β-cyclodextrin-functionalized silver nanoparticles for the naked eye detection of aromatic isomers.

We report herein the development of a highly robust, quantitative, sensitive, and naked eye colorimetric detection method for different isomers of aromatic compounds using β-CD-modified silver nanoparticle (AgNPs) probes. This assay relies on the distance-dependent optical properties of Ag nanoparticles and the different inclusion binding strength of the aromatic guests to β-CD host. In the presence of different isomers of aromatic compounds, AgNPs could be rapidly induced to aggregate, thereby resulting in apricot-to-red color change. The variety and concentration of different isomers of aromatic compounds could be determined by monitoring with the naked eye or a UV-vis spectrometer. The present detection limit for different isomers of aromatic compounds is 5 × 10(-5) M. We believe that the surface architectures of AgNPs after the introduction of the CD-based host-guest recognition would be applicable for a range of chemical and bioanalytical molecular sensing systems in aqueous media.