BSA-stabilized Au clusters as peroxidase mimetic for colorimetric detection of Ag+

Rapid and sensitive detection of Ag + in aquatic ecosystems is of great significance for public health and environmental security. In this report, a simple and feasible colorimetric method for the detection of Ag + at an ultralow concentration is developed. Bovine serum albumin stabilized gold nanoclusters (BSA@AuNCs) possess the peroxidase-like activity that could catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H 2 O 2 . Once Ag + is introduced, Ag + selectively reacts with Au° through redox reaction, which induces an apparent inhibition of the peroxidase-like activity of BSA@AuNCs. On the basis of this effect, a colorimetric Ag + sensor is established. The high specificity of the Ag–Au interaction provides excellent selectivity over the interfering metal ions. The lowest detectable concentration for Ag + is 0.204   μM. And this method could be applied for the rapid analysis of Ag + in lake water with satisfactory results. These advantages demonstrate that the proposed method is a promising candidate for the detection of Ag + in water samples.