Dual-lanthanide functionalized hydrogen-bonded organic frameworks for fluorescent detection of quinolone antibiotics...

To address the urgent need for antibiotic detection, rapid and reliable sensors are imperative. In this study, a novel dual-lanthanide-ion-modified hydrogen-bonded organic frameworks (HOFs) was developed as a fluorescence sensor, named EuTb@ME-IPA, for norfloxacin (NOR) and ciprofloxacin (CIP) detection. The dual lanthanide ions (Eu^3 + and Tb³⁺) were anchored through the coordination with carboxyl and amino groups in the HOFs. The energy transfer from the HOFs to Eu³⁺ and Tb³⁺ endowed the material with dual-emission characteristics. Notably, EuTb@ME-IPA overcame the limitation of traditional materials restricted to single-medium detection, enabling the detection in multi-media: i) ratiometric fluorescence detection in ethanol; ii) fluorescence "turn-on" response in aqueous media; iii) ratiometric fluorescence detection via fluorescent films. All the three detections exhibited rapid response in seconds, high sensitivity with the limits of detection (LODs) as low as 0.048 μM (NOR) and 0.037 μM (CIP), and excellent selectivity. Furthermore, the EuTb@ME-IPA based fluorescent film enabled visual detection in real water samples. In addition, the coordination of carboxyl groups in NOR/CIP with Tb³⁺ induces an "antenna" effect, which was mechanistically certified through DFT calculations and spectral characterization. This study provides new insights for developing portable antibiotic sensors and advancing fluorescence-based strategies for water quality monitoring. ENVIRONMENTAL IMPLICATION: Ciprofloxacin (CIP) and norfloxacin (NOR), classified as quinolone antibiotics, are emerging environmental contaminants of concern in water. Their low biodegradability leads to persistent accumulation in surface water, which disrupts microbial community homeostasis, induces antibiotic resistance gene dissemination, and threatens human health via food chain bioaccumulation, manifesting as hepatorenal toxicity, intestinal microbiota dysbiosis and neurotoxicity. To assess their environmental risks, a simple radiometric fluorescent sensor of EuTb@ME-IPA was developed to achieve highly sensitive and selective detection in multiple media. It provides technical support for monitoring of quinolone contamination in environmental matrices, thereby supporting ecosystem conservation.