A highly selective fluorescence turn-on sensor for Hg²⁺ based on quinolimide in aqueous media and its applications

Herein, a novel fluorescent sensor QPE based on quinolimide was developed, which displayed the highly selective response to Hg²⁺ through the turn-on signal in aqueous media. The corresponding recognition mechanism of QPE for Hg²⁺ was investigated by the titration experiments, Job's plots, HRMS, and DFT calculations analysis. QPE could detect Hg²⁺ in a broad pH range (pH = 4-9) with the LOD of 20 nM and the LOQ of 66 nM. Meanwhile, QPE-loaded test strips were demonstrated in the visual detection of Hg²⁺. Importantly, QPE exhibited the reliable capability to track Hg²⁺ in real water and soil samples and yeast cells, indicating that QPE could be used as a prospective tool for monitoring Hg²⁺ in wide fields.