Simultaneous voltammetric determination of tyrosine and paracetamol using a carbon nanotube-graphene nanosheet nanocomposite modified electrode in human blood serum and pharmaceuticals

A novel, simple and selective electrochemical method was investigated for the single or simultaneous determination of tyrosine (Tyr) and paracetamol (PC) in aqueous media (phosphate buffer solution, pH 7.5) on MWCNTs-graphene nanosheet nanocomposite modified glassy carbon electrode (MWCNTs-GNS/GCE) using differential pulse voltammetry (DPV). The MWCNTs-GNS/GCE displayed high effective surface area, high porosity, more reactive sites and excellent electrochemical catalytic activity toward the oxidation of Tyr and PC. The peak current of differential pulse voltammograms of Tyr and PC increased linearly with their concentration in the ranges of 0.90-95.4 mu M Tyr and 0.80-110.0 mu M PC. The detection limits for Tyr and PC were 0.19 mu M and 0.10 mu M, respectively. The proposed sensor was successfully applied for the determination of Tyr and PC in human blood serum and pharmaceutical samples. (c) 2012 Elsevier B.V. All rights reserved.