Electrochemistry and voltammetric determination of L-tryptophan and L-tyrosine using a glassy carbon electrode modified with a Nafion/TiO2-graphene composite film

We describe a glassy carbon electrode (GCE) modified with a film composed of Nafion and TiO2-graphene (TiO2-GR) nanocomposite, and its voltammetric response to the amino acids L-tryptophane (Trp) and L-tyrosine (Tyr). The incorporation of TiO2 nanoparticles with graphene significantly improves the electrocatalytic activity and voltammetric response compared to electrodes modified with Nafion/graphene only. The Nafion/TiO2-GR modified electrode was used to determine Trp and Tyr with detection limits of 0.7 and 2.3 mu M, and a sensitivity of 75.9 and 22.8 mu A mM(-1) for Trp and Tyr, respectively.