Magnetic nitrogen-doped reduced graphene oxide as a novel magnetic solid-phase extraction adsorbent for the separation of bisphenol endocrine disruptors in carbonated beverages.

A novel magnetic nitrogen-doped reduced graphene oxide (Fe3O4@N-RGO) had been fabricated for the first time on the basis of a simple solvothermal method and then was successfully applied to extract four bisphenol endocrine disruptors (bisphenol A, bisphenol B, bisphenol F and bisphenol AP) in carbonated beverages coupled with high performance liquid chromatography (HPLC). The as-prepared Fe3O4@N-RGO was characterized by transmission electron microscopy (TEM), Brunner-Emmet-Teller (BET), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS) and vibrating sample magnetometer (VSM). The introduction of nitrogen atoms not only made the wrinkle level of N-RGO increased, but also retarded the irreversible aggregation of graphene sheets. Compared with Fe3O4@RGO, Fe3O4@N-RGO owned larger specific surface area and more adsorption sites. Hence, Fe3O4@N-RGO showed excellent extraction efficiency toward bisphenol endocrine disruptors. The analytical parameters influencing the extraction efficiency were optimized in detail. Under the optimal conditions, a satisfactory performance was obtained. The calibration lines were linear over the concentration in the range of 0.4-1000 μg L-1 with determination coefficients (r2) between 0.9976 and 0.9996. The limits of detection (LOD) ranged from 0.1 μg L-1 to 0.2 μg L-1. The recoveries varied from 86.52% to 101.47% with relative standard deviations (RSDs) less than 8.59%. Overall, the proposed method was an efficient pretreatment and enrichment procedure and could be successfully applied for selective extraction and determination of bisphenol endocrine disruptors in complex matrices.