| Abstract: | ![]()
Many liquid chromatographic (LC) separations of macromolecules are influenced or directly based on adsorption of solutes on column packing. In the case of well known size exclusion chromatography (SEC), adsorption effects are usually unwanted and therefore suppressed. Still they appear in many SEC systems and may badly affect precision of results obtained. In other LC methods applicable to high polymers, adsorption is deliberately combined with exclusion. The aim is to discriminate complex polymer systems which exhibit more than one single distribution of their molecular characteristics. The main goals of such combinations include either a controlled increase or a full suppression of separation selectivity according to one molecular characteristics. Most important so far known exclusion-adsorption compensation methods allowing to suppress dependence of LC retention volumes on polymer molar mass are reviewed. The discussion is accomplished with a presentation of newly developed full adsorption - desorption (FAD) method which can be combined with various LC procedures. A very useful combination represents the on-line FAD/SEC procedure which enables also to study adsorption and desorption phenomena in the systems solid surface - solvent - macromolecules. |
