Adaptive polarity of graphene oxide anchored silica doped with C18 for effective enrichment of aflatoxins from foodstuff

Abstract

Selecting adsorbent with appropriate polarity is a practicable way to improve the enrichment efficiency for aflatoxins (AFs) during the solid phase extraction in sample pretreatment. In this study, graphene oxide anchored silica was prepared and applied to dop with C18 with suitable polarity for effective pre-concentration and purification of AFs from foodstuff. With systematic optimizing, GO anchored silica/C18 (1/1, w/w) exhibited excellent extraction performance for AFs. As the medium, a facile and efficient pipette-tip solid-phase extraction (PT-SPE) technique was developed for enrichment of AFs. Coupling with high-performance liquid chromatography fluorescence detection (HPLC-FLD), the developed analysis method illustrated the lower limits of detection of 0.075 ng/g and 0.17 ng/g for AFG2, AFB2 and AFG1, AFB1 (R2 > 0.99). The recoveries were calculated as 71.27 ∼ 94.52 % for the spiking level of 1, 5, and 20 ng/g with the intra-day and inter-day precision of 1.30 to 4.01 and 3.56 to 5.78, respectively. Hence, the developed PT-SPE-HPLC-FLD determination method was sensitive, accurate, and convenient for quantitative analysis of AFs at trace contents in foodstuff.