Separation of parent homopolymers from diblock copolymers by liquid chromatography under limiting conditions of desorption 3. Role of column packing

The novel separation method, liquid chromatography under limiting conditions of desorption, LC LCD enables rapid one-step discrimination of both parent homopolymers from diblock copolymers. The low-molecular admixtures/impurities can be base-line separated, as well. The general rules for selection of the LC LCD columns are reviewed. Bare silica gel column packings are discussed in detail. Selected examples of separation are presented. They demonstrate that the principle of LC LCD separation is not affected by the particle size and initial purity of bare silica gel column packing nor by its effective pore diameter and volume. However, appropriate choice of the packing pore size facilitates base-line separation of particular sample constituents. Important may be the column history; columns saturated with previously adsorbed polymers may lose their performance. Up to a certain limit, success of the LC LCD separation does not depend on the column efficiency and reasonable results can be obtained even with the columns packed with rather big particles. This indicates possibility of the large-scale preparative applications and feasibility of the high-speed LC LCD separations.