Highly selective and effective mercury(II) fluorescent sensors

A novel mercury non-sulfur and simple fluorescent chemosensor L based on the benzimidazole group and quinoline group as the fluorescence signal group has been designed and synthesized. The receptor could instantly detect the Hg2+ cation over other cations such as Fe3+, Ag+, Ca2+, Cu2+, Co2+, Ni2+, Cd2+, Pb2+, Zn2+, Cr3+, and Mg2+ by fluorescence spectroscopy changes in H2O/DMSO (1 : 9, v/v) solution with specific selectivity and high sensitivity. The fluorescence color of the solution containing sensor L showed a remarkable change from blue to colorless only after the addition of Hg2+ in aqueous media while other cations did not cause obvious color changes. Moreover, further study demonstrates that the detection limit on the fluorescence response of the sensor to Hg2+ is down to 9.56 x 10(-9) M, which is far lower than the maximum level for mercury of 0.01 M in drinking water, from EPA guidelines. Test strips based on L were fabricated, which could act as convenient and efficient Hg2+ test kits. Thus, the probe should have potential applications in an aqueous environment for the monitoring of mercury.