovative urea sensor demonstrates promising potential for the analysis of urea in saliva and urine samples.