DOI: https://doi.org/10.55373/mjchem.v26i5.90

Keywords: Different potentials; glucose; nanogold electrode; screen-printed carbon electrode

Abstract

The properties of screen-printed carbon electrodes (SPCE) with nanogold (AuNP) were ascertained to detect glucose samples. The electrodes were modified with different potentials to obtain suitable potentials for the detection of glucose. The potentials used to prepare gold electrodes were -0.8 V, +0.56 V, and +0.9 V. The bare SPCE acted as a comparison between the bare and the modified SPCE. The modified electrodes (AuNP/SPCE) were characterised using Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX), and X-ray Diffraction (XRD) with deposition at -0.8 V and +0.56 V, proving that the gold nanostructures were deposited at the SPCE surface. The deposition at +0.9 V had an insignificant amount of Au on the SPCE surface, similar to bare SPCE. The active sites and reversibility of the gold electrode can be determined by measuring the electrochemical active surface area (ECSA) of electrode and its anodic and cathodic peak current density ratio (Ipa/Ipc), respectively. The ECSA for modified SPCE with different potentials of -0.8 V, +0.56 V, and +0.9 V were 6.873 cm2, 0.786 cm2, and 0.253 cm2, respectively. The Ipa/Ipc ratio of +0.56 V and -0.8 V showed excellent reversibility and transfer rate compared to +0.9 V. Thus, deposition at -0.8 V and +0.56 V was chosen to detect glucose, and the sensitivity and limit of detection (LOD) were calculated. The sensitivity and LOD for these two modified electrodes (-0.8 V and +0.56 V) were 7.53 mA.mM-1cm-2 and 14.73 mM, as well as 73.38 mA.mM-1cm-2 and 13.13 mM, respectively.