Silver nanoclusters functionalized with Ce(III) ions are a viable "turn-on-off" fluorescent probe for sulfide.

The authors show that silver nanoclusters functionalized with Ce(III) ions are a viable fluorescent probe for selective and sensitive detection of sulfide at pH 7.0. The blue fluorescence of silver nanoclusters (with excitation/emission peaks at 358/426 nm) is enhanced on the addition of Ce(III) ions but is quenched in the presence of a trace concentrations of sulfide. A fluorometric assay was worked out using the Ce(III)/AgNCs as the probe. Sulfide can be detected in concentrations up to 2.0 μM, and the detection limit is 15 nM. The method was successfully applied to the determination of sulfide in spiked real samples. Graphical abstract Silver nanoclusters functionalized with Ce(III) ions are a viable "turn-on-off" fluorescent probe for selective and sensitive detection of sulfide at pH 7.0.