A modified fluorescein derivative with improved water-solubility for turn-on fluorescent determination of Hg2+ in aqueous and living cells.

To improve the water-solubility of heavy-metal sensing materials, a modified fluorescein-based derivative, acryloyl fluorescein hydrazine (ACFH), was designed and developed by incorporating a non-hydrogen-bonding group into the conjugated molecule for weakening intermolecular hydrogen-bonding interactions. In neutral water environments, ACFH presented a fluorescence-enhancement performance at λ max =512 nm in the presence of Hg 2+ , which could be visualized by naked-eyes. Under the optimized conditions, the linear range of Hg 2+ detection was 1.0–100×10 −9 mol L −1 with a correlation coefficient of 0.9992 and a detection limit of 0.86×10 −9 mol L −1 . The recognition mechanism was confirmed to be a stable and irreversible 1:1 five-member ring complex between ACFH and Hg 2+ with a coordination constant of 3.36×10 9 . ACFH would possess a potential application in detecting Hg 2+ for biological assay with low cytotoxicity. [ABSTRACT FROM AUTHOR]