The synthesis of novel fluorescent bimetal nanoclusters for aqueous mercury detection based on aggregation-induced quenching†
In this research, new bimetal nanoclusters (DAMP–AuAg BNCs) with 4,6-diamino-2-mercaptopyrimidine (DAMP) as a reducing agent and stabilizer ligand were exploited. The nanoclusters displayed excellent fluorescent properties, very small size, good stability, and water solubility. It was found that the as-prepared DAMP–AuAg BNCs exhibited strong fluorescent emission at 640 nm under an excitation wavelength of 473 nm with a large Stokes shift of 167 nm, and the red fluorescence could be readily quenched with aqueous Hg2+. The DAMP–AuAg BNCs showed good specificity and sensitivity toward Hg2+ in aqueous solution, and the fluorescence analysis of Hg2+ showed a wide linear range from 0.85 μM to 246 μM and a detection limit of 20 nM. It is demonstrated that strong Hg2+–Au+ interactions led to the aggregation of nanoclusters, which caused the quenching of the fluorescence, and the affinity of Hg2+ for nitrogen should also be considered. Due to the relevant good performance of DAMP–AuAg BNCs, they were applied to the fluorescence analysis of Hg2+ in real water samples and were found to be a potential fluorescent sensor for aqueous mercury ions.