In-situ stabilization of conjugated microporous polymer on sieve plates for multifunctional applications: Detection and removal of aflatoxins.

Aflatoxins (AFTs) are increasingly recognized as significant contributors to environmental and food pollution, posing a serious threat to human health and public safety. The advancement of materials capable of both detection and removal of aflatoxins presents considerable challenges within the realm of food safety. In this study, the conjugated microporous polymer (CMP) was firstly introduced as the adsorbent for AFTs. A conjugated microporous polymer (CMP)-based sieve plate was synthesized through in-situ growth. Systematic characterization demonstrated that the CMP with excellent hydrophobicity was homogeneously bound to the PE plate. Subsequently, a miniaturized CMP-based pipette-tip micro solid-phase extraction (CMP-PT-μSPE) device was designed for the efficient enrichment of AFTs from sample extract in just 2 min. It can cycle over 10 times without requiring additional equipment, showing significant potential to reduce reagent and sorbent usage, and simplify labor-intensive procedures. A CMP-PT-μSPE-HPLC method for AFTs was successfully established, achieving recoveries ranging from 78.2 % to 100.5 % and the limits of detection (LODs) and the limits of quantification (LOQs) within the ranges of 0.01-0.14 μg/kg and 0.03-0.47 μg/kg, respectively. Furthermore, the CMP-based sieve plate, possessing excellent adsorption capacity for AFTs, serves as an effective adsorbent for the detoxification of contaminated vegetable oils with AFTs concentrations of 100 μg/kg. After a 4 h of contact period at 30 °C, the AFTs levels in the treated oils were found to be compliant with the regulatory limits for vegetable oils. Additionally, the CMP-based sieve plate demonstrated a high level of stability and universality in AFTs detoxification of vegetable oils, with low cytotoxicity and minimal effects on the quality of oils, and it also showed notable simplicity, scalability, and versatility. The Density Functional Theory (DFT) simulation revealed that the values of adsorption energies for the CMP-AFB1, CMP-AFB2, CMP-AFG1, and CMP-AFG2 complexes were -10.98, -10.93, -9.32, and -7.93 kcal/mol, respectively. X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FT-IR) and DFT analysis revealed that there were five types of interactions between CMP and AFTs, including H-π interaction, π-π stacking dispersion interaction, π-π dispersion interaction arising from π electrons (furan ring) interacting with π electrons (CC), and π electrons (carbonyl structure) interacting with π electrons (CC), as well as π electrons (carbonyl structure) interacting with π electrons (benzene ring). This research not only proposes an innovative green strategy for the simultaneous detection and removal of AFTs but also offers critical insights into the adsorption mechanisms associated with the binding of AFTs to the π-conjugation skeleton.