Amperometric Biosensor for Glutamate Using Prussian Blue-Based “Artificial Peroxidase” as a Transducer for Hydrogen Peroxide

Abstract

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 × 10^-7−1 × 10^-4 M. The lowest concentration of glutamate detected (1 × 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.