Chromatographic Evaluation of Resolution and Secondary Mechanisms of Pure and Mixed Sets of SEC Columns: TSK-Gel H_HR and TSK-Gel H_XL

Abstract

Size exclusion chromatographic (SEC) evaluation of secondary mechanisms and column specific resolution, of five solvent/polymer systems in four sets of pure and mixed organic columns packings based on polystyrene/divinylbenzene copolymer, TSK-Gel H_HR and TSK-Gel H_XL, has been carried out. The combination of columns employed has been: (i) three H_HR columns (set A); (ii) two H_HR and one H_XL column (set B); (iii) one H_HR and two H_XL columns (set C) and (iv) three H_XL columns (set D). Both packings offer similar characteristics (pore size, particle size, efficiency) but some differences have been found when eluting the same systems in different combination of both of them. Values of the chromatographic partition coefficient, K _p , of the volume fraction of the network in the swollen state, φ₃, and the concentration effect on the retention volume have been related. It can be concluded that the higher the φ₃, the higher the crosslinking degree and K _p , and the higher the concentration effect on the retention volume for a given solvent/polymer system. We also observe that, in general, a decrease of K _p comes along with an increase of specific resolution, R _S , and that the sets of mixed columns show lower secondary effects different from pure size exclusion (lower K _p ) and higher R _S than the two sets of pure H_HR or H_XL columns.