Simple flame etching of pencil electrode for dopamine oxidation in presence of ascorbic acid and uric acid

Abstract

The simple graphite pencil electrode (GPE) tip was etched by burning it using match stick. A dark black coloured deposition was observed in the etched portion. This etched portion of GPE was subjected to characterisation by X-ray diffraction (XRD), and Scanning Electron Microscopy. Further this etched electrode was used for simultaneous investigation of dopamine and ascorbic acid in 0.2 M phosphate buffer of pH 7.4. The modified GPE was stable and reproducible towards detection of dopamine. The stability of this flame etched electrode towards dopamine was characterised by applying multiple cycles. The effect of scan rate was found to be adsorption-controlled electrode process. The detection limit was found to be 3.4708 × 10-7 M and quantification limit was found to be 11.5693 × 10-7 M. The flame etched electrode applied for the detection of dopamine in presence of ascorbic acid and uric acid. The electrode showed excellent selectivity for the resolution of dopamine, ascorbic acid and uric acid with respective oxidation and reduction peak potentials. The effect of interference was examined by varying the concentration of one species while other two were kept constant by using differential pulse voltammetric technique.