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

Abstract

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 multiwall 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 þ within the composite material have allowed the successful quantification of lactate, phenol, dopamine, catechin 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 amino acids and albumin is also discussed.

Electroanalytical chemistry for the analysis of solids: Characterization and classification (IUPAC Technical Report)

“…A variety of carbon-based materials have been introduced recently. These include glassy carbon powder [108], acetylene black [109], template carbon or porous carbon foam [110], doped diamond [111], fullerenes [112], carbon nanofibres [113], and nanotubes [114]. The scope of CPEs has been significantly expanded by the use of ionic liquids [115] or binding agents, like phenantrene, undergoing solidification during carbon paste preparation [116].…”

Electroanalytical Applications Based on Carbon Nanotube/Prussian Blue Screen-printable Composite

“…In addition, special attention has been paid to the possibilities of carbon nanotube paste (CNTP)-based electrodes in electrochemical investigations and in modern electroanalysis. Rivas group [16][17][18][19][20][21] has reported on the advantages of CNTP electrode on the electrochemical behavior of different redox systems based on the use of CNTs dispersed in a mineral oil: dopamine, ascorbic acid, dopac and uric acid as well as hydrogen peroxide; 16 guanine, adenine and nucleic acids; 17 phenol, catechol, NADH and hydroquinone; 18 epinephrine and norepinephrine; 19 and glucose. 20 Wang et al reported the use of CNTP electrode for the oxidation of hemocysteine.…”

Carbon paste electrodes in the new millennium

“…However, because both diamond and the binder in such pastes are electric insulators, the functioning of these electrodes remains rather mysterious. In last years, intensively popularized (vi) new forms of carbon complete the list with other pastes made of fullerenes ("C-60" [62,63]), carbon nanoparticles [64], or pastelike mixtures with carbon nanofibers [65], and various types of carbon nanotubes [66]; the latter representing a new phenomenon also within the electrochemistry with carbon pastes, deserving a special attention [2].…”