Phenyl-imidazole based and nitrogen rich hyper-crosslinked polymer for sensitive determination of aflatoxins

• Three nitrogen rich hyper-crosslinked polymers (N-HCPs) were synthesized. • The novel N-HCPs exhibited remarkable capability to extract aflatoxins (AFs). • N-HCP was used as sorbent for detecting trace AFs in rice and fragrant rice. • A sensitive method was developed for simultaneous determination of four AFs in grain. • Adsorption mechanism and human health risk assessment were studied. Using heterocyclic phenyl-imidazole (2-phenylimidazole, 4,5-diphenylimidazole and 2,4,5-triphenylimidazole) as monomer, three novel hyper-crosslinked polymers (PI-HCP, DPI-HCP and TPI-HCP) with large specific surface area and excellent chemical stability were fabricated by Friedel-Crafts reaction. With PI-HCP as solid phase extraction adsorbent, a high performance liquid chromatography-fluorescence detection method was developed for sensitive determination of aflatoxins B 1 , B 2 , G 1 and G 2 in rice and fragrant rice samples. Under optimized conditions, the established method provided wide linear range, low detection limit and satisfactory recovery. Moreover, the adsorption mechanism was also explored. The polar interaction, hydrogen bonding and π-π stacking interactions between PI-HCP and AFs might be the main adsorption mechanisms. This work provides a powerful tool for simultaneous determination of four AFs in food grains with great application potential in AFs monitoring.