Advances of the functionalized covalent organic frameworks for sample preparation in food field

[Display omitted] •The types of functionalized COFs were presented.•The recent applications of functionalized COFs in food sample preparation were reviewed.•Functionalization overcame the flaws and enhanced the advantages of COFs.•Functionalization of COFs improved extraction efficiency and selectivity of targets.•The challenges and opportunities in the field were described. Because food contaminants harm human body in varied degrees, accurate detection of them has drawn great interest. Due to the complex matrix effect and the trace level of contaminants, efficient and reliable sample preparation is required before detection. Covalent organic frameworks (COFs) used as extraction materials for sample preparation, displayed great prospect in the food field. However, extraction selectivity and enrichment effect were limited by available COFs. To solve the issues, some COFs were functionalized for specific functions and applications. This paper overviews the main functionalized strategy for COFs, and the applications of functionalized COFs in food field from 2018 to 2022. Different types of species, such as organic group-modified COFs, Fe3O4@COFs, COFs@metal organic frameworks, molecularly imprinted polymer-functionalized COFs, etc., have been introduced in solid-phase extraction and microextraction. These adsorbents effectively captured various analytes from foods. Moreover, challenges and prospects of the functionalized COFs in food sample preparation are presented.