Dual-emission Si dots-based sensing array for identification of metal ions

Achieving rapid recognition and sensitive detection of multiple heavy metal ions simultaneously is of great significance for the monitoring of public health and environment. Herein, a fluorescence sensing array was constructed using Si dots with two emission centers for efficient discrimination of seven metal ions. Each metal ion had different binding capacities with -OH/-NH₂ groups present on the surface of Si dots and thereby resulting in different changes in fluorescence intensity of the two emission peaks. The changes in fluorescence signals were transformed into unique "fingerprints" and "Euclidean distances" through linear discriminant analysis and hierarchical cluster analysis. The constructed sensing array provided multi-dimensional information to distinguish seven metal ions through a single material and a signal mode and show good linearity for individual metal ion and good performance in the discrimination of metal mixtures, effectively reducing the cost and response time and simplifying the experimental process. This system achieved accurate discrimination of metal ions in actual water samples and has broad application prospects in environmental monitoring.