Simultaneous determination of uric acid and ascorbic acid on a glassy carbon electrode modified with multi-wall carbon nanotube-polylisine film

MARCELA C. RODRIGUEZ; JOSÉ SANDOVAL; LAURA GALICIA; SILVIA GUTIERREZ; GUSTAVO A. RIVAS

Elsevier

Lugar: Amsterdam; Año: 2008 p. 559 - 559

p style="TEXT-ALIGN: justify; MARGIN: 0cm 0cm 0pt; mso-layout-grid-align: none" class="MsoNormal">This article reports the highly selective and sensitive uric acid quantification in the presence of ascorbic acid using glassy carbon electrodes (GCE) modified with a dispersion of multi-wall carbon nanotubes (MWCNT) in polylysine (Plys) (GCE/MWCNT-Plys). The electrocatalytic activity of MWCNT deposited on the glassy carbon electrode has allowed an important decrease in the overvoltages for ascorbic acid oxidation (440 mV), making possible the clear definition of the two oxidation processes. Two protocols for uric acid quantification are described, the direct detection by Differential Pulse Voltammetry (DPV), and the detection previous a preconcentration step with medium exchange (DPV-Adsorptive Stripping). For the direct determination of uric acid, the sensitivit