A novel fluorescent ?OFF-ON? sensing strategy for Hg (II) in water based on functionalized gold nanoparticles

Mercury ion (Hg2+) is a heavy metal pollutant that can affect the safety of water environment and endanger human health. A novel detection strategy (GNPs-L-Cys-Rh6G(2)) for Hg2+ based on a fluorescence OFF-ON was proposed. Gold nanoparticles (GNPs) were assembled with L-cysteine (L-Cys), which was used as a bridge to link with rhodamine 6G derivatives (Rh6G(2)). The fluorescence state transition of GNPs-L-Cys-Rh(6)G(2) switching from OFF - ON was observed because Hg2+ opened the spirolactam ring through a catalytic hydrolysis mechanism. The fluorescence signal of the GNPs-L-Cys-Rh(6)G(2) system mixed with Hg2+ in the concentration range of 10-100 mu M was analyzed and determined with a limit of detection (LOD) of 2 mu M (S/N = 3). Moreover, the spiked Hg2+ concentration in real water samples were successfully quantified by GNPs-L-Cys-Rh(6)G(2) , which was in line with the ideal average recovery rate and relative standard deviation. The proposed strategy exhibited high specificity, sensitivity and stability, providing a novel sensing platform for heavy metal ions detection in water environment.

Automated summary

A novel detection strategy based on fluorescence OFF-ON was proposed for the detection of mercury ion in water environment. The system incorporated gold nanoparticles and L-cysteine, and the fluorescence state transition was observed through the catalytic hydrolysis mechanism of Hg2+. The strategy exhibited high specificity, sensitivity, and stability, providing a new sensing platform for heavy metal ions detection in water environment.