A non-aggregation spectrometric determination for mercury ions based on gold nanoparticles and thiocyanuric acid.

We provide a highly sensitive and selective colorimetric assay to detect mercury ions (Hg 2+ ) in aqueous environment using thiocyanuric acid (TCA) molecule-functionalized gold nanoparticles (AuNPs). This method is based on the thiophilicity of Hg 2+ and AuNPs as well as the unique optical properties of TCA-functionalized AuNPs. In the presence of TCA, AuNPs aggregate due to the strong attraction between thiol groups of TCA and surface-bounded AuCl 4 - /AuCl 2 - ions, which induces the visible color change from red to blue. With the addition of Hg 2+ , Hg 2+ is more apt to interact with thiols than AuNPs. Thus, Hg 2+ can remove the AuNPs of the TCA-functionalized AuNPs and trigger AuNP aggregation redisperse again. This assay can selectively detect Hg 2+ with the detection limits as low as 0.5 nM in aqueous solution. [ABSTRACT FROM AUTHOR]