Determinacion De La Dopamina En Presencia De Acido Urico

American Journal of Analytical Chemistry, 2011, 2, 262-269
doi:10.4236/ajac.2011.22032 Published Online May 2011 (http://www.SciRP.org/journal/ajac)

Determination of Dopamine in Presence of Uric Acid at Poly (Eriochrome Black T) Film Modified Graphite Pencil Electrode
Umesh Chandra, Bahaddurghatta Eshwaraswamy Kumara Swamy*, Ongera Gilbert, Sathish Reddy, Bailire Sheena Sherigara
Departmentof PG Studies and Research in Industrial Chemistry, Kuvempu University, Karnataka, India E-mail: kumaraswamy21@yahoo.com Received December 26, 2010; revised April 1, 2011; accepted April 2, 2011

Abstract
A simple commercial graphite pencil electrode was used to investigate the electrochemical oxidation of dopamine. The electropolymerised film of eriochrome black T was prepared on the surfaceof graphite pencil electrode by using cyclic voltammetry technique. The prepared electrode exhibits an excellent electrocatalytical activity towards the determination of dopamine. The effects of concentration, pH and scan rate were investigated. Simultaneous detection of dopamine and uric acid was investigated by using both cyclic voltammetric and differential pulse voltammetry technique. Themodified electrode was also used for the detection of dopamine in injection. Keywords: Poly (Eriochrome Black T), Graphite Pencil Electrode, Dopamine, Uric Acid, Cyclic Voltammetry, Differential Pulse Voltammetry

1. Introduction
Dopamine is an important neurotransmitter in the amygdala, a phylogenetically older structure of the brain, which is thought to play a critical role in limbic, cognitiveand neuroendocrine functions [1,2]. Serious diseases such as Schizophrenia and Parkinsonism may result by loss of DA-containing neurons [3-8]. Patient with this disease shows a low level of DA. Therefore, determination of DA concentration has become important. Many methods were introduced to determine DA, such as spectroscopy, chromatography and electrochemistry [9-13]. Because of itselectrochemical activity, DA can also be determined with electrochemical method [7,14]. Uric acid (UA) is the primary end product of purine metabolism in the human body [15]. In a healthy human being, the typical concentration of UA in urine is around 2 mM and in the blood is in between 120 μM to 450 μM ranges [16,17]. Extreme abnormalities of UA levels are symptomic of several diseases, such as,cardiovascular disease [18], hyperuricaemia, uric acid stones [19], gout and Leseh-Nyhan syndrome [20]. Thus accurate determination of UA concentration is of great importance. Recently, electrochemical sensors have attracted much attention
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due to their advantages of simplicity, cheapness, fast analysis along with high sensitivity and selectivity [21]. The oxidation potential of DAand UA are very close such that, the bare electrode often suffers from fouling effects. The chemically modified electrodes have the ability to detect both DA and UA selectively [22,23]. The electropolymer film coated electrodes are playing an important role in sensor field. Ongera et al. studied the simultaneous determination of dopamine in presence of ascorbic acid at electropolymer modifiedcarbon paste electrode [3,4,21]. Gabriela Broncova et al. used poly (neutral red) modified electrode for determination of citrate in soft drinks [24]. M. Pandurangachar et al. prepared poly (patton’s and reeder’s) film coated carbon paste electrode for simultaneous detection of dopamine [7]. Sarah M. Kirwan studied the electrochemical properties of AA and H2O2 at Poly (o-phenylenediamine) filmmodified Platinum-iridium electrodes alloy wires [25]. In the present work, poly (EBT) film coated graphite pencil electrode is used for the selective detection of DA in the presence of UA. The electrochemical study of EBT was done by our research group [26]. Many electrochemical experiments have been done by electropolymerizing the EBT indicator and discussing their voltamAJAC

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