Far-UV CD spectra were recorded from a synthetic beta-sheet forming peptide (LKWK(LK)(8)), adsorbed onto several aqueous-quartz interfaces contained in a specially constructed cell. These hydrophilic quartz interfaces could be made hydrophobic by chemical modification with C18 alkyl chains. The hydrophobic quartz provides a model system for oil-in-water emulsions and cell membranes, The peptide had multiconformational properties. beta-sheet structure was induced into the molecule with increasing NaCl concentrations, whereas 2,2,2-trifluoroethanol induced alpha-helix. Radiolabeling of the peptide for surface concentration measurements was also found to introduce considerable beta-sheet structure, The characterization of the adsorbed spectra was partly achieved using far-UV CD spectra of beta-peptide adsorbed onto hydrophilic colloidal silica particles, which eliminated orientation effects.