Effect of fluorescence labelling on the properties of protein adsorption layers at the air/water interface

Fluorescence dyes Rhodamine and Fluorescein do not influence the adsorption layer properties of labelled β-lactoglobulin when used at sufficiently low concentration. However, due to interference of light absorption and emission by the dye with the registration of ellipsometric signals in surface ellipsometry experiments, errors can result. To avoid erroneous adsorption layer data, the laser light sources in ellipsometers should be selected such that the sensitivity peak of the photo detector is within a sufficient distance to the absorption and emission wavelengths of the dye.