Highly Selective Fluorescent Sensor for Detection of Al³⁺ Based on Schiff-Base of 2-Hydroxy-1-Naphthaldehyde and 8-Aminoquinoline and Its Applications

Aluminum is a widely distributed element and plays an indispensable role in our lives, but excessive intake of Al³⁺ can cause potential harm to human health. Highly selective methods for the rapid detection of Al³⁺ are urgently needed. Here, a novel "turn on" fluorescent probe L based on Schiff-base of 2-hydroxy-1-naphthaldehyde and 8-aminoquinoline was obtained in an excellent yield. Probe L presents significant properties such as rapid response, good stability, wide pH range, simple synthetic operation, and provides an efficient strategy for the highly selective detection of Al³⁺ in an aqueous solution of DMSO/H₂O (7:3, v:v). According to Job's curve and fluorescence titration, probe L with Al³⁺ forms a 2:1 ratio of complex, and the lowest limit of detection is 3.23 × 10⁻⁸ mol/L. The possible combination mode for probe L with Al³⁺ was proposed by comparison with the changes of 1H NMR and FTIR spectra of L and its complex. In addition, the potent applicants for probe L were also investigated, and indicated that it could conveniently be made into a series of sensor strips and applied to rapidly detect trace Al³⁺ in traditional Chinese medicine.