An electrochemical sensor based on a Co 3 O 4 -ERGO nanocomposite modified screen-printed electrode for detection of uric acid in artificial saliva.

In this study, we report the fabrication of a nanocomposite consisting of Co 3 O 4 nanoparticles (Co 3 O 4 NPs) and electrochemically reduced graphene oxide (ERGO) on a screen-printed electrode (SPE) and its sensing performance in the electrochemical detection of uric acid (UA). The surface modification of the electrode was confirmed by using a variety of characterization techniques (FE-SEM, XRD, AFM, EDX, WCA, FTIR, and Raman spectroscopy). In addition, the surface modification was electrochemically characterized step by step through CV, EIS and DPV techniques, and the results showed that the Co 3 O 4 -ERGO nanocomposite exhibited highly sensitive and selective sensing performance towards the oxidation of UA in 0.1 M (pH 7.0) phosphate buffer solution (PBS). The sensor (Co 3 O 4 -ERGO/SPE) signals were observed to be linear to the UA concentration in the range of 5 μM to 500 μM ( R 2 = 0.9985). After revealing its other performance characteristics, such as repeatability, reproducibility, stability, sensitivity, and selectivity, the sensor was successfully applied to the analysis of UA in artificial saliva samples.