A dual-emission tb-MOF-based Ratiometric fluorescent probe for multiplexed detection and discrimination of...

The development of sensitive and selective sensing platforms for monitoring antibiotic residues is crucial for environmental protection and public health. Herein, a highly luminescent terbium-based metal-organic framework (Tb-MOF) was synthesized using a dual-ligand strategy with 1,4-benzenedicarboxylic acid (H₂bdc) and 1, 2, 4-benzenetricarboxylic acid (H₃btc). By encapsulating Rhodamine B (RhB) into its pores, a novel ratiometric fluorescent probe, RhB@Tb-MOF, was fabricated. This probe demonstrates selective and sensitive turn-on fluorescence response toward norfloxacin (NOR) and turn-off responses toward tetracycline (TC) and nitrofurazone (NFZ), achieving notably low detection limits of 9 nM, 0.055 μM, and 0.125 μM, respectively. The underlying mechanisms for fluorescence enhancement and quenching were systematically elucidated, involving synergistic effects of the Antenna Effect, competitive absorption, photoinduced electron transfer, and intermolecular interactions. Furthermore, to address the challenge of discriminating these antibiotics in mixtures, a sensor array coupled with linear discriminant analysis (LDA) was developed, enabling high-precision classification of single, binary, and ternary antibiotic solutions. For practical application, a smartphone-enabled portable device was built for visual on-site quantitative detection. This work provides a reliable method for constructing high-performance fluorescent sensors in environmental monitoring.