Defect-engineered Co-Fe3N/rGO nanoarchitectures via urea-assisted nitridation for selective detection of gourmet flavorant vanillin in food products.

Vanillin, a widely used flavouring agent in food, pharmaceutical, and cosmetic industries, requires precise monitoring due to potential health risks at excessive consumption. This study reports a highly sensitive electrochemical sensor based on defect-engineered Co-Fe₃N/rGO synthesized via urea-assisted nitridation. This process creates nitrogen vacancies in Co-Fe₃N, while rGO ensures uniform nanoparticle dispersion and enhanced electron transfer. Characterization confirmed 20-50 nm Co-Fe₃N nanospheres anchored on rGO with intimate interfacial contact. The modified electrode exhibited outstanding electrocatalytic activity toward vanillin oxidation, delivering a detection limit of 0.249 nM, a linear range of 0.01-1322 μM, and excellent selectivity. Practical applicability was validated through vanillin quantification in six commercial food products, achieving recoveries of 98.99-101.57% with good agreement to HPLC. The exceptional performance arises from synergistic effects between nitrogen-vacancy active sites and the conductive rGO network. This work presents a robust, cost-effective platform for food quality monitoring with potential for field-deployable applications.