Abstract: A functionalized covalent organic framework probe, COF-TPA, was designed and synthesized for the specific recognition of HS-. The small-molecule triphenylamine derivative fluorescent probe was grafted onto a carboxyl-containing covalent organic framework (Tp-COOH COF) via EDC/NHS activation, yielding the novel probe COF-TPA. By virtue of the preorganized rigid aggregate structure of the COF framework and the extremely small ionic radius of HS-, the probe exhibited a marked fluorescence enhancement response toward HS? in pure water, thereby obviating the need for organic solvents and concentration adjustment that conventional AIE probes typically require. The probe was able to effectively eliminate interference from biothiols and other anions present in food matrices, featured a wide applicable pH range (5~13), and achieved a detection limit as low as 2.62?×?10-7?mol/L. The results demonstrate that the probe possesses a wide linear range, a low detection limit, and high sensitivity. Satisfactory accuracy and reliability were obtained for the determination of HS- in environmental water samples and alcoholic beverage matrices, indicating its promising potential for application in food safety detection.

Key words: Covalent organic framework, Fluorescent probe, H₂S