A smart luminescent metal-organic framework-based logic system for simultaneous analysis of copper ions and hydrogen sulfide
Simultaneous detection of multiple targets is in imperative demand but challenging for analysis technology. In this study, a novel multi-input luminescent logic system based on a nanoscale Zr(IV)/Eu(III) metal-organic framework (Zr-pydc-Eu) is designed for simultaneous identification and quantification of copper ion and hydrogen sulfide, which are considered to be not only the toxic species in environment but also associated with various physiological and pathological processes in human body. In the MOF-based logic gate, the pyridine-2,5-dicarboxylic acid (pydc) behave as both the energy donor and metal-chelating site, the photoactive Eu3+ ions function as the luminescence signal reporter/output, and the target analytes (Cu2+ and H2S) serve as energy modulators/inputs. By using the specific Cu2+ as a single input among various metal ions, the NOT logic operation is realized in Zr-pydc-Eu with the output swithcing from “1” to “0”. With the sequential restored output from “0” to “1” by H2S input over the biologically relevant species, the IMPLICATION logic gate is implemented. Such features enable this Zr-pydc-Eu logic system to be an effective and smart platform for analyzing both Cu2+ and H2S with low detection limit (10-8 M) and real-time response (< 2 min), presenting significant potentials for multiplex analysis application in human health monitoring.