One-step electrochemical approach for the preparation of graphene wrapped-phosphotungstic acid hybrid and its application for simultaneous determination of sunset yellow and tartrazine

We have demonstrated a one-step and effective electrochemical method to prepare graphene (GN) layer-wrapped phosphotungstic acid (PTA) hybrid on the surface of glassy carbon electrode (GCE) using graphene as an electron transfer mediator. The PTA coupled with graphene provides good selectivity and high sensitivity for the simultaneous determination of two synthetic food colorants, sunset yellow and tartrazine, exhibiting as well-defined oxidation peaks in differential pulse voltammetry with a peak potential separation of ca. 260 mV. The detection limit was found to be 0.5 mu g L-1 for sunset yellow and 30.0 mu g L-1 for tartrazine. The interference of some common food additives was studied and it was concluded that application of this method for the determination of sunset yellow and tartrazine in several commercial soft drink samples led to satisfactory results. This study provides useful further evidences for the development of portable sensors for food additives. (C) 2012 Elsevier Ltd. All rights reserved.