Amino-functionalized HPU-23@Ru@Tb as light-driven oxidase-like nanozyme for colorimetric recognition of Hg²⁺ and ratiometric fluorescence sensing of ClO⁻ and PO₄³⁻

A HPU-23@Ru@Tb-NH₂ sensor array with light-driven oxidase-mimicking activity and triple-emission fluorescence was developed. It was composed of a Tb³⁺-functionalized metal organic framework and Ru(bpy)₃²⁺ and applied to the simultaneous detection of Hg²⁺, ClO⁻, and PO₄³⁻ via differently responsive channels. HPU-23@Ru@Tb-NH₂ had a photoresponsive colorimetric response toward Hg²⁺ with a LOD as low as 4.18 nM. In addition, the three emissions of the HPU-23@Ru@Tb-NH₂ sensor array were influenced by ClO⁻ and PO₄³⁻ to varying degrees, causing remarkably distinguishable responses for the fluorescence channels to discriminate ClO⁻ and PO₄³⁻ from each other. The detection limits of ClO⁻ and PO₄³⁻ were 12.26 µM and 0.197 nM, respectively. Therefore, this work demonstrates the feasibility of multi-emission and multi-mode sensing platform, which is able to combine the advantages of different strategies for solving the problems of various toxic substances coexisting in the environment while meeting the needs of accurate and precise results and no side interferences.