A turn-on reactive fluorescent probe for Hg²⁺ in 100% aqueous solution

It is an effective and precise strategy to design the fluorescence probe for Hg²⁺ based on a new specific reaction. A novel turn-on fluorescent probe, 4-{2-[4-(2-Mercapto-benzoyloxy)-phenyl]-vinyl}-1-methyl-pyridinium[e]iodide (MBPVP) for Hg²⁺ was developed. The mechanism was based on Hg²⁺-mediated ester hydrolysis to release the fluorophore, 4-[2-(4-Hydroxy-phenyl)-vinyl]-1-methyl-pyridinium[e]iodide, which showed outstanding intramolecular charge transfer (ICT) and the yellow-green fluorescence were observed. The turn-on probe showed rapid response time, outstanding selectivity and sensitivity for Hg²⁺ over other metal ions in 100% PBS buffer (pH = 7.4). The linear range was 2-16 µM and the detection limit was 6.5 nM. Furthermore, MBPVP was used to determine Hg²⁺ in real samples and in the solid state.