Highly sensitive determination of uric acid in the presence of ascorbic acid at glassy carbon electrodes modified with carbon nanotubes dispersed in polylysine

MARCELA C. RODRIGUEZ, ; J. SANDOVAL; LAURA GALICIA; G. A. RIVAS

ELSEVIER SCIENCE SA

Año: 2008 vol. 134 p. 559 - 559

font size="3"> This article reports the highly selective and sensitive uric acid quantification in the presence of ascorbic acid using glassy carbon electrodes (GCE) modified with multi-wall carbon nanotubes (MWCNT) dispersed in polylysine (Plys) (GCE/MWCNT-Plys). The electrocatalytic activity of MWCNT deposited on glassy carbon electrodes has allowed an important decrease in the overvoltages for ascorbic acid oxidation (440 mV), making possible the clear definition of the oxidation processes of ascorbic acid and uric acid. Two protocols for uric acid quantification are described, the direct Differential Pulse Voltammetry (DPV) detection, and the DPV-Adsorptive Stripping detection with medium exchange. For the direct determination of uric acid, the sensitivities were (9.8 ± 0.2) x 104 ìAM-1 (r2= 0.994), and (10.7 ± 0.2) x 104