Quinoline derivative with fluorescent off-on function for Fe3+ and oxalic acid

A fluorescent molecular probe (L) based derivative of quinoline Schiff base was synthesized by condensation of 8-hydroxyquinoline-2-carboxaldehyde and salicylhydrazide. Probe L was characterized by FTIR, 1HNMR, 13CNMR and ESI-MS. The recognition performance of probe L was studied by absorption and fluorescence spectra. Probe L and Fe3+ could form 1∶1 (molar ratio) complex L-Fe in dimethyl sulfoxide with apparent binding constant of 4.6×104 L/mol. Through the fluorescence quenched of probe caused by the formation of the above complex, Fe3+ could be selectively recognized in common metal ions, and the detection limit was 6.8×10-8 mol/L. Furthermore, complex L-Fe was used as a probe to achieve highly selective fluorescence enhanced recognition of oxalic acid, and the detection limit was 1.3×10-7 mol/L. This method can be used to detect oxalic acid in spinach. © 2020, Editorial Office of FINE CHEMICALS. All right reserved.