Abstract: Graphene nanosheets (GNs), which were prepared by liquid-phase exfoliation method, were directly casted onto the surface of a glassy carbon electrode to obtain a graphene-modified electrode (GN/GCE). Then, the polypyrimidine/ graphene composite film modified electrode (pAMP/GN/GCE) was fabricated by electrodeposition method. The surface morphology of the modified electrode was characterized by scanning electron microscope. Electrochemcial behaviors of sunset yellow (SY) and tartrazine (TT) on pAMP/GN/GCE were investigated with cyclic voltammetry (CV) and square wave voltammetry (SWV). The experimental results showed that the as-prepared electrode exhibited remarkable catalytic ability for both SY and TT. Under the optimized experimental conditions, the linear ranges for detecting SY and TT were 0.002–2 mmol/L and 0.003–6 mmol/L, respectively. The limits of detection (LODs) were as low as 0.5 and 0.9 nmol/L (RSN = 3), respectively. This developed method can be used for the simultaneous determination of SY and TT in food samples.

Key words: graphene, 4-amino-2-mercaptopyrimidine, sunset yellow, tartrazine, electrochemical sensor