Abstract:
To prevent bacterial growth and ensure food safety, common practice involves the use of nitrite and phosphate salts. Nevertheless, elevated nitrite levels in the body can contribute to the development of stomach and esophageal cancers, while excessive phosphate levels may increase the risk of kidney dysfunction and the onset of osteoporosis. Electrochemical sensing has emerged as a reliable technique for detecting nitrites and phosphates. This study specifically focuses on the use of TiO2-based sensing materials for such detection. The synthesis of nanoparticulate TiO2 and Ag-doped TiO2 was successfully achieved through a solution combustion technique. The composition of the materials was examined using X-ray diffraction (XRD) and X-ray absorption near-edge structure (XANES) methods, revealing a predominant anatase composition. Doping resulted in particle refinement, contributing to an increased specific surface area and enhanced electron transfer efficiency, as indicated in the examination by Electrochemical Impedance Spectroscopy (EIS). Cyclic voltammetry (CV) assessed the electrochemical behavior, demonstrating that in nitrite detection, a significant oxidation reaction occurred at an applied voltage of approximately 1.4V, while in phosphate detection, the main reduction peak occurred at a voltage close to -0.5 V. High sensitivity (0.002 µAµM-1mm-2 for sodium nitrite and 0.0021 µAµM-1mm-2 for potassium phosphate) and low limits of detection (0.0052 mM for sodium nitrite and 0.0045 mM for potassium phosphate) were observed. Experimental results support the potential use of Ag-doped TiO2 as a sensing device for nitrites and phosphates.