Sensitive and rapid fluorescent detection of metronidazole based on stable light-emitting vinylene-linked covalent organic framework.

Development of ultra-sensitive and rapid fluorescent nanoprobe for quantitative and targeted monitoring of metronidazole is of crucial practical significance, but is of great challenge. Herein, a vinyl-linked covalent organic frameworks (sp-BNTP-COF) was fabricated via integrating the 1,3,5-tris-(4-formylphenyl) triazine with 5,5'-bis(cyanomethyl)-2,2'-bipyridine into the skeleton. As-obtained sp-BNTP-COF exhibited excellent luminescence characteristics with an absolute fluorescence quantum yield of 8 %. However, fluorescent emission of sp-BNTP-COF could be sharply quenched via metronidazole based on internal filtration effect. A sensitive fluorescent strategy was built for targeted monitoring of metronidazole. Furthermore, the analysis operation could be accomplished within 20 s, which was desirable for point-of-care monitoring of metronidazole. Therefore, this work not only provides a reliable method for the sensitive, rapid, and quantitative detection of metronidazole residues based on the sp-BNTP-COF, but also paves the way for exploring stable luminescent vinyl-linked COFs materials as promising fluorescent nanoprobes for targeted monitoring of antibiotic residues.