Stable lanthanide sensor enables multicolor luminescence encoding and ratiometric detection for discriminating...

The widespread use of fluoroquinolone antibiotics (FQs) has necessitated the development of efficient on-site detection methods. Herein, a stable Zr-based MOF UiO-67-bpydc was post-synthetically modified with Eu³⁺ ions to create a red emissive probe Eu³⁺@UiO-67-bpydc. The antenna effect from the ligand to Eu³⁺ quenches the ligand emission, eliminating spectral overlap with FQs. Upon introducing FQs, the intrinsic fluorescence of FQs enhances while the characteristic red emission of Eu³⁺ at 616 nm is quenched, enabling a self-calibrating ratiometric sensing platform. This sensor achieves quantitative detection of six FQs with low limit of detection value (14.6 nM), rapid response, and high selectivity. Furthermore, a real-time colorimetric strategy was developed for the qualitative discrimination of different FQs. Recovery tests confirming the accuracy of the sensor and reliability in real water samples. This work provides a robust approach to designing an ideal optical sensor for the on-site analysis and visual identification of antibiotics in water.