Hartvig, RuneAgudelo, MendezAlejandro, Manuelvan de Weert, MarcoJorgensen, LeneOstergaard, JesperGirault, HubertJensen, Henrik2011-05-112011-05-112011-05-11201010.1021/ac101528rhttps://infoscience.epfl.ch/handle/20.500.14299/67277WOS:000281710900025The interaction between an intact protein and two lipophilic ions at an oil-water interface has been investigated using cyclic voltammetry, impedance based techniques and a newly developed method in which the biphasic oil-water system is analyzed by biphasic electrospray ionization mass spectrometry (BESI-MS), using a dualchannel electrospray emitter. It is found that the protein forms interfacial complexes with the lipophilic ions and that it specifically requires the presence of the oil-water interface to be formed under the experimental conditions. Furthermore, impedance based techniques and BESI-MS with a common ion to polarize the interface indicated that the Galvani potential difference across the oil-water interface significantly influences the interfacial complexation degree. The ability to investigate protein-ligand complexes formed at polarized liquid-liquid interfaces is thus a new analytical method for assessing potential dependent interfacial complexation using a structure elucidating detection principle.Ionization Mass-SpectrometryLiquid-Liquid InterfacesRedox-Inactive ProteinsElectrospray-IonizationLiquid/Liquid InterfacesElectrochemical-BehaviorElectrolyte-SolutionsGibbs EnergiesSolid-SurfacesEsi-Mstext::journal::journal article::research article