Heterometallic Eu/Cd-MOF Dual-Channel Fluorescent Sensor Array for Hierarchical Antibiotic Discrimination: From Cross-Class to Intra-Class Resolution

Herein, we report a hierarchical molecular recognition platform based on a single mixed-ligand Eu/Cd heterometallic metal–organic framework (MOF) featuring atomically homogeneous emissive centers. Precise Eu³⁺ substitution at Cd²⁺ nodes yields two spectrally distinct emission channels at 450 nm (ligand-centered) and 612 nm (Eu³⁺-centered), which generate characteristic fluorescence fingerprints through analyte-specific differential modulation.

Configured as a dual-channel sensor array, this single-MOF platform achieves 100% accurate classification of four antibiotic classes (fluoroquinolones, tetracyclines, sulfonamides, and aminoglycosides) and precisely resolves structurally analogous fluoroquinolones (ciprofloxacin, enrofloxacin, norfloxacin) differing by <10% in molecular weight. Machine learning integration further enables concentration-independent discrimination of three fluoroquinolones, effectively mitigating concentration-induced signal variations and enabling robust identification of blind samples.