Electrochemical Detection of Dopamine: Novel Thin-Film Ti-Nanocolumnar Arrays/Graphene Monolayer-Cufoil Electrodes

Deposition at oblique vapor incidence angles can lead to the growth of thin films with dramatically changed morphological features. Herein, thin-film titanium nanocolumnar arrays were grown on a graphene monolayer/copper foil substrate (TiNCs/Gm-Cufoil) by applying a physical vapor deposition method, through magnetron sputtering at an oblique angle. Ti-nanocolumnar arrays with ca. 200 nm length were developed throughout the substrate with different morphologies depending on the substrate topography. It was found that over the as-fabricated electrocatalyst, the electrooxidation reaction of dopamine is facilitated, allowing quasi-reversible electrooxidation of protonated dopamine to dopamine quinone. Additionally, contrary to works that appeared in the literature, TiNCs/Gm-Cufoil also promotes further quasi-reversible oxidation of leucodopaminechrome to dopaminechrome. The electrode exhibited two linear ranges of dopamine detection (10–90 μM with a sensitivity value of 0.14 μAμM−1cm−2 and 100–400 μM with a sensitivity value of 0.095 μAμM−1cm−2), a good stability over time of about 30 days, and a good selectivity for dopamine detection.