Carbon Nanotubes Paste Electrodes. A New Alternative for the Development of Electrochemical Sensors.

G. A. RIVAS*, M. D. RUBIANES, M. L. PEDANO, N. F. FERREYRA, G. L. LUQUE, M.C. RODRÍGUEZ AND S. A. MISCORIA

ELECTROANALYSIS

Wiley-VCH Verlang GmbH & Co, KgaA, Weinheimv

Lugar: Las Cruces, New México, EEUU; Año: 2007

1040-0397

In this work we summarize the recent activities of our group regarding the analytical performance of a new composite material, the so-called carbon nanotubes paste electrode (CNTPE) obtained by dispersion of multi-walled carbon nanotubes in mineral oil. The electrocatalytic properties towards different redox systems, especially those involved in important enzymatic reactions are discussed. Significant shifting in the overpotentials for the oxidation and/or reduction of hydrogen peroxide, NADH, phenol, catechol, dopamine, ascorbic acid, uric acid and hydroquinone are obtained at CNTPE in comparison with the analogous graphite paste electrode (CPE). The usefulness of the electrode as a matrix for immobilizing enzymes is also demonstrated. Highly sensitive and selective glucose quantification is accomplished even without using permselective films or redox mediators. Enzymatic biosensors obtained by incorporation of lactate oxidase, polyphenol oxidase and alcohol dehydrogenase/NAD+ within the composite material have allowed the successful quantification of lactate, phenol, dopamine, catechine and ethanol. The sensitive quantification of traces of oligonucleotides and double stranded calf thymus DNA by adsorptive stripping is reported. The confined DNA layer demonstrated to be stable either in air, acetate or phosphate buffer. The advantages of incorporating copper particles for the quantification of aminoacids and albumin is also discussed.