Detection of Hg2+ based on the selective inhibition of peroxidase mimetic activity of BSA-Au clusters

It was found that Hg2+ can inhibit the peroxidase mimetic activity of bovine serum albumin (BSA) protected Au clusters (BSA-Au) due to the specific interaction between Hg2+ and Au+ existed onto the surface of BSA-Au clusters. By coupling with 3, 3′, 5, 5′-tetramethylbenzidine (TMB)–H2O2 chromogenic reaction, a novel method for Hg2+ detection was developed based on the inhibiting effect of Hg2+ on BSA-Au clusters peroxidase-like activity. This method exhibited high selectivity and sensitivity. As low as 3 nM (0.6 ppb, 3σ) Hg2+ could be detected with a linear range from 10 nM (2 ppb) to 10 µM (2 ppm) and this method was successfully applied for the determination of total mercury content in skin lightening products.