Hydrogen-bond enhanced Tb/Eu-MOF for visual detection of multiple trace fluoroquinolones in seawater and a portable 3D-printed sensor

To address the urgent need for rapid and on-site detection of trace antibiotic contamination in marine environments, this study employs a hydrogen-bond network enhancement strategy to construct a highly salt-resistant dual-lanthanide MOF, Tb/Eu-BTC@BTEC, for the sensitive and visual sensing of three fluoroquinolone antibiotics. By introducing the carboxyl-rich ligand H₄BTEC to cooperate with H₃BTC, a unique "double-crown" three-dimensional structure was formed to significantly reinforce intermolecular hydrogen-bonding networks and π-π stacking interactions. This structural design effectively resists interference from high-salt ions in seawater, resulting in only 1.97% fluorescence decay within 30 min in simulated seawater. The ratiometric fluorescence sensor responds instantaneously even in complex seawater matrices and achieves nanomolar-level detection limits (LODFLE = 80.7 nM, LODNOR = 21.03 nM, and LODENR = 28.22 nM) within the 0-10 µM target range. Furthermore, a portable detection platform was developed by 3D printing that enables visual, quantitative antibiotic monitoring via RGB-CIE colorimetric analysis. Spike recovery tests in real seawater samples (coastal and aquaculture areas) yielded recoveries of 93-110% with relative standard deviations below 6%. The result provides novel insights for developing stable sensors suitable for high-salt systems and pioneer new approaches for rapid on-site screening of pollution in marine environments.