Cytidine-stabilized copper nanoclusters as a fluorescent probe for sensing of copper ions and hemin

We reported a sensitive and selective fluorescence turn on-off strategy for detection of Cu2+ and hemin, respectively. The fluorescence turn on sensor for Cu2+ detection had a wide linear range of 0.05-2.0 mu M with a limit of detection (LOD) of 0.032 mu M, and the fluorescence turn off sensor for hemin detection possessed a wide linear range of 0.05-4.0 mu M with an LOD of 0.045 mu M. The sensor for Cu2+ or hemin exhibited high selectivity over other possible substances. In addition, it was demonstrated by using various analytical characterization techniques that the fluorescence turn on sensor for Cu2+ was constructed on the basis of the formation of water-soluble fluorescent copper nanoclusters (CuNCs), and the fabrication of the fluorescence turn off sensor for hemin was predominately based on the inner filter effect of hemin on the fluorescence of the CuNCs. Finally, the proposed fluorescence turn on-off sensor system was successfully applied for detection of Cu2+ in lake water samples and hemin in duck blood samples.