Many approaches have been proposed for sample deoxygenation to bypass the adverse effect of O2 . Vacuum degassing and inert gas purging are practical in a lab environment but incompatible with point-of-use applications. Alternatively, reducing agents, such as ascorbic acid , sodium thiosulfate and sodium sulfite in the presence of a catalyst , can be used for the removal of O2. However, their intrinsic electroactivity, or the electroactivity of the required catalyst, often introduce additional interferences. Moreover, such chemical methods are often insufficiently fast for oxidase-based biosensors where the presence of O2 leads to a competing electron transfer process even before an electrical potential is applied.