Oxides of platinum metal group as potential catalysts in carbonaceous amperometric biosensors based on oxidases

Oxides of four platinum metals (PdO, OsO2, IrO2, PtO2) were incorporated into carbonaceous materials such as carbon paste or carbon ink to study their catalytic properties towards oxidation or reduction of hydrogen peroxide, which is known as a product of biocatalytic reactions in which enzymes of the oxidases participate. In the second step, glucose oxidase – the typical representative of the group – was immobilized in a Nafion film onto the surface of screen-printed carbon electrodes and investigated for its ability to serve as a detector of glucose in flow injection analysis. From all the metal oxides selected, IrO2 was found the best, because it was capable to operate at low applied potentials (around −0.2 V) at which the undesirable effects of common interfering species (both ascorbic and uric acids) were significantly eliminated.