A reversible rhodamine 6G-based fluorescence turn-on probe for Fe3+ in water and its application in living cell imaging

Abstract

A reversible fluorescent probe L based on rhodamine 6G is synthesized for the optical detection of Fe³⁺ in water. This probe displays favorable selectivity for Fe³⁺ with a 1 : 1 stoichiometry. It displays a fluorescence turn-on response in the process of rhodamine ring opening with Fe³⁺ and a fluorescence turn-off response with the addition of Na₄P₂O₇ to the L-Fe³⁺ complex. The association constant between the probe and Fe³⁺ was detected to be 3.5 × 10⁴ M⁻¹, and the corresponding detection limit was calculated to be 1.9 × 10⁻⁸ M according to fluorescence titration analysis. Furthermore, bioimaging investigations indicated that this probe was cell permeable and suitable for monitoring intracellular Fe³⁺ in living cells by confocal microscopy.