Evaluation of the porous structures of new polymer packing materials by inverse size-exclusion chromatography.

A highly cross-linked porous polymer resin based on styrene-divinylbenzene matrix with pores created by the use of micellar imprinting technique was used as chromatographic packing material. Its performance as a column packing material in inverse size-exclusion chromatography was compared with a non-imprinted resin of the same polymer matrix. The porous structures (the pore size and the porosity) of the resins in the dry and wet states and their relationships with the elution volume of probe solutes (alkanes and polystyrene standards) were established. Characteristic properties of the resins such as specific pore volume, specific surface area and porosity are compared with results obtained by other methods of characterization such as mercury intrusion porosimetry, solvent regain and nitrogen sorption. The results show that the new porous resin can be used in the separation of small molecules. The separation is based on the size of the molecules, and the larger pores (meso- and macropores) in the porous resin can provide a much easier access to the smaller pores (micropores) which are useful in the chromatographic separations.

A static and dynamic light scattering study of sharp pectin fractions in aqueous solution.

A number of sharp fractions from low methoxyl citrus pectin have been studied using dynamic and static light scattering and size exclusion chromatography. The efficiency of the dynamic light scattering technique for the characterization of aqueous pectin solutions is demonstrated even when aggregages are present. The measured molar mass dependence of the Stokes radius confirms the semi-rigid structure of pectin. The effect of a number of sample manipulations on the aggregate content has been investigated and a simple but effective purification method is presented.