Bifunctional Nitrogen and Fluorine Co-Doped Carbon Dots for Selective Detection of Copper and Sulfide Ions in Real Water Samples.

Copper ions (Cu) and sulfur ions (S) are important elements widely used in industry. However, these ions have the risk of polluting the water environment. Therefore, rapid and quantitative detection methods for Cu and S are urgently required. Using 2,4-difluorobenzoic acid and L-lysine as precursors, nitrogen and fluorine co-doped dots (N, F-CDs) were synthesized in this study via a hydrothermal method. The aqueous N, F-CDs showed excellent stability, exhibited satisfactory selectivity and excellent anti-interference ability for Cu detection. The N, F-CDs, based on the redox reactions for selective and quantitative detection of Cu, showed a wide linear range (0-200 μM) with a detection limit (215 nM). By forming the N, F-CDs@Cu sensing platform and based on the high affinity of S to Cu, the N, F-CDs@Cu can specifically detect S over a linear range of 0-200 μM with a detection limit of 347 nM. In addition, these fluorescent probes achieved good results when used for Cu and S detection in environmental water samples, implying the good potential for applications.