Fabrication of Dual-Ligand Zn-MOFs with Asynchronous Fluorescence Response for Efficient Ratiometric/Visual Sensing of Tetracycline Antibiotics in Animal-Derived Foods

The extensive use of tetracyclines in livestock poses health risks due to their residues in animal-derived food; therefore, developing simple detection methods to replace complex traditional approaches is of paramount importance. Here, we developed a dual-ligand zinc-based metal–organic framework material, Zn-BTC-BDC-NH2 (denoted as ZTD), for the detection of tetracyclines. The intrinsic blue fluorescence of ZTD was quenched upon the introduction of tetracyclines due to electron transfer from −NH2 of ZTD to −CO– and −OH groups of tetracycline molecules; meanwhile, the new green fluorescence emission was generated through π–π stacking between aromatic rings and the formation of complexes between Zn2+ and C–O/C═O groups. In real food samples, ZTD exhibited recovery rates ranging from 93.62 to 110.66%, with detection limits as low as 0.011 μmol·L–1. Additionally, a ZTD fluorescence test paper was developed for portable detection. This study presents a novel tetracycline detection method, offering insights into multiligand metal–organic framework preparation and future sensing method design.