writer：Wen-Jun Niu, Dan Shan*, Rong-Hui Zhu, Sheng-Yuan Deng*, Serge Cosnier, Xue-Ji Zhang
keywords：CQDs; AuNCs; CQDs/AuNCs nanohybrid; ratiometric fluorescent sensor; cadmium (II) ions; l-ascorbic acid
source：期刊
specific source：Carbon
Issue time：2015年

In this work, for the first time, a novel carbon quantum dots (CQDs) based ratiometric fluorescent probe for sensitive and selective sensing of cadmium (II) ions and l-ascorbic acid (AA) has been established. The blue emissive CQDs, prepared by a one-step hydrothermal treatment with alanine and histidine, play the role of reference fluorophore. The red emissive gold nanoclusters (AuNCs), capped by 11-mercaptoundecanoic acid (MUA), serve as a specific recognition element. Different from MUA-capped AuNCs, the proposed CQDs/AuNCs nanohybrid exhibits high selectivity and sensitivity to cadmium (II) ions with a detection limit of 32.5 nM, which is attributed to the static quenching and the inner filter effect (IFE) of Cd2+ to CQDs/AuNCs nanohybrid. Unbelievable, in the presence of AA, the above-quenched sensor is recovered gradually. The proposed fluorescence sensor displays an enhanced performance for AA determination with the linear range up to 15 mM and the detection limit down to 0.105 ?M. More importantly, this fluorescent “on-off-on” method also offers the excellent performance to Cd2+ and AA detection in lake water and in human serum, respectively.