A novel dual-ligand luminescent Eu-based metal-organic framework for ratiometric fluorescence sensing and visual detection of tetracycline.

Tetracycline (TC) residues in animal-derived food pose a significant threat to human health, necessitating the development of straightforward and user-friendly methods for TC detection to safeguard food safety. Here, a series of novel Eu-based metal-organic frameworks (Eu-MOFs) were prepared using a dual-ligand strategy. In the midst of these Eu-MOFs, Eu-ABPDC/BPDC exhibits the dual emission at 472 and 619 nm under single-wavelength excitation, enabling highly effective ratiometric fluorescence sensing of TC. Notably, the sensor presents favorable performance characteristics, including rapid response (90 s), high specificity, broad linear range (0.1-200 μM), and low detection limit (0.081 μM). Furthermore, based on the attractive performance of Eu-ABPDC/BPDC, it was further combined with carrageenan to prepare a hydrogel assay kit for onsite, smartphone-assisted visualization and quantitative detection of TC.