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

It was found that Hg 2+ can inhibit the peroxidase mimetic activity of bovine serum albumin (BSA) protected Au clusters (BSA-Au) due to the specific interaction between Hg 2+ and Au + existed onto the surface of BSA-Au clusters. By coupling with 3, 3′, 5, 5′-tetramethylbenzidine (TMB)–H 2 O 2 chromogenic reaction, a novel method for Hg 2+ detection was developed based on the inhibiting effect of Hg 2+ on BSA-Au clusters peroxidase-like activity. This method exhibited high selectivity and sensitivity. As low as 3   nM (0.6   ppb, 3 σ ) Hg 2+ 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.