A highly selective colorimetric sensor for Hg2+ based on a copper (II) complex of thiosemicarbazone in aqueous solutions

By applying an indirect strategy, a new copper (II) complex of a thiosemicarbazone L has been successfully developed as a colorimetric chemosensor for the sensitive detection of mercury (II) ions. In the presence of copper (II) ions, the colorless solution of L became yellow; however, upon the addition of traces of mercury (II) ions, the yellow color faded to colorless immediately. Other ions, including Fe3+, Ag+, Ca2+, Zn2+, Pb2+, Cd2+, Ni2+, Co2+, Cr3+ and Mg2+ had a negligible influence on the probe behavior. The detection limits were 5.0x10(-6) M and 3.0x10(-7) M of Hg2+ using the visual color changes and UV-vis changes respectively. Test strips based on Cu-L were fabricated, which could act as a convenient and efficient Hg2+ test kits.