Glutathione-stabilized Cu nanocluster-based fluorescent probe for sensitive and selective detection of Hg2+ in water

In this paper, an innovative and facile one-pot method for synthesizing water-soluble and stable fluorescent Cu nanoclusters (CuNCs), in which glutathione (GSH) served as protecting ligand and ascorbic acid (AA) as reducing agent was reported. The resultant CuNCs emitted blue-green fluorescence at 440 nm, with a quantum yield (QD) of about 3.08%. In addition, the prepared CuNCs exhibited excellent properties such as good water solubility, photostability and high stability toward high ionic strength. On the basis of the selective quenching of Hg 2+ on CuNCs fluorescence, which may be the result of Hg 2+ ion-induced aggregation of the CuNCs, the CuNCs was used for the selective and sensitive determination of Hg 2+ in aqueous solution. The proposed analytical strategy permitted detection of Hg 2+ in a linear range of 4 × 10 −8 to 6 × 10 −5 M, with a detection limit of 2.2 × 10 −8 M. Eventually, the practicability of this sensing approach was confirmed by its successful application to assay Hg 2+ in tap water, Lotus lake water and river water samples with the quantitative spike recoveries ranging from 96.9% to 105.4%.