The Electrochemical Properties of Co(TPP), Tetraphenylborate Modified Glassy Carbon Electrode: Application to Dopamine and Uric Acid Analysis

Abstract

We report the combination of the charge repelling property of tetraphenyl-borate (TPB) anion and the electrooxidation catalytic effect of cobalt(II) tetrakisphenylporphyrin (CoTPP) embedded in a sol gel ceramic film to develop a modified glassy carbon electrode (CoTPP-TPB-SGGCE) for the simultaneous determination of dopamine (DA) and uric acid (UA). The optimized CoTPP-TPB-SGGCE shows excellent sensitivity and selectivity for the DA and UA analysis. As high as 2000 fold acceptable tolerance of ascorbic acid (AA) for the determination of trace DA and UA is reached. In the presence of 0.10 mM AA, the linear concentration range for DA is from 6.0 Â 10 À8 to 2.5 Â 10 À5 M, and the detection limit is 2.0 Â 10 À8 M. For UA, the linear concentration range is from 1.0 Â 10 À7 to 3.5 Â 10 À5 M, and the detection limit is 7.0 Â 10 À8 M. Our study has also demonstrated that the novel CoTPP-TPB-SGGCE shows high stability and reliability. For 6.00 mM DA and UA, a total of 12 measurements were taken in one week, and the relative standard deviation is 2.05% and 2.68% respectively. No obvious shift of peak current and peak potential is observed over a three-month lifetime test. The response of the sensor is very quick and response time is approximately 1 s. Satisfactory results are also achieved when the CoTPP-TPB-SGGCEs being used to detect the DA and UA in human urine samples.

Electrochemical Oxidation of Dopamine in the Presence of Secondary Amine. An Alternative Way for Quantitative Dopamine Determination at a Gold Electrode

“…While, Zhang et al [37] have presented the cyclic voltammogram of gold electrode for 1 mM dopamine solution at pH 7.2 with anodic and cathodic peaks at E ¼ 0.46 V and 0.064 V vs. saturated Ag j AgCl electrode, respectively. Since the pK a of dopamine is 8.87 [58], below this pH value dopamine exists mainly in its protonated form and shows weak nucleophilic activity for intramolecular 1,4-Michael addition. However, in a solution of pH 7 and an adjusted dopamine concentration the amount of unprotonated dopaminoquinone is sufficient for the cyclization reaction to occur.…”

Simultaneous voltammetric detection of dopamine and uric acid at their physiological level in the presence of ascorbic acid using poly(acrylic acid)-multiwalled carbon-nanotube composite-covered glassy-carbon electrode

“…Simultaneous determination of AA and UA was also reported (Zare et al, 2005). Recently, there is intense investigation in the development of methods for the detection of DA and UA (Zen and Chen, 1997;Kang and Lin, 2006;Lin and Gong, 2006;Liu et al, 2006;Zeng et al, 2006;Salimi et al, 2006), considering the co-existence of DA and UA as well as excess of ascorbic acid in extracellular fluids. However, these methods lack of sensitivity.…”

Selective response of dopamine in the presence of ascorbic acid and uric acid at gold nanoparticles and multi-walled carbon nanotubes grafted with ethylene diamine tetraacetic acid modified electrode

“…The AuNPs and EDTA-MWCNT modified film shows high electrocatalystic activity toward DA and a couple of sharp and symmetrical redox peaks was observed as seen from Figure 3. The current response curve of the sensor was similar as that of cobalt(II) tetrakisphenylporphyrin modified film [5] toward DA.…”

“…Design and development of a simple and rapid detection method for dopamine (DA), an important neurotransmitter in mammalian central nervous system [1,2] has drawn much attention [3][4][5][6]. In real biological matrices, the concentration of DA is very low, while many coexisting substances such as ascorbic acid (AA) are in relatively high, 1000 times higher than that of DA generally.…”