Apparent pore size distributions of chromatography media

The use of size-exclusion chromatography for determination of pore dimensions of chromatography media is reviewed. It is noted that many researchers still use the simple but inaccurate method of treating the selectivity curve as a cumulative pore size distribution. An alternative procedure for estimation of pore dimensions of media through iteration of the apparent pore size distribution to yield elution data in agreement with experimental data for polymers of known hydrodynamic radius using a simple spread sheet is presented. Data of apparent pore dimensions of some commercial media for aqueous size-exclusion chromatography is presented. The influence of various parameters, e.g., solute shape, pore shape, method errors, etc., is discussed. It is concluded that size-exclusion chromatography can not provide information about the pore structure and, thus, the pore size obtained is dependent upon the selected pore model.