Photo-Electrochemical Sensing of Dopamine by a Novel Porous TiO₂ Array-Modified Screen-Printed Ti Electrode.

In this paper, the development of a nanoporous TiO₂ array-modified Ti electrode for photo-electrochemical (PEC) sensing of dopamine (DA) is reported. A porous TiO₂ array-modified electrode was fabricated from the controlled anodic oxidation of a Ti working electrode of commercial screen-printed electrodes (SPE). The anodization process and the related morphological and microstructural transformation of the bare Ti electrode into a TiO₂/Ti electrode was followed by scanning electron microscopy (SEM) and UV-visible reflectance spectroscopy (DR-UV-Vis). The modified electrode was irradiated with a low-power (120 mW) UV-Vis LED lamp (λ = 400 nm) and showed good performance for the detection of DA with a large linear response range, a sensitivity of 462 nA mM-1 cm-2, and a limit of detection of 20 µM. Moreover, it showed higher photocurrents in the presence of DA in comparison to some foreign species such as ascorbic acid, uric acid, glucose, K⁺, Na⁺, and Cl-. Thus, this proposed low-cost photo-electrochemical sensor, with the advantage of very simple fabrication, demonstrates potential applications for the determination of dopamine in real samples.