Nitrogen-defect-driven rGO tailored terbium vanadate nanorices as an electrochemical platform for carbendazim detection in food extracts with DFT insights.

The prompt and accurate identification of carbamate fungicides in food has emerged as a crucial concern. Here, we developed zircon-type terbium vanadate intertwined nitrogen-doped reduced graphene oxide (TbVO4@N-rGO) nanocomposite through ultrasonication for electrochemical detection of carbendazim. Comprehensive structural and surface analyses validate the formation of pure, crystalline TbVO4 phase with a unique nanorice morphology. The superior sensing performance arises from N-doped rGO, which enhanced conductivity and promotes CBZ adsorption through π-π stacking interactions combined with catalytic active sites of TbVO4 nanorices and defect-driven charge transfer. The modified electrode exhibits a low limit of detection of 1.44 nM, linear range 0.01-1793 μM and high sensitivity of 1.605 μA/μM cm2). Furthermore, DFT calculations provide the optimized structure of CBZ, its electrostatic potential, and HOMO-LUMO energy gap providing ionization potential (I = -HOMO) of 6.1 eV and electron affinity (A = -LUMO) of 0.85 eV. The sensor also exhibited excellent selectivity >5-fold over interferents, stability and reproducibility. When applied to real-world food matrix samples, carrot juice with recovery ranges of 97.11-98.94% (R2 = 0.9913) and 97.37-100.30% (R2 = 0.9901). Thus, TbVO4@N-rGO serves as an efficient electrocatalyst for the sensitive accurate detection of CBZ, contributing to improved food quality control.