Highly efficient determination of Mn²⁺ in Chinese liquor by using a novel electrochemical sensor based on TiO₂-NH₂@covalent organic framework nanocomposites

This study developed an electrochemical sensor for the determination of Mn2+ in Chinese liquor by modifying a glass carbon electrode with TiO2-NH2@COFDPTB, which was synthesized via the controllable growth of COFDPTB onto the surface of TiO2-NH2 using the Schiff-base condensation reaction between 2,5-dimethoxyterephthalaldehyde and 1,3,5-tris(4-aminophenyl)benzene. The morphological and structural characterization studies of the proposed TiO2-NH2@COFDPTB were carried out by SEM, TEM, HRTEM, EDX, BET, XRD and FTIR techniques. Owing to the excellent properties and the synergism between TiO2 and COFDPTB, the introduction of TiO2-NH2@COFDPTB improved the electrochemical response significantly. By optimizing the experimental parameters, the sensor exhibited good linearity in the range of 0.1-1.0 nM and 0.08-10 mu M with a detection limit of 2.83 x 10(-11) M and 9.50 x 10(-9) M, respectively, showing competitive performance for Mn2+ determination. Besides, the proposed sensor was successfully applied to Mn2+ detection in liquor samples, suggesting its practical application performance.