Copper ions (Cu2+) and sulfur ions (S2-) 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 Cu2+ and S2- 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 Cu2+ detection. The N, F-CDs, based on the redox reactions for selective and quantitative detection of Cu2+, showed a wide linear range (0-200 μM) with a detection limit (215 nM). By forming the N, F-CDs@Cu2+ sensing platform and based on the high affinity of S2- to Cu2+, the N, F-CDs@Cu2+ can specifically detect S2- 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 Cu2+ and S2- detection in environmental water samples, implying the good potential for applications.
Keywords: carbon dots; copper detection; fluorescent probe; sulfide detection.