The exact stoichiometry of these steps is dependent on the medium. The large background current accrued from this stepwise oxygen reduction interferes with the measurement of many reducible analytes. In addition, the products of the oxygen reduction may affect the electrochemical process under investigation. A variety of methods have thus been used for the removal of dissolved oxygen. The most common method has been purging with an inert gas (usually purified nitrogen) for 4-8 min prior to recording of the voltammogram.