Analytical Sciences

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

Xiangjun LIU, Xiaohong CHENG, Tao BING, Canliang FANG, and Dihua SHANGGUAN

Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China

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 Hg²⁺, resulting in a color change from red to blue-gray. As low as 0.5 μM of Hg²⁺ can be easily monitored by the naked eye using this sensor. Other metal ions, including Zn²⁺, Cd²⁺, Pb²⁺, Ni²⁺, Cu²⁺, Co²⁺, 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.

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