Nanostructured Carbon Fiber Disk Electrodes for Sensitive Determinations of Adenosine and Uric Acid

Nanostructured carbon fiber microdisk electrodes were prepared by a combination of mechanical polishing and electrolytic treatment, where the latter involved moderate oxidation of the surface, followed by a reduction. A high density of surface defects contributed to a high capacitance of the nanostr...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2000-04, Vol.72 (7), p.1576-1584
Main Authors: Brajter-Toth, Anna, El-Nour, Kholoud Abou, Cavalheiro, Eder T, Bravo, Roberto
Format: Article
Language:English
Subjects:
Acids
Analytical chemistry
Analytical, structural and metabolic biochemistry
Biological and medical sciences
Carbon
Chemistry
Electrochemical methods
Exact sciences and technology
Fundamental and applied biological sciences. Psychology
Intermediary metabolites. Miscellaneous
Other biological molecules
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Summary:Nanostructured carbon fiber microdisk electrodes were prepared by a combination of mechanical polishing and electrolytic treatment, where the latter involved moderate oxidation of the surface, followed by a reduction. A high density of surface defects contributed to a high capacitance of the nanostructured electrodes. Facilitated proton transfer was observed at the nanostructured surface and was associated with cation-exchanged oxide defects. The nanostructured surfaces intercalated uric acid and adenosine and engaged in fast electron/proton transfer in the oxidation of both analytes. As a result, electrolytic treatment followed by fast-scan voltammetry determinations led to a sensitive response to both analytes in physiological buffers. The nanostructured electrodes showed remarkable stability and could be easily regenerated and reused. With long use, electrode activity decreased. Kinetic discrimination of the surface-mediated reaction of ascorbate was achieved at high scan rates.
ISSN:0003-2700
1520-6882
DOI:10.1021/ac9906680