The design of aggregation-induced fluorescence sensor based on the cetyltrimethylammonium bromide-mediated nitrogen-doped carbon dots for selective detection of Hg2+

This work reported an economical and sensitive fluorescence sensor for mercury (II) ions based on the cetyltrimethylammonium bromide-mediated nitrogen-doped carbon dots (NCDs). The NCDs, obtained by a solvothermal method, exhibit emission with low quantum yield (6%) that can be quenched by various ions such as Cu 2+ , Cr 6+ , Co 2+ , and Hg 2+ . After adding cetyltrimethylammonium bromide (CTAB), the two produced aggregation-induced fluorescence effect, coupled with electrostatic interaction , and the quantum yield increased to 32%. The spatial structure formed by CTAB/NCDs could selectively capture Hg 2+ and make interact with the surface groups of NCDs to cause fluorescence quenching. The fluorescence intensity and Hg 2+ concentration showed a linear response in the range of 0.15–1 mM and 0.16–10.24 μM (R 2  = 0.998), and the detection limit was 85.71 nM. The fluorescent sensor was used to determine Hg 2+ in environmental waters with satisfactory results.