Adenosine-stabilized Copper Nanocluster as Fluorescent Probe for Detection of Au(III) Ion and Cysteine

A fluorescent "turn-off-on" sensor was constructed for detection of Au(III) ions and cysteine on the basis of fluorescence quenching of adenosine-stabilized copper nanocluster by Au(III) ions and cysteine-induced fluorescence enhancement of the adenosine-stabilized copper nanocluster/Au(III) system. The adenosine-stabilized copper nanocluster-based sensor gave a linear range of 0. 05-10 mu mol/L with detection limit of 0. 02 mu mol/L, and the adenosine-stabilized copper nanocluster/Au(III)-based sensor provided a linear range of 5-60 mu mol/L with detection limit of 1. 6 mu mol//L. In addition, the results showed that the fluorescence quenching of adenosine-stabilized copper nanocluster by Au(III) ion was mainly originated from the super amplification static quenching effect, and the fluorescence enhancement of the adenosine-stabilized copper nanocluster/Au(III) by cysteine mainly arose from the complex reaction between cysteine and Au(III) and the removal of Au(III) on the adenosine-stabilized copper nanocluster/Au(III) system. Additionally, the fluorescence sensor for Au(III) ions and cysteine possessed high selectivity, and could be successfully used for detection of Au(III) ions in water samples and cysteine in pharmaceutical preparations.