A novel strategy to construct MOFs-based probes using new reactive coumarin ligands for rapid and sensitive detection of hydrogen sulfide (H2S)

To further enhance the performance of MOFs-based hydrogen sulfide (H₂S) detection probes, we proposed a novel strategy for constructing for H₂S detection. We have designed and synthesized a new reactive coumarin-based ligand (NTA) and directly prepared the MOFs-based fluorescent probe UiO-66-NTA using the new ligand. This approach overcame the issues of low grafting rates and uneven reactive sites associated with post synthetic modification (PSM) strategy prepared MOFs-based fluorescent probes. This construction strategy endowed MOFs with a greater number of active sites on their surfaces for H₂S detection, thereby achieving superior sensing performance for H₂S, which included an ultra-fast response time (5 s) and a low detection limit (0.063 μM). The rigid topological structure of the MOFs minimizes π-π interactions between fluorophores, conferring aggregation-induced emission (AIE) characteristics to the probe. To enhance the practical utility of the probe, a smartphone-assisted test strip sensing system was developed and successfully applied to the detection of real water samples. Additionally, the probe was integrated into the sodium alginate (SA) hydrogel to create a portable sensor UiO-66-NTA@SA for assessing the freshness of meat by detecting H₂S.