Electrochemical platform using graphitic carbon nitride@carbon black composite for electrochemical sensing of vanillin in commercial food samples: bridging practical sensing with DFT mechanistic insights.

In this work, a disposable, cost-effective electrochemical sensor based on a graphitic carbon nitride (g-C3N4)@carbon black (CB) composite was developed for the electrochemical sensing of the food additive vanillin (VAN). The fluorine-doped tin oxide (FTO) was modified with g-C3N4@CB-based inks via screen-printing. Cyclic voltammetry revealed a range of redox processes of VAN on the composite surface. Periodic density functional theory (DFT) was employed to investigate the properties of bulk materials and the interaction between VAN and the electrode surface, while molecular DFT provided insight into the analyte's redox behavior. The sensor offered a linear range from 0.085 to 16.200 μmol L-1, a detection limit of 3 nmol L-1, excellent stability, repeatability, and specificity. The method was implemented to detect VAN in commercial food products. The paired t-test showed no statistically significant difference between the proposed platform and the HPLC-DAD method, demonstrating the sensor's high potential for VAN sensing in food.