Introduction: The modern analytical demand requires fast, inexpensive and easy convey
methods, therefore several sensor and biosensor methods have been developed.
Methods: In this context two different enzyme electrodes for the determination of ethanol were assembled
by the authors, immobilizing alcohol oxidase or catalase in a k-Carrageenan gel layer overlapping
an amperometric gaseous diffusion Clark type oxygen electrode. The two enzyme sensors used different
formats, as the alcohol oxidase biosensor was a conventional direct enzyme sensor, while the catalase
biosensor was based on the antagonism of a different substrate for the same enzyme. The response
of the two biosensors toward standard solution of ethanol was recorded, compared and discussed.
Conclusion: Finally, by using the fabricated biosensors, ethanol concentrations of several pharmaceutical
formulations were determined and the results, obtained with two enzyme electrodes, were compared.
The precision of the two methods on pharmaceutical samples was comparable and recovery tests
on real matrices were satisfactory for both the biosensors, however in the applications to pharmaceutical
formulations the alcohol oxidase biosensor seems to be more reliable.