ABSTRACT
The direct measurement of protein adsorption at liquid interfaces is a quite complicated technical problem. The most common methods here are radiotracer technique, neutron reflection and interfacial ellipsometry. Advantages and drawbacks of these methods were extensively discussed in [1-7]. For example, to apply the ellipsometry, one has to assume a model for the surface layer structure, in particular the refractive index profile of the protein solution adjacent to the interface, which restricts the applicability of the method. Extensive experimental studies of surfactant adsorption layers at liquid interfaces were performed by neutron reflection and radiotracer techniques [8-11]. Additional optical methods, such second harmonic generation, sum frequency spectroscopy, infrared and Raman spectroscopy, X-ray reflection are thoroughly analysed and widely referenced in [10, 11]. Despite some deficiencies and model assumptions, these methods have considerably improved our understanding of the adsorption mechanism at liquid-fluid interfaces.
