Synergistic FeCo alloy sites in spherical hierarchical porous carbon boosting ultrasensitive detection of sunset yellow in beverages.

Sunset Yellow (SY), a widely utilized synthetic food colorant, poses potential health risks upon excessive consumption. This work reports an ultrasensitive electrochemical sensor for the quantification of SY in commercial beverages. A spherical hierarchical porous carbon composite embedded with FeCo alloy nanoparticles (FeCo@HPC) was synthesized via sequential hydrothermal carbonization and pyrolysis. Density functional theory (DFT) simulations confirm that FeCo bimetallic synergy enhances interfacial electron transfer kinetics, while the hierarchical porous architecture and nitrogen-doped defect sites cooperatively facilitate SY adsorption and electrocatalytic conversion. The sensor demonstrates a linear response across 0.005-6 μM SY, achieving a detection limit of 2.1 nM (S/N = 3) and sensitivity of 23.6 μA·μM-1. Validation via high-performance liquid chromatography (HPLC) yielded recovery rates of 97.2-103.5 % in spiked beverage matrices. This study establishes a cost-effective analytical platform for food additive surveillance while elucidating design principles for bimetallic carbon-based electrocatalysts.