Chloroauric Acid/Silver Nanoparticle Colorimetric Sensors for Antioxidant Discrimination Based on a Honeycomb Ag-Au Nanostructure
Xin Zhang, Zhengbo Chen, Xia Zuo
Abstract
We propose an effective visual sensor array for the determination and differentiation of antioxidants. The sensing system includes three diverse concentrations of chloroauric acid (HAuCl4) as receptors and silver nanospheres (AgNPs) as colorimetric probes. In the assay, Au3+ was reduced into Au atoms and deposited on surfaces of AgNPs. Meanwhile, the AgNPs were oxidized to Ag+ by HAuCl4 and separated from the AgNPs. However, in the presence of different antioxidants, HAuCl4 was reduced by different degrees, causing varying degrees of AgNP etching and gold deposition, which would result in distinctive colorimetric signal patterns for pattern differentiation of target antioxidants via linear discriminant analysis (LDA). The above results indicated that at least three HAuCl4/AgNP sensors can successfully recognize five kinds of antioxidants at the 10 nM level. In addition, selective experiments and practical application tests have shown that the sensing strategy has outstanding anti-interference ability and excellent application in human serum.