INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
artículos
Título:
Simultaneous determination of uric acid and ascorbic acid on a glassy carbon electrode modified with multi-wall carbon nanotube-polylisine film
Autor/es:
MARCELA C. RODRIGUEZ; JOSé SANDOVAL; LAURA GALICIA; SILVIA GUTIERREZ; GUSTAVO A. RIVAS
Revista:
SENSORS AND ACTUATORS B-CHEMICAL
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2008
ISSN:
0925-4005
Resumen:
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 sensitivities were (9.8 ± 0.2) x 104 ìAM-1 (r= 0.994), and (10.7 ± 0.2) x 104 ìAM-1 (r = 0.994) in the presence and absence of 1.0 mM ascorbic acid, respectively. The detection limit for uric acid in the mixture was 1.7 x 10-5 M. In the case of DPV-adsorptive-stripping determination, an important enhancement in sensitivity was obtained, allowing the detection of 2.2 x 10-6 M uric acid. The sensor was successfully used for the quantification of uric acid in serum samples.