1995 Volume 11 Issue 2 Pages 251-256
Amperometric L-glutamic acid sensors were fabricated by depositing L-glutamate oxidase (GLOD) and horseradish peroxidase (HRP) on the tin oxide surface by means of either encapsulation into electropolymerized pyrrole or sequential chemical modification via surface hydroxyl groups. After optimization for the mixing ratio of the two enzymes during polypyrrole (PPy) formation and for the thickness of the PPy film, the GLOD/HRP/PPy electrode gave a nearly linear response to L-glutamic acid in the concentration range of 10-7 to 10-4M, with a response time of about 1min. The GLOD/HRP bilayer-modified electrode showed a sensitivity comparable to that of the PPy-encapsulated bienzyme electrode. Both type of electrodes exhibited excellent substrate specificity. The pH dependence and lifetime of the sensor response are also given.
