A comparative study of different Fe3O4-functionalized carbon-based nanomaterials for the development of electrochemical sensors for bisphenol A

No work studied and compared Fe3O4-functionalized carbon-based nanomaterials. Also, no work investigated their application for detecting bisphenol A (BPA), an important organic chemical raw material, which had been proved to cause malformation, cancers, sexual precocity, and neural and behavioral changes in infants and children. In this work, Fe3O4 magnetite nanoparticles were stably anchored on carbon materials to synthesize three types of nanohybrids, i.e. hybrids of graphene oxide with Fe3O4 (GO-Fe3O4), carbon nanotubes with Fe3O4 (CNTs-Fe3O4), and graphene oxide and carbon nanotubes with Fe3O4 (GO-CNTs-Fe3O4). These nanohybrids were characterized using a transmission electron microscope (TEM), X-ray diffractometer (XRD), and Fourier transform infrared spectrometer (FT-IR). GO-Fe3O4, CNTs-Fe3O4, and GO-CNTs-Fe3O4 were immobilized on the surface of a GCE using electro-poly(glutamic acid). The electrochemical response characteristic of bisphenol A (BPA) on different modified electrodes was investigated by cyclic voltammetry. It showed that these three types of nanohybrids greatly enhanced the anodic peak current of BPA. Then, these hybrids were applied to determine BPA by differential pulse voltammetry. Their determination performance was compared with each other. Among them, the GO-CNTs-Fe3O4 modified electrode exhibited wider linear ranges of 0.003-0.2 and 0.2-30.0 mu mol L-1 with a lower estimated detection limit of 1.0 nmol L-1.