Novel red emission fluorescent carbon dots with narrow-bandwidth emission for nitrite detection in foods and cell...

Nitrite (NO₂^-) is widely present in water and commonly used in food products. Excessive ingestion of NO₂^- poses significant hazards to human health. Therefore, the development of accurate and sensitive nitrite detection methods is greatly essential for public health safety. Herein, novel red-emitting carbon dots (r-CDs) with a narrow emission width (45nm) were prepared through a simple hydrothermal reaction. The fluorescence of r-CDs at 628 nm could be directly and gradually quenched by NO₂^-_. Thus, a highly sensitive and selective nitrite sensing platform was constructed with a wide linear concentration range of 3-200 µM and a detection limit of 0.85 µM. Satisfactory detection performance of NO₂^- was verified in meat, water, milk, and pickled vegetable samples. Furthermore, this probe was successfully applied in distinct fluorescence imaging, exhibiting great potential for the intracellular analysis of NO₂^-. In conclusion, this narrow-emission NO₂^- sensor features facile synthesis, good anti-interference capability, and a wide application scope.