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 TiO 2 -graphene (TiO 2 -GR) nanocomposite, and its voltammetric response to the amino acids L-tryptophane (Trp) and L-tyrosine (Tyr). The incorporation of TiO 2 nanoparticles with graphene significantly improves the electrocatalytic activity and voltammetric response compared to electrodes modified with Nafion/graphene only. The Nafion/TiO 2 -GR modified electrode was used to determine Trp and Tyr with detection limits of 0.7 and 2.3 μM, and a sensitivity of 75.9 and 22.8 μA mM −1 for Trp and Tyr, respectively. The electrochemical sensor based on Nafion/TiO 2 -GR composite film modified GCE was presented. The integration of TiO 2 nanoparticles with graphene provides an efficient microenvironment to promote the electrochemical reaction of amino acids Trp and Tyr. The fabricated electrochemical sensor exhibits favorable analytical performance for Trp and Tyr, with high sensitivity, low detection limit and good reproducibility.