Rapid and Specific Aqueous-Phase Detection of Nitroaromatic Explosives with Inherent Porphyrin Recognition Sites in Metal–Organic Frameworks

Development of a rapid and effective method for the detection of 2,4,6-trinitrotoluene (TNT) in aqueous phase has attracted great attention. In this work, the fluorescent porphyrin-based metal–organic frameworks (MOFs) of PCN-224 were successfully exploited as a fluorescent probe for the rapid and selective TNT detection in water media. This strategy combined the advantages of fluorescent porphyrin molecules and porous MOFs, which not only overcame the aggregation of hydrophobic tetrakis(4-carboxyphenyl)porphyrin (TCPP) recognition sites but also promoted TNT to interact with recognition sites in virtue of the high surface and intrinsic open structure of MOFs. As a result, a rapid response time of as short as 30 s was obtained for the elaborated fluorescent probe. Meanwhile, the bright red emission of porphyrin units in PCN-224 could be proportionally quenched in correlation with the applied TNT level through the formation of TNT-TCPP complex in the ground state. The specificity of the employed sensory pl...