Interfacial engineering of TiO–WO@MWCNTs nanocomposites for ultrasensitive and highly selective electrochemical nitrite sensing in food samples

Source: PubMed Central Open Access, NCBI / U.S. National Library of Medicine

Nitrite ions are extensively utilized in the food industry to enhance preservation, flavor, and colorants; however, their excessive intake poses serious health risks, including mutagenic and carcinogenic effects. In this work, a novel electrochemical sensor platform providing high sensitivity and high selectivity was constructed using TiO–WO@MWCNTs-modified carbon paste electrodes (CPEs). The synergistic combination of TiO–WObi-metal oxide nanostructures with multi-walled carbon nanotubes significantly enhanced electrochemical reactivity and electrocatalytic activity of the electrode interface. The fabricated nanocomposite was systematically characterized through Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) to identify all acquired features. After assay optimization and mechanistic investigation, the modified electrode exhibited an ultralow detection limit of 0.003 µM and a wide linear detection range of 0.01–210 µM for nitrite detection using chronoamperometry, with excellent selectivity. The sensor's practical applicability was validated through analysis of real food samples, yielding high recovery values and confirming its accuracy and reliability. Schematic workflow of a portable TiO–WO@MWCNTs nanostructured electrochemical platform for sensitive detection and quantification of free nitrite ions (NO) in food samples. toc