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.