A new fluorescent probe based on quinoline for detection of Al3+ and Fe3+ with “off–on–off” response in aqueous solution

Abstract

A new quinoline-based fluorescent probe 1 has been designed and synthesized. Fluorescence emission spectra of the probe showed red-shift and obvious enhancement of fluorescent intensity upon the addition of Al³⁺ (turn-on). 1–Al³⁺ showed high selectivity for Fe³⁺ over other metal ions, and eliminated the interference of Al³⁺ during Fe³⁺ detection (turn-off). It showed highly selective relay recognition of Al³⁺ and Fe³⁺ via a fluorescence “off–on–off” mechanism. Fluorescence spectra indicated that the response of 1–Al³⁺ to Fe³⁺ was caused by central metal displacement. The detection limits for the analysis of Al³⁺ and 1–Al³⁺–Fe³⁺ ions were calculated to be 2.20 × 10⁻⁶ M and 1.96 × 10⁻⁵ M, respectively. Living HeLa cell imaging studies revealed that the probe was cell-permeable and it could be used to detect intracellular Al³⁺ and Fe³⁺ ions.