Glutathione-protected silver nanoclusters for sensing trace-level Hg2+ in a wide pH range

Abstract

An effective fluorescence method for the selective and rapid determination of trace-level Hg²⁺ in a wide pH range had been proposed based on the glutathione-protected Ag nanoclusters (NCs). Factors affecting the fluorescence intensity of GSH–Ag NCs were investigated. We found that the fluorescence intensity of Ag NCs remained high and stable under pH from 4 to 10, which benefits the monitoring of Hg²⁺ under different pH conditions in real samples. The fluorescence quenching mechanism is also discussed. The fluorescence of Ag NCs could be quenched in the presence of Hg²⁺ with a detection limit as low as 1 nM. Good linear correlations were obtained over the concentration range from 0 to 2.5 μM under different pH values (pH = 7, pH = 4 and pH = 9). In addition, this method was successfully applied to the determination of Hg²⁺ in real samples.