GQDs/PEDOT Bilayer Films Modified Electrode as a Novel Electrochemical Sensing Platform for Rutin Detection

A glassy carbon electrode (GCE) modified with graphene quantum dots (GQDs) and poly (3, 4- ethylenedioxythiophene) (PEDOT) bilayer films (GQDs/PEDOT/GCE) was constructed and used as a novel electrochemical sensor for rutin detection. The GQDs/PEDOT/GCE sensor was fabricated by two- step electrodeposition and was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Compared with individual GQDs/GCE and PEDOT/GCE, the current response of the composite electrode to rutin increased by about 10 times and 3 times respectively. The composite electrode exhibited a strong electrical response toward rutin redox due to the cooperative action of the large surface area of the GQDs which allowed strong analyte adsorption and the high electroconductivity of PEDOT. The current response of the GQDs/PEDOT/GCE electrochemical sensor was more linear at rutin concentrations between 0.05 μM and 10 μM and had a detection limit of 11 nM. The sensor also presented a high selectivity, high stability, and excellent recovery rate and could be used for the effective and reliable analysis of rutin in real samples.