A simple fluorescent probe for selectively detecting Al3+ and F− in living cells and growing tea plants†

Aluminum (Al³⁺) and fluorine (F⁻) ions can be easily enriched in tea plants. When they excessively accumulate in tea, they can affect the health of tea lovers. Herein, a simple, highly sensitive and selective fluorescent probe (named BHMP) for Al³⁺ and F⁻ detection was developed through a one-step condensation reaction, in which benzothiazole acted as a fluorophore and acceptor and hydrazine-Schiff base as a recognition unit. The probe was characterized comprehensively using spectroscopic methods, and the structure–activity relationship was systematically researched through crystal structure and theoretical calculations. Its sensitivity was measured via the fluorescent titration experiment, and the limit of detection (LOD) towards Al³⁺ was up to 1.04 × 10⁻⁸ mol L⁻¹. Furthermore, we successfully utilized BHMP to visually detect the presence of Al³⁺ in living cells and tea tree roots through fluorescence confocal imaging. The successful detection of Al³⁺ in tea tree roots indicated that BHMP could be used as a candidate fluorescent chemosensor to dynamically monitor the variation in enriched Al³⁺ under the influence of the environment during tea tree growth. Our study provides a reference for the control of Al³⁺ concentration during the growth of tea plants and provides new insights into improving tea quality control.