Carbon-Pt Nanoparticles Modified TiO₂ Nanotubes for Simultaneous Detection of Dopamine and Uric Acid

The present work describes sensing application of modified TiO₂ nanotubes having carbon-Pt nanoparticles for simultaneous detection of dopamine and uric acid. The TiO₂ nanotubes electrode was prepared using anodizing method, followed by electrodeposition of Pt nanoparticles onto the tubes. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. The C-Pt-TiO₂ nanotubes modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry methods. The modified electrode displayed high sensitivity towards the oxidation of dopamine and uric acid in a phosphate buffer solution (pH 7.00). The electro-oxidation currents of dopamine and uric acid were linearly related to the concentration over a wide range of 3.5 × 10⁻⁸ M to 1 × 10⁻⁵ M and 1 × 10 ⁻⁷ M to 3 × 10⁻⁵ M respectively. The limit of detection was determined as 2 × 10⁻¹⁰ M for dopamine at signal-to-noise ratio of 3. The interference of uric acid was also investigated. Electro-oxidation currents of dopamine in the presence of fix amount of uric acid represented a linear behaviour towards successive addition of dopamine in range of 1 × 10⁻⁷ M to 1 × 10⁻⁵ M. Furthermore, in a solution containing dopamine, uric acid and ascorbic acid the overlapped oxidation peaks of dopamine and ascorbic acid could be easily separated by using C-Pt-TiO₂ nanotubes modified electrode.