Abstract
An amperometric alcohol-sensing electrode was prepared by immobilizing alcohol oxidase (AOx) in a polyion complex membrane. Three kinds of aqueous solutions (poly(4-styrenesulfonate)-, AOx- and poly-L-lysine-containing solutions) were successively placed on the surface of a glassy carbon electrode and the electrode was allowed to dry. The anodic current (at 1V vs. Ag/AgCl) of the enzyme electrode increased immediately after the addition of alcohols (e.g., ethanol), and reached a steady state within 5s. A linear response to ethanol was observed up to 0.4mM with a detection limit of 0.5μM. The polyion complex membrane showed permselectivity based on the solute size with a molecule weight cut-off of ca. 100, which was very effective in suppressing the electrochemical interference by L-ascorbic acid and uric acid. The enzyme electrode was applied to the determination of ethanol in alcoholic drinks and soy sources. The electrode could be used for two weeks.
