Adsorption of aflatoxins and ochratoxins in edible vegetable oils with dopamine-coated magnetic multi-walled carbon nanotubes.

A new, green, and cost-effective magnetic solid-phase extraction of aflatoxins and ochratoxins from edible vegetable oils samples was developed using polydopamine-coated magnetic multi-walled carbon nanotubes (PDA@Fe3O4-MWCNTs) as the absorbent. PDA@Fe3O4-MWCNTs nanomaterials were prepared by chemical co-precipitation and in situ oxidation and self-polymerization of dopamine and was characterized. Factors affecting MSPE and the adsorption behavior of the adsorbent to mycotoxins were studied, and the optimal extraction conditions of MSPE and the complexity of the adsorption process were determined. Based on this, the magnetic solid-phase extraction-high-performance liquid chromatography-fluorescence detection method (MSPE-HPLC-FLD) was established for determining six mycotoxins [aflatoxin B1 (AFB1), AFB2, AFG1, and AFG2, and ochratoxin A (OTA) and OTB)] in vegetable oils. The recovery was 70.15%~89.25%, and RSD was ≤6.4%. PDA@Fe3O4-MWCNTs showed a high affinity toward aflatoxins and ochratoxins, allowing selective extraction and quantification of aflatoxins and ochratoxins from complex sample matrices.