Simultaneous Detection of Coexisting Metal Ions by a Sulfur Quantum Dot-Based Sensor Array with Analyses of PCA and HCA

Heavy metal contamination causes a great threat to environmental sustainability and human health, making the simultaneous detection of coexisting heavy metal ions (HMIs) critically important. The advancement of sensor arrays has presented significant potential for the simultaneous identification of multiple coexisting heavy metals by integrating multiple detection channels in a single run. This study investigates a three-channel sensor array composed of three different fluorescent sulfur quantum dots (SQDs) for the sensing of HMIs in environmental samples. The specific interactions between each SQD variant and the target HMIs result in different fluorescence responses. Principal component analysis and hierarchical cluster analysis are employed to process the fluorescence signals, and the results indicate that the seven HMIs are successfully differentiated with an accuracy of 100%. Most importantly, this study demonstrates that a three-channel sensor array can work as an efficient sensing system to precisely detect multiple targets at low concentrations of 5.0-50 μM.