Electrocatalytic determination of oxalic acid by TiO2nanoparticles/multiwalled carbon nanotubes modified electrode

Abstract

In the present work, a TiO₂ nanoparticles/multiwalled carbon nanotubes composite modified glassy carbon electrode was used for the electrocatalytic oxidation of oxalic acid. The electrochemical behavior of oxalic acid at the modified electrode was investigated by cyclic voltammetry. The results showed a good catalytic activity of the electrode for the electrooxidation of oxalic acid, owing to a substantial decrease in anodic overpotentials and an increase in anodic peak current in comparison with the unmodified electrode. A linear relationship between oxidation peak current and concentration was obtained using the cyclic voltammetry technique for an oxalic acid concentration ranging from 0.1 to 1 mM and from 1 to 100 mM with LOD and R.S.D. of 3.3 × 10⁻⁵ M and 5.1% (n = 5) respectively. The peak current obtained from the cyclic voltammetry is stable even after 50 cycles. Finally the activity of the sensor for oxalic acid determination in spinach was also investigated.