Simultaneous Determination of Dopamine and L-Ascorbic Acid by Modified Carbon Paste Electrode with Ni (II) Cyclam Complex

Leila Farzin,Mohammad Reza Milani Hosseini

doi:10.4236/ajac.2011.22036

Abstract

The electroanalysis of dopamine (DA) and ascorbic acid (AA) by square wave voltammetry has been performed at a modified carbon paste electrode with macrocyclic ligand 1, 4, 8, 11-tetraazacyclotetradecane (cyclam) and monolayer of Ni (II) cyclam. In pH 7.2 buffer solutions, the electrostatic reaction of AA with di-positive monolayer shifts the oxidation potential to less positive potential, while the electrostatic repulsion of DA with the monolayer shifts the oxidation potential of DA to more positive potential. The separation between the oxidation peaks of AA and DA at the present di-positive monolayer modified electrode (252 mV) was larger than that (187 mV) at the cyclam modified electrode. In addition, the catalytic oxidation of AA by oxidized DA has been advantageously eliminated at the modified carbon paste electrode with cyclam and Ni (II) cyclam complex. Thus, the determination of DA in the presence of an excess of AA is possible with the present modified electrodes.

Highlights

Dopamine (DA) and ascorbic acid (AA) are compounds of great biomedical and neurochemical interest playing a potential role in human metabolism
As the AA concentration, for example, in the extracellular fluid is very high, this mediated oxidation would affect the accurate determination of DA and this unwanted catalytic oxidation needs to avoid
Since the voltammetric peak of DA is well separated from the AA peak, the determination of DA in the presence of AA is possible with the present modified electrode

Summary

Introduction

Dopamine (DA) and ascorbic acid (AA) are compounds of great biomedical and neurochemical interest playing a potential role in human metabolism. DA is one of the most significant catecholamine, functioning as a neurotransmitter in the central nervous system and a medicament to drug addiction and Parkinson’s disease [1,2]. It affects brain processes that control movement, emotional response, and ability to experience pleasure and pain. AA is a water-soluble vitamin that is widely required in metabolism. It has been used in the prevention and treatment of common cold, mental illness, cancer and Aids [3]. In mammalian brain DA and AA coexists in the extracellular fluids

Objectives

Methods

Results

Conclusion