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

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.