Sodium Dodecyl Sulfate Modified Pencil Graphite Electrode Sensor for Dopamine Oxidation in Presence ofAscorbic Acid

Abstract

The graphite pencil electrode was modified with sodium dodecyl sulfate, an anionic surfactant, for simultaneous investigation of dopamine and ascorbic acid in 0.2 M phosphate buffer of pH 7.4. The modified graphite pencil electrode was stable and reproducible towards detection of dopamine. The effect of scan rate was found to be adsorption-controlled electrode process. The effect of concentration and pH effect were studied. The detection limit and quantification limit were found to be 0.1 µM and 0.333 µM. The modified electrode separated the dopamine and ascorbic acid with peak to peak separation of 110 mV. The effect of interference was done by varying the concentration of one species while other two are kept constant by using differential pulse voltammetric technique. The proposed method was applied to the detection of dopamine in injection samples.