A selective, fluorescent probe for Hg2+ detection in aqueous solution

A novel fluorescent probe, 5-(2-benzothzaole)-2-thiophene boronic acid (1), for Hg2+ detection in aqueous solution was synthesized. (1) exhibited very strong fluorescence emission (ϕ = 0.92) in tris–HCl (pH 7.42) buffer aqueous solution. It was found that the fluorescence emission of (1) was quenched significantly upon addition of Hg2+ in buffer aqueous solution, whereas no marked fluorescence quenching was detected with addition of other metal ions (Ba2+, Ca2+, Cd2+, Co2+, Cu2+, Mg2+, Fe2+, Fe3+, Ni2+, Pb2+, Zn2+, Na+, K+) expect for Fe2+ and Fe3+, for which a small fluorescence quenching was detected in same condition. Competition experiment showed that no obvious interference was observed in its fluorescence while (1) performed the titration with Hg2+ in the different mixtures of metal ions.