Highly sensitive ratiometric fluorescence detection of tetracycline residues in food samples based on Eu/Zr-MOF

The development of a simple, rapid, and sensitive method for monitoring antibiotic residues is crucial for maintaining food safety. Herein, a ratiometric fluorescence probe based on bimetallic organic framework (Eu/Zr-MOF) was developed for the detection of tetracycline (TC). The Eu/Zr-MOF was synthesized by the coordination of Eu³⁺ and Zr⁴⁺ with 2-APDC, which exhibited a grape-like cluster morphology and dual-emitting fluorescence at 430 nm/616 nm. Based on the internal filtering effect (IFE), significant fluorescence quenching was observed at 430 nm, whereas only slight changes occurred at 616 nm. The ratiometric sensing offered two broad linear ranges (0.5-8 μg/mL; 10-60 μg/mL) and a low detection limit (26.7 ng/mL). The proposed method was applied to the determination of TC in pork and water samples. Fluorescent sensors have the advantages of simple design, fast response, and high sensitivity, thus providing a promising means for evaluating the safety of food contaminated with TC.