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.
