Submitted to: Journal Electroanalytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 4, 2003
Publication Date: N/A
Interpretive Summary: Ionic liquids are a new, nonvolatile, environmentally friendly class of solvents that can be substituted for volatile organic solvents. One of our goals is to invent methods of transforming agricultural products to higher value products that use ionic liquids instead of more commonly used organic solvents. This study examines for the first time the behavior of an enzyme bound to an electrode in ionic liquids. These enzyme-modified electrodes could eventually be used to change vegetable oils in a specific way to make agriculturally based cosmetics, skin care products, and nutrition supplements. The fact that the enzyme could be used several times in the environmentally friendly ionic liquids results in less waste and a "greener" method of producing the desired products.
Technical Abstract: The direct electrochemical reduction of cytochrome c's Fe(III)/Fe(II) redox couple was studied in the ionic liquids (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and hexafluorophosphate. Gold electrodes modified with cyt-c adsorbed to monolayers of 11-mercaptoundecanoic acid (11-MUA) and 11-mecapto-1-undecanol (11-MU) were electrochemically inactive upon prolonged exposure to the ILs. Hydrated cyt-c modified electrodes that were initially redox active in the IL become inactive after 1 h exposure to the IL. These results suggest that the ILs strip essential water from the adsorbed cyt-c, similar to hydrophilic organic solvents, resulting in an electrochemically inactive enzyme.