A simple ‘turn-on’ fluorescence chemosensor for Al(iii) detection in aqueous solution and solid matrix

Abstract

A simple fluorescence chemosensor of FHS-OH based on salicylaldehyde Schiff base was developed via a one-step reaction, which achieved a fast and highly selective response for Al(III). Mechanism studies showed that when FHS-OH was exposed to Al(III) with 1 : 2 binding stoichiometry in an aqueous solution at neutral pH, CN isomerization and PET processes were limited, resulting in a ‘turn-on’ fluorescence response with a low detection limit of 63 nmol L⁻¹ and a satisfying linear range of 0.0–20.0 μmol L⁻¹. Compared to traditional detection methods for Al(III), fluorometry using FHS-OH has several advantages, including simplicity, quick response, and capability of real-time detection. More importantly, the detection of Al(III) on a solid matrix (test paper) was successfully achieved. After the addition of Al(III), a significant emission colour change from green to bright blue was observed by the naked eye owing to the intrinsic aggregation-induced emission (AIE) characteristic of FHS-OH.