Highly sensitive and selective colorimetric detection of Hg2+ based on the separation of Hg2+ and formation of catalytic DNA–gold nanoparticles

Hg2+ ions can be absorbed onto a DNA–AuNP complex and separated from water samples while the catalytic activity of DNA–AuNPs can be promoted. Based on the above principle, a highly sensitive and selective colorimetric assay for the detection of Hg2+ was developed. The proposed method for Hg2+ has a detection limit of 1.5 nM with a linear range from 5.0 nM to 500 nM. Moreover, this detection method for Hg2+ demonstrated more than 1000-fold selectivity toward most of the possible interfering ions and can be used for tap water detection. The results indicate the high potential of AuNPs as an enzyme mimic for sensing heavy metal ions by metallophilic interactions.