Fluorescent schiff base probes for sequential detection of Al³⁺ and F^- and cell imaging applications

Two novel Schiff-base fluorescent probers SQ and NQ based on 8-hydroxyquinoline moiety were designed and synthesized. The both probes were capable of binding with Al³⁺ by naked eye detection to produce a significant fluorescence enhancement response with a detection limit of 1.48 × 10^-8 and 4.23 × 10^-8 M, respectively. At the same time, the formed complexes SQ-Al³⁺ and NQ-Al³⁺ could sequentially detect F^-, and the detection limits of F^- were determined to be 1.64 × 10^-7 and 3.58 × 10^-8 M, respectively. The "off-on-off" fluorescence response process demonstrated that the binding were reversible. The probes were further successfully utilized to detect Al³⁺ and F^- in vitro PC12 cells.