Abstract:

The method of inverse size-exclusion chromatography (ISEC) was established to determine the pore size distribution (PSD) of porous chromatographic media.Two well-known pore size distribution (PSD) models，Gaussian distribution and log-normal distribution，were investigated in the present work.The most used local partition coefficient model was adopted with the assumption of rigid spherical solutes in the cylindrical pores.Then the relationship between PSD and the theoretical distribution coefficient K_d was established.After the measurement of K_d with a series of molecule standards by size-exclusion chromatography，the information of PSD could be obtained with the correlation of calculated Kd to the experimental data.In the present work，K_d of five typical chromatographic media，SP Sepharose FAST FLOW，Q Sepharose FAST FLOW，Toyopearl DEAE-650M，Streamline DEAE and Sephadex G-150，were measured by using dextrans as the standards.Then the PSDs of five media tested were determined by the method of ISEC.The model calculation fitted well with the experimental data，and the PSDs of different media were analyzed.In addition，the accessible internal pore surface area was calculated and discussed.The results demonstrated that ISEC is a feasible method to determine the PSD of porous chromatographic media.