Sensitive voltammetric sensor based on polyoxometalate/reduced graphene oxide nanomaterial: Application to the simultaneous determination of l-tyrosine and l-tryptophan

In this report, a novel voltammetric sensor based on polyoxometalate (H3PW12O40, POM) functionalized reduced graphene oxide (rGO) modified glassy carbon electrode (GCE) was presented for simultaneous determination of l-tyrosine (l-Tyr) and l-tryptophan (l-Trp). The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrochemical determination of l-Tyr and l-Trp has been studied using square wave voltammetry (SWV) on GCE modified with POM-rGO composite (POM-rGO/GCE). The developed method was also applied successfully for the simultaneous determination of l-Tyr and l-Trp in spiked serum sample and the linearity range of l-Tyr and l-Trp was 1.0 × 10-11 - 1.0 × 10-9 M with the detection limit of 2.0 × 10-12 M. © 2016 Elsevier B.V. All rights reserved.