Ultrasensitive Immunosensor for Aflatoxin B₁ Detection Based on Screen-Printed Carbon Electrode Modified by Ferrocene @Multi-Walled Carbon Nanotubes

摘要

An electrochemical immunosensor for the ultrasensitive detection of aflatoxin B 1 (AFB 1 ) inagricultural products was developed. Ferrocene (Fc), with favourable oxidation-reduction properties, iswidely used in chemically modified electrodes. Multi-walled carbon nanotubes (MWNTs) have goodcatalytic activity, chemical stability and electronic transport properties. Chitosan (CS) can promotemembrane formation and improve adhesion. Fc was fixed on the surface of a screen-printed carbonelectrode (SPCE) via MWNTs and CS, and then the Fc@MWNT nanostructure was formed. Theincreased specific surface area of SPCE modified by Fc/MWNT/CS facilitated the binding of AFB 1 -BSA, while the excellent electrical conductivity of Fc/MWNT/CS promoted electron transfer. Theseadvantages not only amplified the immunosensor signal but also made the prepared immunosensor havehigh sensitivity, selectivity and stability. Under optimal conditions, the proposed immunosensor obtaineda wide linear range from 10 -3 ~2×10 4 ng/mL and a low AFB 1 detection limit of 0.159 pg/mL via cyclicvoltammetry (CV) and differential pulse voltammetry (DPV). Its stability and effect on actual sampledetection were also proven in this paper. This new immunosensor achieved favourable stability,reproducibility and selectivity and had potential application in real sample analysis.