A highly sensitive and selective Zn-based luminescent MOF for specific detection of trinitrotoluene in aqueous phase

Abstract

The existence of nitroaromatic compounds, specifically 2,4,6-trinitrotoluene (TNT), in water reservoirs poses significant health risks, necessitating robust detection and monitoring strategies. In this study, we leverage the exceptional properties of the previously synthesized metal-organic framework (MOF), PUC2 as a highly luminescent probe for selective and sensitive detection of TNT in aqueous media. PUC2 exhibits remarkable luminescence, emitting a vivid blue light, making it an ideal candidate for TNT detection. Our investigations reveal that PUC2 demonstrates outstanding sensitivity, achieving an impressive detection limit of 0.145 μM towards TNT which can be attributed to the robust probe-analyte interactions evident from the quenching constant (Ksv) value of 0.18 × 104M−1. An intriguing aspect of PUC2 is its adaptability to a wide pH range, maintaining its sensing capabilities effectively in aqueous phase with pH levels ranging from 4 to 11. The predominant quenching mechanism in this context appears to be photoinduced electron transfer (PET), with an additional enhancement through Forster resonance energy transfer (FRET). The unique combination of structural features and exceptional sensing capabilities of PUC2 opens up new avenues for environmental monitoring and security applications, highlighting its potential as a highly effective luminescent sensor for detecting hazardous substances like TNT.