Facile preparation of fluorescent gold nanocluster via polysaccharide-templated approach and its application for Cu2+ sensing

In this report, we have constructed a simple, eco-friendly and one-pot synthetic strategy for the synthesis of fluorescent gold nanoclusters (GNCs) using a native polysaccharide (chondroitin sulfate) as the novel template. Moreover, we used some analytical instruments for characterizing the formation of Au clusters, containing ultraviolet-visible spectrometer, fluorescence spectrometer, high resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectroscopy (XPS). The obtained data indicated that the Au nanoclusters were successfully formed. The chondroitin sulfate-capped gold nanoclusters (CS-GNCs) displayed excitation and emission bands at 450 and 520 nm, respectively. The fluorescence quantum yield was 4.78%. We further used CS-stabilized gold nanoclusters selectively and sensitively for sensing Cu2+ in real samples via non-covalent d10-d10 metallophilic bond. The linear range of the method was 0.01–1.8 μM with the limit of detection (LOD) was 8 nM (signal/noise = 3), and the recoveries of the spiked samples in lake water and tap water samples ranged from 90% to 108%, suggesting that the proposed method could be used in the practice detection of Cu2+.