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

Abstract

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 Cu2+, Cr6+, Co2+, and Hg2+. 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 Hg2+ and make interact with the surface groups of NCDs to cause fluorescence quenching. The fluorescence intensity and Hg2+ concentration showed a linear response in the range of 0.15–1 mM and 0.16–10.24 μM (R2 = 0.998), and the detection limit was 85.71 nM. The fluorescent sensor was used to determine Hg2+ in environmental waters with satisfactory results.