A Sensitive Fluorescent Turn-on Probe NapP-deap Based on Naphthalimide Derivative to Detect Hg(II) Ions in HEPES Buffer Solution and Living Cells

A highly sensitive fluorescent “turn-on” probe NapP-deap based on naphthalimide derivative was developed that bound Hg 2+ ions rapidly in the N -2-hydroxyethylpiperazine- N -ethane-sulphonic acid(HEPES) buffer solution via photo-induced electron transfer(PET) being inhibited mechanism. The titration experiment displayed that the emission intensity of NapP-deap at 540 nm was almost linearly increased by about 3-fold. The Job’s plot showed a stoichiometry factor of 1:1 of the ligand-to-metal ratio. The detection limit of fluorescent probe was calculated to be 6.2×10 −9 mol/L. 1 H NMR studies could confirm that one Hg 2+ ion was bound by the N atoms(a, b) of piperazine or the N atom(c) of pyridine. The fluorescent probe could be used for the detection of Hg 2+ ions in living cells.