A nitrite electrochemical sensor based on electrodeposition of zirconium dioxide nanoparticles on carbon nanotubes modified electrode

Interaction between Amorphous Zirconia Nanoparticles and Graphite: Electrochemical Applications for Gallic Acid Sensing Using Carbon Paste Electrodes in Wine

Amorphous zirconium oxide nanoparticles (ZrO₂) have been used for the first time, to modify carbon paste electrode (CPE) and used as a sensor for the electrochemical determination of gallic acid (GA). The voltammetric results of the ZrO₂ nanoparticles-modified CPE showed efficient electrochemical oxidation of gallic acid, with a significantly enhanced peak current from 261 µA ± 3 to about 451 µA ± 1. The modified surface of the electrode and the synthesised zirconia nanoparticles were characterised by scanning electrode microscopy (SEM), Energy-dispersive x-ray spectroscopy (EDXA), X-ray powdered diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Meanwhile, the electrochemical behaviour of GA on the surface of the modified electrode was studied using differential pulse voltammetry (DPV), showing a sensitivity of the electrode for GA determination, within a concentration range of 1 × 10⁻⁶ mol L⁻¹ to 1 × 10⁻³ mol L⁻¹ with a correlation coefficient of R² of 0.9945 and a limit of detection of 1.24 × 10⁻⁷ mol L⁻¹ (S/N = 3). The proposed ZrO₂ nanoparticles modified CPE was successfully used for the determination of GA in red and white wine, with concentrations of 0.103 mmol L⁻¹ and 0.049 mmol L⁻¹ respectively.