Highly sensitive simultaneous detection of mercury and copper ions by ultrasmall fluorescent DNA-Ag nanoclusters

摘要

Fluorescent metal nanoclusters (NCs) have given rise to a new class of fluorescent nanomaterials for the detection of heavy metals. Here, we design a simple, rapid and highly sensitive sensing nanosystem for the detection of Hg~(2+) and Cu~(2+) based on fluorescence quenching of ultrasmall DNA-Ag NCs. The fluorescence intensity of DNA-Ag NCs was selectively quenched by Hg~(2+) and Cu~(2+), and the limit of detection (LOD) was found to be 5 nM and 10 nM, respectively. The technique was renewably employed by EDTA addition and successfully applied to detection of Hg~(2+) and Cu~(2+) in domestic water samples. The quantum yield (QY) of DNA-Ag NCs was significantly higher (~30%) compared to traditional water-soluble fluorescent metal NCs. The DNA-Ag NCs detection system is potentially suitable for detecting Hg~(2+) and Cu~(2+) and monitoring water quality in a wide range of samples regulated under the Environmental Protection Agency.