A facile preparation of Au—SiO2 nanocomposite for simultaneous electrochemical detection of dopamine and uric acid

Abstract

We report an electrochemical biosensor based on Au—SiO2 nanocomposite for the detection of dopamine and uric acid. The nanocomposite was prepared by a simple wet chemical process and the characterisation was carried out using transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Cyclic voltammetry (CV) was used to assess the electrocatalytic response of Au-SiO2/GCE towards dopamine and uric acid. Compared to Au/GCE and SiO2/GCE, the Au-SiO2/GCE exhibited high electrocatalytic response which is attributed to the increased surface area and conductivity of the nanocomposite. The detection of dopamine and uric acid was performed by using differential pulse voltammetry (DPV) which displayed two linear ranges from 10 μM-100 μM and 200 μM-500 μM with a detection limit of 1.98 μM for dopamine and a linear range from 10 μM-500 μM with a detection limit of 2.58 μM for uric acid. The simultaneous detection of dopamine and uric acid was carried out which showed a peak to peak separation of 215 mV. The sensor showed excellent sensitivity for dopamine and uric acid with good stability and reproducibility. Further, the detection of dopamine and uric acid in serum sample analysis was performed successfully with satisfactory recovery values.