We have immobilized a series of cyclic and acyclic Fc-peptides on the gold microelectrode in order to investigate peptide interactions with alkaline metals. The solutions used for alkaline metal-peptide film interaction studies were: 50 mM HClO4 and 25 mM XClO4, where X = Li, Na, K, Rb, and Cs. Our study indicates that the formal potential is influenced with shifts of up to 100 mV. The peak separation Delta E values are also influenced by the presence of the alkaline metal cations. Changes up to 90 mV were observed. The observed changes were attributed to the variations of orientation of ferrocene on the gold surface. (C) 2007 Elsevier Ltd. All rights reserved.