Facile synthesis of dual-ligand terbium-organic gels as ratiometric fluorescence probes for efficient mercury detection.

Mercury (Hg) pollution can negatively impact ecosystems, and there is a need for simple Hg monitoring platforms. Here, a dual-ligand fluorescence probe based on terbium-organic gels (Tb-LP MOGs) was constructed for efficient Hg detection. Tb-LP MOGs were developed through a facile room-temperature gelation method, showing two emission peaks derived from luminol and Tb at 424 nm and 544 nm, respectively. The aggregation-induced emission (AIE) effect between luminol and Tb led to luminol with blue fluorescence. However, Hg could dramatically quench the fluorescence signal of luminol at 424 nm because of the intense coordination interaction of Hg with luminol and photo-induced electron transfer (PET). The Phen ligand could sensitize the luminescence of Tb and offer a reference fluorescence, thus resulting in a unique ratiometric fluorescence response toward Hg. This novel nanoprobe had excellent linearity with Hg concentrations range of 0.1-30 μM; the detection limit was 3.6 nM. The analysis of real samples showed the potential application of MOGs for measuring Hg in porphyra and tap water. Mixed ligands were introduced for high-efficiency strategies to improve the analytical performance by regulating the emission behavior of MOGs.