Characterization of a highly Cu2+-selective fluorescent probe derived from rhodamine B

Abstract A rhodamine B derivative was synthesized and characterized as a highly selective and sensitive probe for Cu 2+ in ethanol–water solution (2:3, v:v, pH7.4, 50 mM HEPES). A prominent fluorescence enhancement at 575 nm was observed in the presence of Cu 2+ , accompanied by the change in the absorption spectrum. Under the optimal conditions, a good linear range of 0.5–1.5 μM with a detection limit of 1.6 × 10 −7  M were obtained. Furthermore, confocal laser scanning microscopy experiments have proven that this probe is cell-permeable and can respond to changes in intracellular Cu 2+ in living cells.