Fabrication of a Magnetic Functionalized Chitosan Hydrogel for Effective Extraction of Aflatoxins from Cereals

Abstract

A magnetic adsorbent was synthesized by coupling magnetic nanoparticle, UiO-66-NH2 and 1-butyl-trimethylimidazole bromide ([BMIM][Br]) to chitosan (CS)-based composites conveniently. A series of modern technologies were performed to characterize the adsorbent. Results showed that UiO-66-NH2 was uniformly distributed in the composite via in-situ grown. The addition of rigid UiO-66-NH2 ligand can increase the stability and porosity of the adsorbent, thus reduce mass transfer resistance. The introduction of [BMIM][Br] and CS enables the adsorbent to exhibit good dispersion in water and excellent extraction performance for four aflatoxins. The detection limits ranged from 0.08 to 0.56 μg/kg with good repeatability. The established method was successfully utilized to determine aflatoxins from six cereal samples (rice, glutinous rice, wheat, soybean, paddy, and corn) with satisfactory recovery of 77%-119% and relative standard deviation of 1.0%-11.7%. The adsorbent was robust enough for repeatable use at least 6 times without obvious damage of extraction property.

Keywords: Chitosan, Metal organic framework, ion liquid, Magnetic solid phase extraction, Aflatoxin, cereal