Promising optical chemical sensor for detecting Al(III) ions in water based on organic fluorophore

Abstract

In the present work, an optical sensing scheme was designed to detect the Al(III) ions based on a fluorescent probe. The synthesized probe N-(3-chloro)-salicylaldimine CSI receptor was developed using turn-on fluorescence enhancement. During the treatment process of Al(III) ions, the emission of the CSI probe was increased at 545 nm due to the formation of a 1:1 complex between the chemosensor and the Al(III) ions at room temperature. The gradual addition of Al(III) ions to the studied solution gradually enhanced the CSI emission. The other metal ions, including alkali, alkaline metal ions, and some transition metal ions, had no noticeable impact on the fluorescent intensity. The limit of detection (LOD) and (LOQ) were determined as 0.427 nM and 1.28 nM, respectively. The detection limit for this sensor is very low, demonstrating its remarkable selectivity and ultra-sensitivity. These impressive characteristics allow the detection of Al(III) ions at concentrations as low as 1.28 × 10⁻³ to 1 μM while highly selective even in the presence of other metal ions. EDTA solution at a concentration of 1 µM was used to make the sensor reversible. We also provide the fact that the CSI probe can be a promising optical chemical for detecting Al(III) ions in real samples.