Selective Determination of Uric Acid in Presence of Ascorbic Acid and Dopamine at Neutral pH Using Exfoliated Graphite Electrodes

Ramesh, P. J.; Sampath, S. R.

doi:10.1002/elan.200302890

Cited by 72 publications

(27 citation statements)

References 27 publications

(29 reference statements)

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“…Therefore it is essential to develop a simple and rapid method for their determination in routine analysis. Among many methods for determination of UA in biological samples, voltammetric method has shown to be a powerful tool [9,10]. Recently, edge plane pyrolytic graphite electrodes [11], Ir-modified carbon working electrode with immobilizing uricase [12], hexacyanoferrate lanthanum film modified electrode [13], composite film of polyaniline nanonetworks/p-aminobenzene sulfonic acid modified GCE [14] and mesoporous SiO 2 -modified carbon paste electrodes [15] have been applied for the determination of UA.…”

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confidence: 99%

Selective Detection of Uric Acid in the Presence of Ascorbic Acid and Dopamine Using Polymerized Luminol Film Modified Glassy Carbon Electrode

2009

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Electrochemically polymerized luminol film on a glassy carbon electrode (GCE) surface has been used as a sensor for selective detection of uric acid (UA) in the presence of ascorbic acid (AA) and dopamine (DA). Cyclic voltammetry was used to evaluate the electrochemical properties of the poly(luminol) film modified electrode. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) have been used for surface characterizations. The bare GCE failed to distinguish the oxidation peaks of AA, DA and UA in phosphate buffer solution (pH 7.0), while the poly(luminol) modified electrode could separate them efficiently. In differential pulse voltammetric (DPV) measurements, the modified GCE could separate AA and DA signals from UA, allowing the selective determination of UA. Using DPV, the linear range (3.0 Â 10 À5 to 1.0 Â 10 À3 M) and the detection limit (2.0 Â 10 À6 M) were estimated for measurement of UA in physiological condition. The applicability of the prepared electrode was demonstrated by measuring UA in human urine samples. Uric acid (UA) is the ultimate catabolite of purine metabolism in humans and higher primates. It is a weak organic acid that under physiologic conditions exists mainly as a monosodium salt. At a pH less than 5.75, as may occur in the urine, the predominant form is nonionized UA. The solubility of monosodium urate is about 18 times greater than UA in aqueous solutions. This solubility difference provides the therapeutic rationale for alkalinization of the urine pH to greater than 6.0 in patients forming UA stones. UA levels are influenced by age and sex. Many additional factors, including exercise, diet, drugs, and state of hydration, may result in transient fluctuations of UA levels. Extreme, abnormal levels of UA in body fluids will lead to some diseases. It is for this reason, that simple and rapid detection methods are required [1 -3].Detection of biological molecules using chemically modified electrodes is more attractive strategy since electrochemical sensors combines the specificity of biological or chemical recognition layers with the inherent advantages (sensitivity, speed, miniaturization, linearity) of electrochemical transduction [4 -6]. Polymer modified electrodes (PMEs) are received considerable attention among the researchers for sensing applications. Electropolymerization is a good approach to prepare PMEs as adjusting electrochemical parameters can control film thickness, permeation and charge transport characteristics [6 -8].Dopamine (DA), UA and ascorbic acid (AA) usually coexist in physiological samples and these molecules have a same oxidation potential on the unmodified solid electrodes. Therefore it is essential to develop a simple and rapid method for their determination in routine analysis. Among many methods for determination of UA in biological samples, voltammetric method has shown to be a powerful tool [9,10]. Recently, edge plane pyrolytic graphite electrodes [11], Ir-modified carbon working electrode with immobilizing uricase [12], hexacyanofe...

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confidence: 99%

Selective Detection of Uric Acid in the Presence of Ascorbic Acid and Dopamine Using Polymerized Luminol Film Modified Glassy Carbon Electrode

2009

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“…Thus, the cleanliness of the electrode after determination of DA is obviously important for reproducible usage. The anodic peak current of UAwas also a linear function of the scan rate over the range of 10 -200 mV/s (i pa ¼ 1.90 þ 0.099 V (R ¼ 0.9991), in agreement with the UA adsorption on RNA [22,37,38]. Although the mechanism of this strong adsorption of DA on the RNA film is not clearly known, they may bind each other mainly through the base interactions (such as hydrogen bonds and base stacking) and the electrostatic attraction between DA cation and multiple negative charges of the phosphate backbone, however the later may only play a minor role.…”

Section: Scan Rate Effectmentioning

confidence: 88%

RNA Modified Electrodes for Simultaneous Determination of Dopamine and Uric Acid in the Presence of High Amounts of Ascorbic Acid

Kang

Lin

2006

Electroanalysis

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A promising electrochemical biosensor was fabricated by electrochemical grafting of ribonucleic acid (RNA) at 1.8 V (vs. SCE) on glassy carbon electrode (GCE) (denoted as RNA/GCE), for simultaneous detection of dopamine (DA) and uric acid (UA) with coexistence of excess amount of ascorbic acid (AA). The electrode was characterized by Xray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The RNA modified layer on GCE exhibited superior catalytic ability and anionic exclusive ability in comparison with the DNA modified electrode. Three separated anodic DPV peaks were obtained at 0.312, 0.168 and À 0.016 V for UA, DA and AA, respectively, at the RNA/GCE in pH 7.0 PBS. In the presence of 2.0 mM AA, a linear range of 0.37 to 36 mM with a detection limit of 0.2 mM for DA, and in the range of 0.74 to 73 mM with a detection limit of 0.36 mM for UA were obtained. The co-existence of 5000 fold AA did not interfere with the detection of DA or UA. The modified electrode shows excellent selectivity, good sensitivity and good stability.

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“…A major obstacle in monitoring DA and UA using electrochemical technique is the influence from the co-existence of large amount of AA, since AA can also be oxidized with large overpotentials in the result of current overlapping at bare electrodes. Recently, various chemical modification of electrode surface has been used to overcome this problem by either reducing the overpotential of AA oxidation or preventing the approach of AA anions to the electrode surface [27][28][29][30][31][32][33][34][35][36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

DNA/Poly(p-aminobenzensulfonic acid) composite bi-layer modified glassy carbon electrode for determination of dopamine and uric acid under coexistence of ascorbic acid

Lin

Kang

2007

Bioelectrochemistry

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Selective Determination of Uric Acid in Presence of Ascorbic Acid and Dopamine at Neutral pH Using Exfoliated Graphite Electrodes

Cited by 72 publications

References 27 publications

Selective Detection of Uric Acid in the Presence of Ascorbic Acid and Dopamine Using Polymerized Luminol Film Modified Glassy Carbon Electrode

Selective Detection of Uric Acid in the Presence of Ascorbic Acid and Dopamine Using Polymerized Luminol Film Modified Glassy Carbon Electrode

RNA Modified Electrodes for Simultaneous Determination of Dopamine and Uric Acid in the Presence of High Amounts of Ascorbic Acid

DNA/Poly(p-aminobenzensulfonic acid) composite bi-layer modified glassy carbon electrode for determination of dopamine and uric acid under coexistence of ascorbic acid

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