Extraction of short-chain fatty acid ethyl Ester in Baijiu using covalent organic framework-based magnetic nanoparticles: Theoretical screening and experimental validation.

Short-chain fatty acid ethyl esters (SFAEEs) are critical aroma compounds in Baijiu, and their wider concentration range can lead to differences in the quality grade of Baijiu. Efficiently designing an SFAEEs adsorbent before instrument analysis remains challenging. In this work, nine functionalized covalent organic frameworks (COFs) with different postmodification groups were designed for targeting SFAEEs. Based on interaction energy as the evaluation criterion, COFs modified with 5-Mercapto-1-methyltetrazole (MMTZ) had been identified through density functional theory screening. Using imine COFs and MMTZ, novel magnetic nanoparticles (Fe3O4@COFs@MMTZ) were prepared and used to develop the magnetic solid-phase extraction of SFAEEs from Baijiu. The adsorption mechanism of Fe3O4@COFs@MMTZ was analyzed using wave function analysis, revealing that adsorption occurred via vdW interaction, CH···π interaction, and hydrogen bonding. This study provides a new concept for the rapid detection of SFAEEs and theoretical support for the scientific construction of quality control during Baijiu production.