Simultaneous determination of aflatoxin B1 and zearalenone by magnetic nanoparticle filled amino-modified multi-walled carbon nanotubes

Abstract

A novel magnetic solid-phase extraction (MSPE) coupled with high performance liquid chromatography (HPLC) method was explored for aflatoxin B1 (AFB1) and zearalenone (ZON) simultaneous determination. This method was based on a newly explored extractant of Fe₃O₄ nanoparticle-filled amino-modified multi-walled carbon nanotubes (Fe₃O₄-MWCNTs-NH₂) composite, which was sensitive to analytes with structure of multi-aromatic rings and abundant hydrogen bond acceptors, based on the extraction mechanism of π–π EDA and hydrogen-bonding interactions. The morphology, structure and magnetic properties of the extractant were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). Adsorption isotherms and kinetics for two mycotoxins were investigated and proved to be the best fit by Dubinin–Astakhov and pseudo-second-order models. Critical MSPE parameters, including solution pH, extraction time, salt addition and temperature, were investigated and optimized and the proposed analytical method was validated. Subsequently, the method was successfully applied for AFB1 and ZON analysis from wheat flour samples. The proposed method proved to be an excellent green analysis with a score of 89 in analytical Eco-Scale evaluation. It also has good linearities in the range of 1.0–100.0 ng g⁻¹ with linear coefficients (r) above 0.99, desirable recoveries ranging from 88.8% to 96.0%, satisfactory precision with relative standard deviation (RSD) in the range of 2.1–2.8%, and low limits of detection (LODs) of 0.15 and 0.24 ng g⁻¹ for AFB1 and ZON, respectively. This novel magnetic-extractant-based green MSPE-HPLC method has great potential for mycotoxin analysis from complex matrix samples.