IMR Press / FBL / Volume 11 / Issue 3 / DOI: 10.2741/2026

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article
A novel electrochemical biosensor for the detection of uric acid and adenine
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1 Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
Front. Biosci. (Landmark Ed) 2006, 11(3), 2976–2982; https://doi.org/10.2741/2026
Published: 1 September 2006
Abstract

A novel electrochemical biosensor for the detection of uric acid and adenine was prepared based on a gel containing multi-walled carbon nanotubes and room-temperature ionic liquid of 1-octyl-3-methylimidazolium hexafluorophosphate. The electrochemistry of uric acid and adenine was studied in this gel modified electrode. There was a significant two-way electrocatalytic activity upon both oxidation and reduction of uric acid. Similar to a bare glassy carbon electrode, uric acid undergoes a 2e,2H+ oxidation in phosphate buffer in the modified electrode. A diimine, the oxidation product of uric acid, was found to be an unstable intermediate, which was converted by a follow-up hydration reaction to an imine alcohol, with the reaction rate constant of 8.5 +/- 0.3 M-1⋅s-1 according to Nicholson's theory. Under optimum conditions, linear calibration graphs were obtained over the concentration range of 1.0×10-7 M ~ 1.0 x 10-5 M (uric acid) and 1.0×10-5 M ~ 6.0×10-4 M (adenine). Based on the signal-to-noise ratio of 3, the detection limits of the current technique was found to be as low as 9.0×10-8 M (uric acid) and 2.0×10-6 M (adenine), respectively. This novel biosensor was successfully applied for the assay of uric acid in human urine. Because of its good stability and long-term durability, such a gel modified electrode can provide a simple and easy approach for sensitive detection of uric acid and adenine.

Keywords
Carbon nanotubes
Ionic liquids
Uric acid
Adenine
Biosensor
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