Highly Selective Fluorescence Detection for Mercury (II) Ions in Aqueous Solution Using Water Soluble Conjugated Polyelectrolytes

A highly selective assay method has been developed to detect mercury (II) (Hg²⁺) ions using cationic conjugated polymer (CCP). The transduction mechanism is based on a Hg²⁺ promoted reaction. In the absence of Hg²⁺ ions, the CCP can form the complex with an anionic 1,3‐dithiole‐2‐thione derivative through electrostatic interactions. The fluorescence of CCP is efficiently quenched by 1,3‐dithiole‐2‐thione derivative via an electron transfer process. Upon adding Hg²⁺ ions, the transformation of 1,3‐dithiole‐2‐thione into 1,3‐dithiole‐2‐one inhibits the quenching, and the fluorescence of CCP is recovered. Distinguishing aspects of this assay include the signal amplification of CCPs and a specific Hg²⁺ promoted reaction. By triggering the change in the emission intensity of CCP, it is possible to detect Hg²⁺ ions in aqueous solution.