A colorimetric and fluorescent dual-readout probe based on red emission carbon dots for nitrite detection in meat products

Nitrite (NO2-) is widely present in the human environment and accurate, sensitive and selective detecting of nitrite is of vital significance for food safety and water quality. Herein, a novel red emission carbon dots (r-CDs) fluorescent probe was fabricated for dual-mode detection of nitrite, which was capable of both convenient colorimetric analysis and accurate fluorometric detection. When NO2- is added to the rose-red r-CDs solution, NO2- interacts with the amino groups which on the surface of r-CDs to form diazotized substance, resulting in that the colorimetric color of r-CDs solution realizes the transition from rose red to light purple, and the red fluorescence is gradually quenched. The detection limits of colorimetric and fluorescence for NO2- were 0.193 μM and 0.149 μM, respectively. Furthermore, the dual-readout probe revealed satisfactory recovery and reliability when analyzing the concentration of NO2- in ham and bacon samples..