Highly selective and rapid detection of pentachlorophenol in aqueous solution with metalloporphyrinic MOFs

Abstract Development of a rapid and effective strategy for the specific detection of hardly degradable pentachlorophenol (PCP) in aqueous phase is of great significance to human health and environmental security. Herein, a fluorescent metalloporphyrin-based metal-organic frameworks (MOFs) sensor of PCN-222(Zn) for PCP sensing was successfully developed, in which Zn-TCPP were simultaneously designed as organic ligands, fluorescent signal reporters and specific recognition sites. Thanks to their high surface area, open structure, exposed active recognition sites as well as excellent chemical stability, a trace amount of PCP in aqueous solutions could be rapidly detected within 30 s. Meanwhile, the fluorescence quenching of MOFs probe exhibited a linear correlation with the PCP level from 80 to 720 ppb and the limit of detection could reach to as low as 33 ppb. Additionally, the PCN-222(Zn) probe could specifically recognize PCP from other structurally similar analogues with a much higher Stern-Volmer quenching constant. The UV–vis and fluorescent lifetime decay spectra demonstrated that the specific recognition might benefit from the formation of a nonfluorecent Zn-TCPP-PCP complex through an axial coordination effect between central zinc atom in porphyrin ring and PCP molecule. The elaborated probe was successfully applied for the real quantitative detection of PCP in the mixed PCP analogues samples, prefiguring the great potentials of the PCN-222(Zn) MOFs probe in PCP pollutant detection.