Facile synthesis of dendritic-like CeO₂/rGO composite and application for detection of uric acid and tryptophan simultaneously

Herein, a kind of glassy carbon electrode (GCE) modified with dendritic-like CeO2/reduced graphene oxide composites (CeO2/rGO-GCE) were proposed for uric acid (UA) and tryptophan (Trp) electrochemical simultaneous detection. Crystal structural and morphological characterizations of CeO2/rGO were carried out by X-ray diffraction (XRD), Raman spectrum, X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) techniques. The electrochemical property of UA and Trp on these as-prepared GCE, CeO2-GCE, rGO-GCE, and CeO2/rGO-GCE were investigated by cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). The electrochemical conditions were also discussed for optimal electrochemical performance, such as pH values, scan rate and enrichment parameter. Consequently, the oxidation current peaks of UA and Trp on CeO2/rGO-GCE is 529.6 and 106.7-times higher than bare GCE. It can be attributed to outstanding electrocatalytic performance and large electrochemical active area of dendritic-like CeO2 and rGO. Under the optimal testing condition, in the range of 0.1-20.0 mu M, two detection lines and low limit of detection (LOD) of 13.2 nM (S/N = 3) for UA were obtained. Three wide detection ranges at 0.06-1.0 mu M, 1.0-8.0 mu M and 10-100 mu M were also presented with lower LOD of 5.6 nM (S/N = 3). Moreover, in real human serums samples detection process, this CeO2/rGO-GCE was employed successfully for determination of UA and Trp. These results indicated that this CeO2/rGO-GCE provides a slight view for synthesis of dendritic-like nanomaterials in high-performance electrochemical performance.