Gold nanoparticle-based colorimetric detection of mercury ion via coordination chemistry

A simple, fast, and convenient colorimetric detection of Hg2+ in aqueous media was presented based on the selective binding capability of thymine derivative (N-T) toward Hg2+. N-T decorated AuNPs solution was stable in red color, while the presence of Hg2+ induces significant aggregation of AuNPs along with red-to-blue color changes. Therefore, Hg2+ content in real water samples can be qualitatively detected by our naked eyes; meanwhile, good linear relationship of Hg2+ along with A650 nm/520 nm values could be obtained for its quantitative determination. Furthermore, our system shows excellent selectivity to mercury ions against any other tested metal ions and anions, and good sensitivity with LOD of 0.8 nM in real water samples.