A ratiometric fluorescence probe based on the N, S co-doped dots and silver nanoclusters for the sensitive detection of Hg2+

Exploring highly sensitive fluorescence probe for mercury ion (Hg2+) determination is of great importance for environment system. In this work, a ratiometric fluorescence probe using N, S co-doped dots (NS-CDs) and silver nanoclusters (AgNCs) were successful constructed for the determination of Hg2+. In ratiometric fluorescent sensing system, as AgNCs was added to NS-CDs, fluorescence intensity at 442 nm can be reduced but in the increase of intensity at the 762 nm. Inner filter effect (IFE) was attributed to the mainly mechanism of action between the NS-CDs and AgNCs. Interestingly, the fluorescence of NS-CDs/AgNCs at 442 nm was gradually increase after the addition of Hg2+, while fluorescence at 762 nm was gradually quenched. Owing to the formation of NS-CDs/Agn-2NCsHg complexes, the NS-CDs/AgNCs led to a significant conformational change of Hg2+. According to the reverse change of two fluorescence peaks (I765/I442), a novel NS-CDs/AgNCs probe was designed for specific recognition of Hg2+ with the linear range from 0.1 to 90 μM and a limit detection (LOD) of 0.041 μM. Besides, NS-CDs/AgNCs was successful implemented to detect Hg2+ in the sample water with the good recoveries of 92.90-103.64% (RSD≤4.62%). Accordingly, the NS-CDs/AgNCs ratiometric fluorescent probe with simplicity, rapidity and high sensitivity exhibited a huge potentiality in the water environment analysis.