Gel filtration media play a very important role in separation and purification of bio-macromolecules such as proteins

polysaccharides.Their pore structure directly influences protein transport and adsorption in chromatographic separation column.The pore size distribution(PSD)plays a major role beyond simply the mean pore size.Various methods have been employed to determine the PSD of porous materials

including gas adsorption-desorption(BET)

mercury intrusion porosimetry(MIP).Since most of gel filtration media is soft gel

so it is difficult to measure their PSD by conventional method.In this paper

a new method

low-field NMR

was explored to determine the pore size distribution of gel filtration media.First

the distribution range of internal water

external water and free water in transverse relaxation time(T2)of low-field NMR were setting-out; then comparing the results with that from inverse size-exclusion chromatography(ISEC)and finding relationship between the pore size and relaxation time in internal water; finally

the pore size distribution of media was fitted by the Gaussian normal distribution.The results demonstrated that low-field NMR is an effective method for PSD determination of porous chromatographic media.The method is easy to operate

simple and quick

and can provide a reference for other determination of chromatography media pore size distribution.