LIQUID-CHROMATOGRAPHY OF MACROMOLECULES AT THE POINT OF EXCLUSION-ADSORPTION TRANSITION - PRINCIPLE, EXPERIMENTAL PROCEDURES AND QUERIES CONCERNING FEASIBILITY OF METHOD

Liquid chromatography of macromolecules at the Point of Exclusion-Adso rption Transition (LC PEAT) called also liquid chromatography under cr itical conditions of adsorption or liquid chromatography at the critic al point of adsorption is a new and rapidly developing technique that - in combination with some other LC separation procedures - allows sep aration and molecular characterization of many complex polymer systems as polymer blends, interpolymers or functionalized oligomers. In this critical discussion review, tile principles of LC FEAT are briefly el ucidated and the nomenclature of some terms connected with the techniq ue is proposed. The most important experimental procedures as eluent a nd column Packing selection are described in detail. The weakpoints of method are discussed in terms of the sensitivity of results towards m inute eluent composition, temperature and pressure changes, as well as towards both chemical and physical structure of separated macromolecu les and column packing used. The peak broadening, skewing and splittin g that often accompany the LC FEAT experiments are also outlined. Abov e - mentioned, so far mostly overlooked problems may lead to limited r epeatability of results and to low sample recovery, especially at high er polymer molar mass values, thus causing queries concerning the broa der applicability and experimental feasibility of method. On the other hand these problems an also be regarded as a challenge to both theore ticians and experimentalists who can substantially contribute to the i mprovement of this powerful method - and thus to its widespread applic ation.