New bimetallic porphyrin film An electrocatalytic transducer for hydrogen peroxide reduction, applicable to first-generation oxidase-based biosensors

摘要

A bimetallic porphyrin film was studied as electrode modifier with catalytic activity for molecular oxygen reduction and hydrogen peroxide reduction. Molecular oxygen reduction is catalyzed by both polyFePPIX or polyCuPPIX. Peroxidase activity at -200 mV versus Ag/AgCl is only performed by polyFePPIX in absence of oxidative agents, and the deposit polyCuPPIX is required to perform peroxidase activity in the presence of oxygen. Copper substitution by other metals in the porphyrin was not effective. It has been found that metallo-porphyrin immobilization order acquire particular relevance. However, the mass of porphyrin deposit is always 1.5-1.6 μg of polyFePPIX and 7.3-9.1 μg of polyCuPPIX, indicating that polymer growth rate is not affected by immobilization order. polyCuPPIX deposited on polyFePPIX preserves catalytic properties over a wide pH range, and acts as a molecular sieve. The use of this bimetallic electrode in a first-generation oxidase biosensors is discussed.