Amperometric biosensor for glutamate using prussian blue-based "artificial peroxidase" as a transducer for hydrogen peroxide.

The specially deposited Prussian Blue denoted as "artificial peroxidase" was used as a transducer for hydrogen peroxide. The electrocatalyst was stable, highly active, and selective to hydrogen peroxide reduction in the presence of oxygen, which allowed sensing of H2O2 around 0.0 V (Ag/AgCl). Glutamate oxidase was immobilized on the surface of the Prussian Blue-modified electrode in a Nafion layer using a nonaqueous enzymology approach. The calibration range for glutamate in flow injection system was 1 x 10(-7)-1 x 10(-4) M. The lowest concentration of glutamate detected (1 x 10(-7) M) and the highest sensitivity in the linear range of 0.21 A M-1 cm-2 were achieved. The influence of reductants was practically avoided using the low potential of an indicator electrode (0.0 V Ag/AgCl). The attractive performance characteristics of the glutamate biosensor illustrate the advantages of Prussian Blue-based "artificial peroxidase" as transducer for hydrogen peroxide detection.