Starch-Based Carbon Dots for Nitrite and Sulfite Detection

Nitrite and sulfite play important roles in human health and environmental science, so it is desired to develop a facile and efficient method to evaluate NO(2) (-) and SO(3) (2-) concentrations. In this article, the use of green alternatives with the potential of multi-functionality has been synthesized to detect nitrite and sulfite based on fluorescent probe. The carbon dots (CDs) with starch as only raw materials show fluorescence turn “on-off-on” response towards NO(2) (-) and SO(3) (2-) with the limits of detection of 0.425 and 0.243 μМ, respectively. Once nitrite was present in the solution, the fluorescence of CDs was quenched rapidly due to the charge transfer. When sulfite was introduced, the quenching fluorescence of CDs was effectively recovered because of the redox reaction between NO(2) (-) and SO(3) (2-), and thus providing a new way for NO(2) (-) and SO(3) (2-) detection. Owing to their excellent analytical characteristics and low cytotoxicity, the “on-off-on” sensor was successfully employed for intracellular bioimaging of NO(2) (-) and SO(3) (2-).