Electrochemical sensor based on modified methylcellulose by graphene oxide and Fe3O4 nanoparticles: Application in the analysis of uric acid content in urine

The modified glassy carbon electrode (GCE) with a coating containing methylcellulose/graphene oxide/iron oxide nano hydrogel (MC-GO-Fe3O4) has been developed to design a high-performance electrochemical bioassay system. The influence of each component of the modifier was investigated separately. This comparison showed that exist of all components in modification has a synergistic effect. MC-GO-Fe3O4 nanocomposite has a larger surface area and provides a more fine-grained media to facilitate electron transfer during the reaction between analyte and electrode. The modified GCE was used for the electrooxidation of uric acid (UA) as a model analyte by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. It exhibits a diffusion-controlled process with a two-electron, two-proton transfer reaction. The ability of the developed electrode to measure UA was studied and it has been found a linear dependence on UA concentration with a linear amplitude of 0.5–140 μM and a limit of detection of 0.17 μM. According to the results, the GCE|MC-GO-Fe3O4 provides an accurate and precise assay pathway of UA in the urine sample.