High efficient adsorption of aflatoxins in peanuts by novel covalent organic framework through multiple interactions

Aflatoxins are the most toxic and high-profile mycotoxins with high occurrence in grain and nuts. To effectively adsorb and sensitively detect aflatoxins in peanuts, two novel covalent organic frameworks (TF-COF, TH-COF) were fabricated by Schiff-base reaction of N,N,N′,N′-tetra ( p -aminophenyl)- p -phenylenediamine with 2,3,5,6-tetra-fluoroterephthaldehyde and terephthalendehyde, respectively. The TF-COF shows higher adsorption capacity (35–44 mg g −1 ) for aflatoxins than TH-COF (26–37 mg g −1 ) because abundant fluorine functional groups in TF-COF offer more adsorption sites. A sensitive and practical method for determining aflatoxins (G 2 , G 1 , B 2 and B 1 ) in peanuts was developed by combining TF-COF-based extraction technology with high performance liquid chromatography-fluorescence detector. The method provides outstanding performance with linear range of 0.025 ng g −1 -20.0 ng g −1 , detection limits of 0.008 ng g −1 -0.15 ng g −1 , recovery of 86.3 %–116 %, and relative standard deviation below 7.8 %. This study opens a new avenue to develop functionalized COF with distinguished performance for adsorbing hazards in food and/or environmental samples.