Vinyl substituted triphenylamine based turn-off fluorescent probe for selective and sensitive detection of mercury (II) in water and live cells.

[Display omitted] • TPA-alk is a simple, fluorescent, and biocompatible probe which could synthesized in couple of steps using triphenylamine. • The sensing of Hg2+ using TPA-alk is via oxymercuration-demercuration. • TPA-alk displayed high selectivity, distinctive fluorescence quenching, and spectral changes against mercury (II) ions over fifteen different competitive metal ions. • TPA-alk could penetrate through the cell membrane and is capable of detecting Hg2+ in a biological environment at the micromolar level. Here, we report vinyl substituted triphenylamine (TPA-alk) fluorescent probe for the rapid and efficient detection of mercury ion (Hg2+) in water and biological environment. TPA-alk detects Hg2+ selectively over a wide range of competitive metal ions with a blue shift of 43 nm in the UV absorbance spectrum. The detection limit is found to be 0.146 µM (29.2 ppb) with high selectivity over a wide range of competitive metal ions. DFT study explains the blue shift in the UV–vis absorption band of the optical probe upon the addition of Hg2+. Cell viability assay illustrates that the probe is biocompatible and it has low cytotoxicity even at its higher concentration. Cell imaging studies demonstrate the efficiency of the TPA-alk probe for the micromolar detection of mercury (II) in live BMG1 cells. [ABSTRACT FROM AUTHOR]