A luminous strategy for the recognition of toxic antibiotics in water via efficient energy transfer

Fluoroquinolones (FQs) are the class of Antibiotics (ABs) that have been extensively used worldwide for the treatment of diseases caused by bacterial infections. In India, most of these untreated ABs and their unused metabolites present in treated and untreated wastewater end up in agricultural land and water bodies. This can accelerate the problem of antimicrobial resistance in the community. Hence, we aim to develop a cost-effective sensor to detect and monitor the presence of such drugs in water bodies. We have prepared a chemically reduced graphene oxide (rGO) integrated luminescent cerium metal-organic framework (MOF) that specifically targets and recognizes ciprofloxacin (CPFX), norfloxacin (NFX), and ofloxacin (OFX) achieving excellent sensing activity. A remarkable quenching of the fluorescence of MOF composite was observed upon interaction with CPFX, NFX, and OFX with 57.9, 46.3, and 51.6 ppb as limits of detection, respectively, through a Forster resonance energy transfer from the Ce-MOF to the analytes. The applicability of the sensor was also examined with real-time samples collected from the rivers of Chennai city and the MOF probe exhibited an appreciable recovery of results. This is the first study on Ce-MOF-based rGO composite providing a solid rationale for fluorescence detection of FQs with exceptional quenching efficiency and very high sensitivity for monitoring FQs in water bodies even in diluted conditions.