Tetrachromic InP/ZnS quantum dots-based fluorescent sensor arrays for accurate discrimination of multiplex metal ions

Accurate identification of multiple teas based on the difference in their contents and species of metal ions is vital in food inspection and public health. However, achieving accurate sensing from one material with various transduction signals and excellent anti-interference remains a challenge. Herein, a four-channel sensing platform was constructed by combining with four water-soluble InP/ZnS QDs with independent emission. The fluorescence intensities of the four water-soluble InP/ZnS QDs change in different degrees owing to the synergistic coordinative effect between metal ions and ligands. Interestingly, the multi-channel sensing platform allows the qualitative performance of metal ions with excellent anti-interference, high sensitivity, and high accuracy in binary and ternary mixtures. Moreover, the multi-channel fluorescent array exhibited a universality-powerful capability for identifying five teas with satisfactory results. The universal application for detecting Cr 6+ , Hg 2+ , and Cu 2+ in various tea drinks was demonstrated with excellent recovery, indicating a promising potential application in food safety.