Water-soluble gold nanoclusters-based fluorescence probe for highly selective and sensitive detection of Hg2+

L-Amino acid oxidase (LAAOx) capped gold nanoclusters (LAA0x-AuNCs) were prepared by "one-pot" method in aqueous solution. LAAOx-AuNCs showed red fluorescence emission, and this red fluorescence can turn blue in the presence of Hg2+, which is attributed to the effective fluorescence quenching by the strong Hg2+ -Au+ interaction. Among various metal ions studied, Cu2+ ion, like Hg2+, was also found to efficiently quench the fluorescence intensity of LAAOx-AuNC5. However, we noted that ethylenediaminetetraacetate (EDTA) could recover the quenched fluorescence of LAAOx-AuNC5 by Cu2+, but not that by Hg2+. Based on this behavior, LAAOx-AuNCs has been used as a probe to develop a rapid, highly selective and sensitive method for Hg(2+)detection. The response of the probe to Hg2+ exhibited a good linearity in the concentration range of 4.95 x 10(-7)-8.36 x 10(-6) MOI L-1 and 1.50 x 10(-5)-2.20 x 10(-5) MOI L-1, respectively. The detection limit was 58 nM Hg2+. Moreover, the applicability of our detection system is also verified by analysis of Hg2+ in tap water and river water. (C) 2015 Elsevier B.V. All rights reserved.