Ultrasensitive, rapid and selective sensing of hazardous fluoride ion in aqueous solution using a zirconium porphyrinic luminescent metal-organic framework.

The development of a rapid and sensitive method for the detection of fluoride ion (F) in aqueous systems is of great significance for human health and environmental monitoring. In this study, a zirconium porphyrinic luminescent metal-organic framework (LMOF), PCN-222, was employed as a novel fluorescent probe for the ultrasensitive, rapid and selective detection of F in water. The PCN-222 probe was prepared by a facile solvothermal method. It exhibited good fluorescence stability and was highly stable in water. The fluorescence emission of PCN-222 could be effectively and selectively quenched by F due to the strong coordination affinity of F to the zirconium clusters in PCN-222. The proposed fluorescence method for F detection based on PCN-222 probe afforded a linear response range of 1-20 μmol/L and a very low detection limit (0.048-0.065 μmol/L) in reference to many reported F fluorescent probes. Moreover, a rapid response time (<10 s) was obtained due to the open and uniform pore structure of PCN-222 that allowed the fast diffusion of F to interact with the zirconium recognition sites. Finally, the PCN-222 probe was successfully applied for the fluorescence detection of F in real water samples. These results highlight the great application potential of LMOF in the sensing fields.