One-step synthesis of dual-emission carbon dots for ratiometric fluorescence sensing of curcumin in food samples

Illegal addition of curcumin (Cur) in food poses a significant public health threat, creating an urgent need for sensitive, reliable detection methods. In this work, dual-emission carbon dots (DCDs) were synthesized via a one-step hydrothermal method with Rose Bengal and melamine as raw materials. Based on the distinct fluorescence responses of DCDs to Cur at two characteristic wavelengths, a novel ratiometric fluorescence sensor for Cur detection was constructed. The emission at 432 nm is primarily governed by inner filter effect, while quenching at 532 nm is associated with the fluorescence resonance energy transfer. The sensor shows a robust linear range of 0.1–20 μM with a limit of detection of 0.089 μM. The sensor was successfully employed for the detection of Cur in various food samples, including chili, ginger, and mustard powder, achieving recovery rates between 92.75% and 110.00%. This work enriches CDs synthesis strategies and provides a sensitive, cost-effective, rapid method for Cur detection, supporting food industry monitoring needs.