Visual Detection of Hg2+ with High Selectivity Using Thymine Modified Gold Nanoparticles

Here, we describe a colorimetric sensor for detecting Hg2+ in aqueous media, which is simply constructed by the self-assembly of thymine acetamidoethanethiol (T-SH) on gold nanoparticles (AuNPs). Based on the specific interaction of Hg2+ with two thymines (T), the T-SH modified AuNPs can be induced to aggregate through the formation of a stable T-Hg-T complex in the presence of He2+, resulting in a color change from red to blue-gray. As low as 0.5 mu M of Hg2+ can be easily monitored by the naked eye using this sensor. Other metal ions, including Zn2+, Cd2+, pb(2+), Ni2+, cu(2+), co(2+), Mn2+, Ba2+, Fe2+, Ca2+, Mg2+, Al3+, and Fe3+, could not cause any response, even at concentrations 100-fold higher than Hg2+. The high selectivity, high stability and easy operation enable this sensor suitable for the rapid on-site detection of Hg2+ pollution.