Highly stable and ultra-sensitive amperometric aptasensor based on pectin stabilized gold nanoparticles on graphene oxide modified GCE for the detection of aflatoxin M1

International audience ; Herein, we have elaborated a new electrochemical aptasensor for the detection of ultra-trace amounts of aflatoxin M1 (AFM 1) present in cow milk, with regulated low levels. To achieve detection of AFM 1 , a simple strategy for the deposition of specific aptamers was elaborated, based on their grafting on pectin-reduced gold nanoparticles (AuNPs) electrogenerated on a graphene oxide sheet modified glassy carbon electrode. The elaboration of composite film was confirmed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and UV-visible absorption measurements. The aptamer/pectin-AuNPs/GO/GCE exhibited significantly enhancement in the determination of AFM 1 in 20 min with a low detection limit 0.2 ng/L, a wide and useful linear range (10-1000 ng/L). An excellent stability, a high sensitivity, and a reproducibility as well as good recovery were obtained by the designed aptasensor. Moreover, the obtained results were tested in real samples. Thus, good electrochemical performance and simple preparation process of the aptamer/pectin-AuNPs/GO/GCE can provide promising potential for the detection of AFM 1 in milk samples in a daily use.