Lanthanide-Functionalized Metal-Organic Framework as Ratiometric Probe for Selective Detection of 4-NA and Fe3+

Luminescent MOFs with dual or multiple emission centers can act as multi-target and self-calibrating probes to selectively detect environment pollutants with high precision. In this paper, we synthesized Ln(3+)@Zn-MOF (Ln(3+) = Eu3+ and Tb3+) with dual emission characteristics by post-encapsulation Ln(3+) ions into Zn-MOF. The fluorescence sensing experiments show that Eu3+@Zn-MOF can be used as a multi-functional and self-calibrating probe to selectively detect 4-nitroaniline (4-NA) and Fe3+ ions with high sensitivity, good anti-interference and repeatability. The LOD is 6.01 mu M and 60.99 mu M for 4-NA and Fe3+ ions, respectively. Compared to the pristine Zn-MOF, Eu3+@Zn-MOF exhibits the higher sensitivity and accuracy in detection application. Further studies on UV-vis adsorption spectra show that the possible fluorescence quenching mechanism are the competitive absorption of excitation light between MOF and the analytes. And this work presents a promising strategy to prepare dual emissions probes for effective detection of environment pollutants.