Highly sensitive gold nanoparticle-based colorimetric sensing of mercury(II) through simple ligand exchange reaction in aqueous Media

A strategy for the rational design of a novel colorimetric sensor based on dithioerythritol-modified gold nanoparticles for the selective recognition of Hg²+ in aqueous media is presented. This approach relies on the combination of gold nanoparticles with Hg²+ through sulfur-Hg ²+-sulfur interaction. The gold nanoparticles showed high selectivity toward Hg²+ with binding-induced red shift in the absorption spectra, with no response to major interfering cations such as Pb ²⁺,Cd²⁺, and Cu²⁺ in the presence of ethylenediamine tetraacetic acid. The system responds to Hg²+ with a detection limit of 100 nM and might open a new avenue for the development of Hg²+ sensing probes.