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 (KBrO3). The nitrite present catalyzed the KBrO3 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-1 and the linear range 10-160 ng mL-1. Furthermore, the sensor was suitable for nitrite determination in different food samples.
Keywords: Food samples; Nitrite; Ratiometric fluorescent probe; Silica nanoparticles.
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