Colorimetric and fluorescent probe based on coumarin for sequential sensing of mercury (II) and cyanide ions in aqueous solutions

Abstract

A novel coumarin-thiol chemosensor L for sequential colorimetric and fluorescent detection of mercury (II) and cyanide ions in aqueous solution has been designed and prepared. The probe L exhibits high selectivity and sensitivity towards mercury (II) cations, and forms the complex L/Hg2+ which exhibits red-shift and fluorescence quenching. In turn, the complex L/Hg2+ shows high selectivity for cyanide anions, which release the L probe and explain the blue shift and restoration of the original fluorescence. A test paper was also developed by fixing the probe L on the surface of a filter paper. This test paper allows the simultaneous detection of mercury (II) and cyanide ions in pure water without the need for additional equipment.