A Dansyl-Rhodamine Based Fluorescent Probe for Detection of Hg2+ and Cu2+

Abstract

A novel fluorescent probe based on dansyl-appended rhodamine B was developed. The probe can selectively recognize and sense Hg²⁺ and Cu²⁺ from other common metal ions by showing unique fluorescence and absorption characteristics. In MeCN/HEPES buffer solution, the probe gives a ratiometric fluorescent response to Hg²⁺, which was ascribed to the fluorescence resonance energy transfer from dansyl moiety to the ring-opened rhodamine B moiety, while the presence of Cu²⁺ causes fluorescence quenching. Beside the fluorescence change, the presence of Cu²⁺ and Hg²⁺ can induce intensive absorption at about 555 nm, which resulted in a color change from colorless to pink.