Porosity and hydrophobicity of chromatographic resins effect on performance
Methacrylic and styrenic-based resins differ significantly in their hydrophobicity, offering advantages in chromatographic processes when a combination of the two are available. By combining both resin backbones and introducing a variance in pore diameter, it is possible to cover a wide range of chromatographic conditions and optimise for a particular separation.
Herein are described the results of physical and chemical characterisation of a range of commercially available synthetic polymeric resins, both methacrylic and styrenic. The relationship between porosity, hydrophobicity and suitability for specific applications is investigated and the differences identified. The higher uniformity resins are shown to have excellent results for mechanical stability and monodispersity, and the link between larger pore diameters and increased binding capacity is demonstrated.
A range of commercially available chromatographic resins have been characterised and compared in terms of chemical and physical characteristics related to applications such as protein purification. Table 1 reports on two classes of absorbents that can be used in biomolecule purification: highly hydrophobic adsorbents based on a divinylbenzene backbone and medium hydrophobicity adsorbents, based on a methacrylic backbone. Adsorbents based on divinylbenzene show very strong hydrophobic interactions with biomolecules so elution occurs mainly by reverse-phase mode using organic solvents, whereas the methacrylic adsorbents are less hydrophobic and elution can occur faster and with less organic solvent. One of the key advantages of using rigid and hydrophobic adsorbents is that they are chemically inert and stable to a wide pH range and the majority of organic solvents. Highly rigid resins also minimize the swelling and shrinking in column set-up, simplifying process design.
Table 1 shows a selection of chromatographic adsorbents based on a divinylbenzene or methacrylate matrix, all with a mean pore diameter below 500 Å. The d ...