Carbon fibre and carbon disk microelectrodes have been used in both the detection of oxidizable compounds (Gonon, et al., 1978; Cahill and Wightman, 1995) and extracellular single-unit recording (Armstrong-James and Millar, 1979). WPI's ultra-sensitive and low-noise carbon fibre (CF) and carbon-disk (CD) electrodes can be applied, with our Micro-C Potentiostat or similar instruments, in the electrochemical detection of catecholamines (epinephrine, norepinephrine and dopamine), indolamines (serotonin, 5-HT or melatonin), ascorbic acid, Fe (II), and other oxidizable compounds.

CF electrodes (diameter of 10 or 30 µm) respond with an excellent linearity to the oxidizable compounds (Fig. 1) and can detect the compounds as low as 0.2 nM. While the shorter length (25-100 µm) of CF electrodes are suitable for in vivo amperometric and voltammetric measurements, the longer CF electrodes provide higher sensitivity and are especially useful for the in vitro studies (amperometric or differential pulse voltammetry). When used with the Micro-C Potentiostat, these CF electrodes can be activated and renewed in sensitivity for multiple use. The selective detection of catecholamines can be achieved with our Nafion-coated CF electrodes. For selective detection of 5-HT and ascorbic acid, please contact WPI for more information.

Fig. 2 Extracellular recording using a carbon disk electrode (CD-30) in CA1 region of the hippocampus in an anesthetized rat shows ultra-low noise ( <5 µV ). Courtesy: Dr. Carolyn Harley of Memorial University, Newfoundland, Canada.

Because of their ultra-low noise performance ( < 5 µV ) (Fig. 2), the innovative CD electrodes are extremely suitable for in vivo or in vitro extracellular recording especially where the action potentials are recorded from small interneurons which may be difficult to isolate with other methods. The CD electrodes features an excellent plastic insulation which has a better dielectric property than glass. They can withstand strong acid or base without leakage. The bevelled CD electrodes can also be used for the direct detection of neurotransmitter release. They provide excellent spatial resolution in such applications since they can be placed right above the cell of interest for localized recording. The strong yet flexible disk tip design makes our CD electrodes durable and reusable.

Micro C can be used successfully with your own microelectrode or one of WPI's microdisc (10 microns) or carbon fibre (8 or 30 microns) microelectrodes.

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Cahill, P.S., and Whightman, R.M., Anal. Chem., 67, 2599-2605 (1995). 
Gonon, F., et al., Hebd Seances Acad. Sci. Ser. 286, 1203 (1978). 
Armstrong-James, M., and Millar, J., J. Neurosci. Methods, 1, 279 (1979).