Graphene oxide: An adsorbent for the extraction and quantification of aflatoxins in peanuts by high-performance liquid chromatography

• Graphene oxide (GO) was successfully synthesized and used as an adsorbent for extraction of four aflatoxins.
• The aflatoxins extraction efficiency for GO has been investigated.
• A method of HPLC-FLD coupled with GO as adsorbent has been developed for the simultaneous determination of four aflatoxins in peanut samples.

In this paper, graphene oxide (GO) was synthesized and specifically selected by centrifugation to extract four aflatoxins (B1, B2, G1, and G2) as an effective adsorbent. Then, the amount of aflatoxins was quantitatively measured by high-performance liquid chromatography (HPLC). The GO was characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), and ultraviolet (UV) spectrophotometer. Several parameters that could affect the extraction efficiency, including the GO amount, methanol concentration in the extraction solvent, spiked amount, extraction time, and elution cycle, were also investigated and optimized in this work. Under optimal conditions, good linear relationships were achieved with the correlation coefficient (r) ranging from 0.99217 to 0.99995. The detection limit of this method for the four aflatoxins ranged from 0.08 to 0.65 ng/g. Finally, the proposed method has been successfully applied to determine aflatoxins in peanut samples. The results show that the recoveries of the four aflatoxins range from 85.1% to 100.8% with the relative standard deviations between 2.1% and 7.9%.