STUDY OF ION TRANSFER ACROSS PHOSPHOLIPID MONOLAYERS ADSORBED AT MICROPIPETTE ITIES

The transfer of tetraethylammonium cations across phospholipid monolay ers deposited at a micropipette ITIES (interface between two immiscibl e electrolyte solutions) was studied using short potential step techni ques. The observed current transients consisted of a capacitive and a faradaic current component, which were separated using a non-linear fi t to a model function. Fits were very good. From the capacitive compon ent, the surface coverage of lipids was calculated by applying a simpl e model for the monolayer configuration. It appeared that the coverage varied between 80 and 99%. The rate of ion transfer was increased sli ghtly after the lipid addition, but no significant variations between different lipids were found. The transfer mechanism is discussed brief ly.