Carbon dots based dual-emission silica nanoparticles as ratiometric fluorescent probe for nitrite determination in food samples.

In this work, a simple and effective strategy for designing a ratiometric fluorescent nanosensor was described. A carbon dots (CDs) based dual-emission nanosensor for nitrite was prepared by coating the CDs on to dye-doped silica nanoparticles. Dual-emission silica nanoparticles fluorescence was quenched in sulfuric acid using potassium bromate (KBrO). The nitrite present catalyzed the KBrO oxidation, resulting in ratiometric fluorescence response of the dual-emission silica nanoparticles. Several important parameters affecting the performance of the nanosensor were investigated. Under optimized conditions, the limit of detection was 1.0 ng mL and the linear range 10-160 ng mL. Furthermore, the sensor was suitable for nitrite determination in different food samples.