Fast cyclic voltammetry: measurement of dopamine in the presence of its biological precursors and metabolites

Abstract

In vivo voltammetry is widely used to measure dopamine concentrations in the extracellular fluid of the animal brain. However, a potentially serious analytical problem is the presence in vivo of other compounds that may interfere with electrochemical measurements of dopamine. The present study examined the effects of physiological concentrations of various biological precursors and metabolites of dopamine on the detection of the parent compound with fast cyclic voltammetry at carbon fibre microelectrodes. No compound affected the potentials of the oxidation or reduction peaks for dopamine. Homovanillic acid caused an apparent increase in the sensitivity of the electrodes to dopamine while ascorbic acid decreased the height of the reduction peak. Effects were small and we conclude that physiological levels of precursors and metabolites do not constitute a hazard to the voltammetric detection of dopamine in vivo using fast cyclic voltammetry.