Multifunctional fluorescence sensor based on nitrogen-doped carbon dots and its application for toxoflavin detection

In recent years, food-borne pathogen Pseudomonas cocovenenans have caused many food safety incidents. Therefore, the detection of toxoflavin produced by the bacteria has aroused widespread attention. In this study, two fluorescent sensors were prepared using nitrogen-doped carbon dots (NCDs) materials as precursors: (1) Luminol-functionalized NCDs were synthesized by NHS-EDC reaction, and L-NCDs fluorescence sensor was constructed for the detection of toxoflavins in actual food samples. The linear range of the L-NCDs fluorescence sensor is 0.1–50 μM, the detection limit is 0.05 μM and the excitation wavelength is 375 nm. (2) The NCDs-CMC fluorescent film sensor was constructed by incorporating NCDs into sodium carboxymethyl cellulose. It was excited at a wavelength of 385 nm for visual detection of toxoflavin. The film sensor has a linear range of 1–60 μM and a detection limit of 0.45 μM. The results showed that the method has good sensitivity and reliability. This study extends the application of NCDs-based fluorescence sensing to detect toxoflavin. It enables simple, rapid, low-cost sensitive detection and visual monitoring of toxoflavin. Additionally, it offers a fast and convenient new technology for preventing and controlling Pseudomonas cocovenenans contamination in food.