A Photoelectrochemical Sensor Based on Anodic TiO₂ for Glucose Determination

A simple photoelectrochemical (PEC) sensor based on non-modified nanostructured anodic TiO₂ was fabricated and used for a rapid and sensitive detection of glucose. The anodic TiO₂ layers were synthesized in an ethylene glycol-based solution containing NH₄F (0.38 wt.%) and H₂O (1.79 wt.%) via a three-step procedure carried out at the constant voltage of 40 V at 20 °C. At the applied potentials of 0.2, 0.5, and 1 V vs. saturated calomel electrode (SCE), the developed sensor exhibited a photoelectochemical response toward the oxidation of glucose, and two linear ranges in calibration plots were observed. The highest sensitivity of 0.237 µA µmol^-1 cm^-2 was estimated for the applied bias of 1 V. The lowest limit of detection (LOD) was obtained for the potential of 0.5 V vs. SCE (7.8 mM) with the fastest response at ~3 s. Moreover, the proposed PEC sensor exhibited relatively high sensibility, good reproducibility, and due to its self-cleaning properties, a good long-term stability. Interfering tests showed the selective response of the sensor in the presence of urea and uric acid. Real-life sample analyses were performed using an intravenous glucose solution, which confirmed the possibility of determining the concentration of analyte in such types of samples.