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-Adsorption Transition (LC PEAT) called also liquid chromatography under critical conditions of adsorption or liquid chromatography at the critical point of adsorption is a new and rapidly developing technique that - in combination with some other LC separation procedures - allows separation 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 elucidated and the nomenclature of some terms connected with the technique is proposed. The most important experimental procedures as eluent and column Packing selection are described in detail. The weakpoints of method are discussed in terms of the sensitivity of results towards minute eluent composition, temperature and pressure changes, as well as towards both chemical and physical structure of separated macromolecules and column packing used. The peak broadening, skewing and splitting that often accompany the LC FEAT experiments are also outlined. Above - mentioned, so far mostly overlooked problems may lead to limited repeatability of results and to low sample recovery, especially at higher polymer molar mass values, thus causing queries concerning the broader applicability and experimental feasibility of method. On the other hand these problems an also be regarded as a challenge to both theoreticians and experimentalists who can substantially contribute to the improvement of this powerful method - and thus to its widespread application.