A highly selective dual-signal ratiometric fluorescence sensing strategy for brilliant blue in food based on carbon dots/copper nanoclusters nanocomposite

Brilliant blue (BB), a synthetic dye commonly used as a food coloring agent and in pharmaceutical formulations, poses significant health risks when consumed excessively. Prolonged or high intake of BB has been linked to potential toxicity, including disruptions in metabolic pathways and adverse effects on organ function, particularly the liver. In this study, a stable dual-emission sensor, consisting of carbon dots and copper nanoclusters, was designed for the highly selective detection of BB, utilizing the inner filter effect. When excited at 380 nm, this sensor displays distinct emission peaks at 430 nm and 640 nm. Upon addition of BB, the emission at 640 nm is significantly quenched, and the fluorescence intensity ratio (F 640 /F 430 ) displays a linear relationship with BB concentrations ranging from 1 to 1000 nmol/L, with a detection limit of 1 nmol/L. The probe was successfully applied for detecting BB in real samples, with recoveries ranging from 94.8 % to 108.8 % and a relative standard deviation of less than 2.2 %.