Nitrogen and phosphorus doped polymer carbon dots as a sensitive cellular mapping probe of nitrite

Nitrite (NO2−) is one of the important pollutants in food and the environment, which can seriously endanger the health of human beings. Therefore, detecting nitrite in food, environmental and biological samples is very significant for health monitoring. Herein, polymer carbon dots (PCDs) doped with nitrogen and phosphorus were prepared by polymerization of ascorbic acid (AA) and polyethylenimine (PEI) with phosphoric acid, and exhibited excellent stability, adjustable fluorescence emissions and good biocompatibility. It was found that the PCDs presented a sensitive response to nitrite (NO2−), and they were successfully applied for NO2− analysis in water and milk samples, and the dynamic monitoring of nitrite entry into Hep-2 cells.