Multivariate data analysis for enhanced interpretation of electrochemical impedance spectra of gramicidin-ion interactions in phospholipid monolayers
by Lindholm-Sethson, Britta; Geladi, Paul; Koeppe II, R. Erdman; Jonsson, Oskar; Nilsson, David; Nelson, Andrew
This article describes a multifrequency electrochemical impedance study of phospholipid monolayers on a mercury drop electrode in solutions containing electrolytes and gramicidin derivatives: gramicidin A (gA), gramicidin-BOC (g-BOC), and desformylgramicidin (g-des). The impedance spectra have been studied individually (univariate approach) and also transformed using a multivariate data reduction method (multivariate approach). It was shown that the two approaches are complementary. Thus the formation of K+-conducting channels is observed in gA only, and these channels can be distinguished from an interaction of all gramicidin derivatives with Mg2+. An unknown peptide interaction in the monolayer was observed on a slow time scale.
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