Ratiometric fluorescent platform for on-site monitoring of sodium pyrosulfite in preserved fruits.

The rapid detection of pyrosulfites in food chemistry is crucial to food safety and health. Here, a coumarin-type ratiometric fluorescent probe was developed based on the Michael addition reaction to detect sodium pyrosulfite (NaSO). The probe exhibited high selectivity and fast response (t = 6 s) to NaSO and a low detection limit (26 nM). Because of its excellent ratiometric response performance, the probe was successfully applied to measure the amount of NaSO in preserved fruits. Colour information analysis and formula calculations were performed to quickly determine the sodium pyrosulfite amount in an actual sample by using a smartphone. Therefore, the intelligent strategy of combining the sensing process and smartphone provides a convenient and efficient method for the fast monitoring of sodium metabisulfite in actual food.