Electrostatic Effect-Induced Eu/UiO-66 MOF Regulation for Rapid and Selective Recognition of PFOA

The detection of per- and polyfluoroalkyl substances (PFASs) in the environment is critical due to their adverse health effects, but it remains challenging because of the high cost and technical complexity of standard analytical methods. We developed a series of rare earth-based bimetallic metal-organic frameworks (MOFs) for the sensitive and efficient fluorescence detection of perfluorooctanoic acid (PFOA). By systematically modulating the ligand functional groups with amino (-NH₂), hydroxyl (-OH), and fluorine (-F) moieties, the influence of ligand electronegativity on the PFOA recognition performance was evaluated. The experimental results demonstrated that the local electrostatic potential of the MOFs, governed by the functional groups, is a critical factor in determining the PFOA binding affinity and fluorescence sensitivity. Eu/UiO-66-NH₂ demonstrated the highest sensitivity and selectivity for rapid fluorescence detection of PFOA, which was due to its strong positive electrostatic potential to facilitate binding via electrostatic attraction and synergistic hydrogen bonding. PFOA concentrations in actual water samples can also be determined by Eu/UiO-66-NH₂. These findings provide theoretical insights and experimental support for the functional design of MOF-based sensors, paving the way for the sensitive and selective detection of PFASs.