Fabrication of an ultrasensitive impedimetric electrochemical sensor based on graphene nanosheet/polyethyleneimine/gold nanoparticle composite

In this study, graphene nanosheet/polyethyleneimine/gold nanoparticle (GN/PEI/AuNP) composite modified glassy carbon (GC) electrode has been utilized as a platform to immobilize poly acriflavine (PAF). PEI, a cationic polymer, was used both as a non-covalent functionalizing agent for the graphene oxide (GO) nanosheets through electrostatic interactions in the aqueous medium and also as a stabilizing agent for the formation of AuNPs on PEI wrapped GNs. The prepared GN/PEI/AuNP composite exhibits the dispersion of high density AuNPs which were densely decorated on the large surface area of the PEI wrapped GNs. The surface structure and composition of the sensor were characterized by scanning electron microscopy (SEM). Electrocatalytic reduction of iodate on the surface of modified electrode was investigated with cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and chronoamperometry methods. The cyclic voltammetric results indicated the ability of GN/PEI/AuNP/PAF modified GC electrode to catalyze the reduction of iodate.