Cheap and easy modification of glassy carbon electrode for voltammetric determination of dopamine in the presence of ascorbic acid

BACKGROUND AND THE PURPOSE OF THE STUDY Different methods have been proposed to modify glassy carbon electrode in order to determine dopamine (DA), as one of the most important neurotransmitters in central nervous systems of mammalian. These methods are time comsuming and in some cases expensive. In this work, a very simple and cheap pretreatment method is developed for the bare glassy carbon electrode (GCE) to determine DA in the presence of Ascorbic acid (AA). METHODS Cyclic voltammetry as an electrochemical activation procedure was used for activation of glassy carbon electrode in order to separate diffrential pulse peaks of DA and AA. The effect of different parameters such as pH for supporting electrolyte, range of potential and the number of cycles were investigated. Finally, differential pulse voltammetry was used to determine DA in the presence of AA. RESULTS On the activated electrode under optimum condition, anodic peak of AA shifted to negative potentials and peak current decreased, but the peak current of DA increased. The peak current was linearly proportional to the bulk concentration of DA in the range of 6.5×10(-7)-1.8×10(-5) mol l(-1). The limit of detection was 6.2×10(-7) mol l(-1). CONCLUSION A simple and cheap method was developed for the activation of glassy carbon electrode. It was possible to determine DA in the presence of AA on the treated electrode. The proposed method was used to determine DA in pharmacutical samples.