A highly selective and sensitive fluorescent chemosensor for detecting Al ³⁺ ion in aqueous solution and plant systems

The solubilized form of aluminum, Al ³⁺ , is present under acid soil conditions and toxic to both animals and plants. Detecting and quantifying Al ³⁺ is vital for both chemistry and biology. A new Schiff-based fluorescent turn-on sensor (probe L) for the selective detection of the Al ³⁺ ion was synthesized by coupling 2-hydroxy-1-naphthaldehyde and 2-aminoisoindoline-1,3-dione, and the structure was characterized by nuclear magnetic resonance spectra. The probe L exhibited an excellent selective and sensitive response to the Al ³⁺ ion over other metal ions in DMSO-H2O (1: 9 v/v). Fluorescence quantification revealed that probe L was promising for the detection and accumulation of Al ³⁺ . Treating rice seedlings with Al ³⁺ at 25-200 µM inhibited their growth. Al ³⁺ treatment produced reactive oxygen species in rice roots. Practical applications of the fluorescent probe for the quantification of Al ³⁺ in water samples and rice seedlings are demonstrated. Detecting the Al ³⁺ ion with the probe L is easy and a potential alternative to existing analytical methods. The method can be used for detecting the Al ³⁺ content of aqueous solution and plant systems. The novel fluorescent probe L has good potential for monitoring Al ³⁺ content in the environment and biological systems.