Dual recognition of Zn2+ and Al3+ ions by a novel probe containing two fluorophore through different signaling mechanisms

Abstract

A new reactive and highly selective fluorescent sensor (CBA) containing 4-cyanobiphenyl and anthracene as two fluorophores was synthesized for the detection of Zn2+ and Al3+ ions. CBA exhibited an effectively selective and sensitive recognition towards Zn2+ and Al3+ ions through two different mechanisms (i.e. PET, C = N isomerization and hydrolysis) in EtOH-H2O (v/v = 95/5) over other cations. The complexation properties of CBA with Zn2+ and Al3+ ions were examined by UV–vis, 1H NMR and FTIR experiments. This sensor showed high sensitivity for Zn2+ and Al3+ with detection limits (LOD) as low as 78.8 and 52.2 nM, respectively, and high selectivity through a ‘turn-on’ fluorescence response over the other tested metal ions. To check its applicability, an easy prepared test paper strip of CBA was produced for rapid and selective detection of Zn2+ and Al3+ ions. Also, the determination of Zn2+ and Al3+ in water samples was evaluated.