Microelectrode studies of isoflurane and oxygen vapour mixtures in dimethyl sulfoxide

The electrochemical reduction of the inhalation anaesthetic agent isoflurane was investigated at a commercially available Au microelectrode (5 μm) in DMSO solvent, individually, and also as a component of a simple vapour mixture with oxygen using both traditional voltammetric and potential step chronoamperometric techniques. In a binary gas mixture with oxygen, isoflurane is shown to react with the superoxide anion radical, formed from the electro-reduction of oxygen complicating their simultaneous detection. The observed cross-interference reaction is shown to be dependent of the electrode size and the concentration of the anaesthetic agent, isoflurane. Under steady-state conditions, and using small diameter microelectrodes (5 μm) and low isoflurane concentration ([ISO]