Sensitive detection of cadmium ions based on a quantum-dot-mediated fluorescent visualization sensor.

A sensitive ratiometric fluorescent sensor for detecting cadmium ions (Cd) was constructed based on carbon quantum dots (CQDs)/CdTe quantum dots (CdTe QDs). Red fluorescence (from CdTe QDs) played the role of the signal response and blue fluorescence (from CQDs) served as a reference probe without a color change. The fluorescent sensor showed high selectivity and sensitivity to Cd with a limit of detection (LOD) of 0.018 μM and a range from 0.1 μM to 23 μM. The proposed method was successfully applied to the determination of Cd in real rice samples. In addition, a fluorescent sensor integrated with a smartphone platform was further designed for the visualized and quantitative detection of Cd. This work might extend the range of visualization analysis strategies and provide new insights into the rapid quantitative, portable and sensitive detection of Cd in real-time and on-site applications.