Single-walled carbon nanotubes on tungsten wires; a new class of microelectrochemical sensors

This paper reports the fabrication and the outstanding performance characteristics of novel microelectrodes consisting of tungsten (W) wires coated with homogeneous layers of single-walled C nanotubes (SWNT). A series of studies using cyclic voltammetry indicate that the SWNT-modified W electrodes possess interesting electrochemical features. In fact, they are able to catalyse electron transfer reactions involving a series of inorganic and biological molecules. These electrodes are characterized by a fast electron transfer, a wide working potential window, and a low background current. Moreover they demonstrate excellent reproducibility, good stability in various chemical media, and very high sensitivity towards a series of inorganic and organic compounds. The SWNT modified microelectrodes have been tested for the capacity to electrochemically detect ferrocene monocarboxylic acid and potassium hexacyanoferrate as well of a series of interesting biological molecules which include catechol, caffeic acid, DOPAC, ascorbic acid, L-tyrosine, acetaminophen, guanine, uric acid, and the neurotransmitters dopamine, epinephrine, and serotonin (5-HT) hydrochloride. The advantages of the SWNT-modified W electrodes are illustrated by comparing their analytical performance with that of conventional electrodes.