Cyclodextrin-assisted fluorescein decoration of gold nanoclusters for ratiometric and selective Hg2+ analysis

Introduction The construction of nanomaterial-based ratiometric detection systems usually requires covalent modification, which undergoes reactive environments and may change the natural properties of supporting nanomaterials. Methods In this study, dualemissive and fluorescein-decorated gold nanoclusters (F-Au NCs) through cyclodextrin-supported host–guest interaction (non-covalent modification) are explored as ratiometric Hg 2+ nanoprobes through d 10 –d 10 -interactioncaused fluorescence quenching of Au NCs. Results and Discussion The fluorescein decoration only provides a fluorescent internal reference but does not change the Hg 2+ -Au NCs affinity nature. Ratiometric and selective Hg 2+ detection is achieved through the proposed F-Au NC probes with a limit of detection of 15 nM. The Hg 2+ analysis in river water samples with small relative standard deviations validates the practical application of these probes.