Development and Characterization of Cobalt Hexacyanoferrate Modified Carbon Electrodes for Electrochemical Enzyme Biosensors

Abstract

Carbon film electrodes have been modified with films of cobalt hexacyanoferrate by potential cycling from solutions containing cobalt and hexacyanoferrate ions. The voltammetric characteristics of the films have been investigated in different electrolyte solutions and the properties related to insertion reactions within the crystal structure. The application of these modified electrodes as redox mediators in enzyme biosensors has been investigated using the mediated detection of hydrogen peroxide, demonstrated by the determination of glucose using glucose oxidase. Excellent detection limits in the micromolar region have been attained and the principle of measurement in real samples demonstrated by that of glucose in sweet wine.

Keywords:

• Carbon film
• Cobalt hexacyanoferrate
• Enzyme electrode
• Glucose
• Glucose oxidase

Acknowledgments

Financial support from Fundação para a Ciência e Tecnologia (FCT), ICEMS (Research Unit 103), European Projects QLK3‐2000‐01311 and HPRN‐CT‐2002‐00186 and the European Union Socrates program are gratefully acknowledged. Prof. H. D. Liess is thanked for the gift of the electrical resistors.