A high performance covalent organic framework material assists metabolomics in the detection of mycotoxin infection in wheat.

Wheat contamination by aflatoxin B1 (AFB1) poses a serious threat to food security and human health due to its potent carcinogenicity. However, conventional analytical methods are limited by complex sample pretreatment and post-contamination analysis, lacking early warning capability. Herein, we developed a highly crystalline hydroxyl-functionalized covalent organic framework (COF1) as an interference-free laser desorption/ionization mass spectrometry (LDI-MS) substrate for metabolomics profiling and early monitoring for AFB1 infection in wheat. Compared with traditional organic matrices and low-crystallinity COF (COF2), COF1 exhibited excellent auxiliary desorption/ionization performance and successfully acquired metabolic fingerprints of 120 wheat samples (60 AFB1-infected and 60 healthy controls) without complicated pretreatment, clearly revealing metabolic divergence between the two groups. Furthermore, 11 candidate biomarkers were screened by multivariate statistical analysis and their roles in the metabolic pathway responses under mycotoxin stress were preliminarily elucidated. This work offers a rapid and reliable strategy for early risk screening of mycotoxins in wheat.