A Simple Electrochemical Immunosensor for Highly Sensitive Detection of Aflatoxin B1 Based on Gold Nanoparticle Decorated Carboxylated Graphene Oxide

In this work, polycrystalline gold nanoparticles decorated carboxylated graphene oxide (Au-COOH-GO) nanohybrids have been prepared and were used to fabricate electrochemical immunosensor for detecting of aflatoxin B-1 (AFB(1)). The obtained Au-COOH-GO nanohybrids are characterized by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and UV-vis absorption spectra. Each step of the immunoelectrode design is evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The surface reaction mechanism of AFB(1) on Au-COOH-GO nanohybrids also has been investigated. The concentration and incubation time of antibody, pH, and immunoreaction time are optimized by square wave voltammogram (SWV). Under the optimal conditions, the detection limit of AFB(1) is 0.05 ng mL(-1) (S/N=3) with a linear AFB(1) concentration range of 0.05 to 25 ng mL(-1). The fabricated immunosensor shows a good reproducibility, stability, and selectivity and can successfully detect AFB(1) in real rice sample.