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

Abstract

This study developed an electrochemical sensor for the determination of Mn²⁺ in Chinese liquor by modifying a glass carbon electrode with TiO₂-NH₂@COF_DPTB, which was synthesized via the controllable growth of COF_DPTB 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@COF_DPTB were carried out by SEM, TEM, HRTEM, EDX, BET, XRD and FTIR techniques. Owing to the excellent properties and the synergism between TiO₂ and COF_DPTB, the introduction of TiO₂-NH₂@COF_DPTB 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 μM with a detection limit of 2.83 × 10⁻¹¹ M and 9.50 × 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.