1,1′-Dimethylferrocene Mediated L-Glutamate Electrodes Modified With Electropolymerized 1,3-Diaminobenzene Film

Abstract

A mediated L-glutamate biosensor was constructed by incorporating 1,1′-dimethylferrocene in electropolymerized 1,3-diaminobenzene and immobilizing L-glutamate oxidase on the electropolymerized film. Stabilizers (1% DEAE-dextran, 1% MgCl₂ and 10% sucrose) were added to the immobilized enzyme to improve the long-term storage stability. The electrode responded linearly to L-glutamate concentration between 0.1 and 2.0 mM and the response of the electrode did not interfere with electroactive species and oxygen. The useful lifetime of the sensor was at least 3 weeks. When stored in dry form at 28°C, the sensor with stabilizers was stable at least 6 months. The electrode was applied to determine L-glutamate in fermentation broth samples. Good correlations were achieved between results obtained with the sensor and by enzymatic analysis using glutamate dehydrogenase.

Key Words:

• Biosensor
• 1,1′-Dimethylferrocene mediated sensor
• 1,3-Diaminobenzene
• Electropolymerized film
• Stabilizers