A highly sensitive chemosensor for rapid recognition of Cu2+ and HSO3- in 100% aqueous solution.

Abstract Dual-responsive chemosensors have garnered much research interests owing to the ability of recognizing two analytes simultaneously. Herein, the chemosensor BPIS composed of hemicyanine and 2, 2′-dipyridylamine (DPA) was facilely synthesized for sensitive and expeditious recognition of Cu2+ and HSO3− in 100% aqueous solution. By adding Cu2+, BPIS showed substantial spectral changes accompanied by a noticeable color change from pink to yellow under daylight. The absorbance and fluorescence intensity were linearly correlated to the Cu2+ concentration, enabling the quantitative recognition of Cu2+. The limit of detection (LOD) for Cu2+ was down to 4.02 × 10−9 M. The response time of BPIS towards Cu2+ was 10 s, imparting BPIS great potential in real-time detection of Cu2+. Meanwhile, BPIS manifested ratiometric fluorescence response by introducing HSO3− owing to the 1,4-addition between HSO3− and the unsaturated C C bond of BPIS. The color of the BPIS solution progressively faded from pink to colorless with increasing HSO3− concentration, and a LOD of 3.47 × 10−9 M was obtained. In addition, BPIS-coated test paper was found to be an efficient tool for fast, sensitive, portable detection of Cu2+ and HSO3− by naked eyes. More importantly, the precise detection of Cu2+ and HSO3− in real water and sugars were realized, respectively, by capitalizing on BPIS as the signal tool.