In this study, we report the fabrication of physically small
fouling-resistant hydrogenated carbon electrodes (typically 1 -
2 μm tip diameter, 8 mm axial length) and their application to
detect the neurotransmitter dopamine in vivo. Dopamine is an
important neurotransmitter in the brain. A loss of dopamine
containing neurons or its transmission has been associated with
a number of illnesses and conditions including Parkinson's
disease, schizophrenia, motivational habit, reward mechanisms
and the regulation of motor functions and in the function of the
central nervous, hormonal and cardiovascular systems. It is
therefore of interest to measure dopamine in the extracellular
fluid in animals in order to monitor neurotransmission processes
and correlate neurochemistry with behaviour. However, a common
problem encountered in the voltametric determination of dopamine
in vivo is interference from ascorbic acid, which is not only
present in much higher concentrations (125 - 420 μM compared to
0.2 - 2.0 μM for dopami