Effect of electric field on the partitioning behavior of solutes in entropic interaction chromatography

Abstract

In this study, a novel column design with a round cross-section was proposed to be suitable for a transverse electric field (EF). Additionally, two beads for entropic interaction chromatography (EIC) were prepared by grafting glycidyl methacrylate onto Toyopearl HW-65F (T65F) beads. Solute partitioning was then investigated to elucidate the role of graft polymerization with and without an EF. In a T65F column, solute partitioning was attributed to the distinct pore structure in the beads and was governed by pore flow. Under EF, partition coefficients (Kp) for solutes decreased with increasing EF strength. In the two EIC columns, a decrease of Kp was also observed without an EF while the fractionation windows were extended. It was more pronounced in the EIC column with a high grafting density (T65F-H). This was explained by the decrease in the effective pore size of solutes caused by the steric hindrance of polymer chains. Under an EF, the solutes showed different partitioning behaviours in the T65F-H column. With increasing EF strength, Kp for vitamin B12 and myoglobin was decreased. In contrast, Kp for large solutes increased as a result of concentration polarization on the bead surface. Both behaviors were related to the modulation of graft polymerization to residual charge on the matrix and the pore size of the solutes.

Fabrication of high-capacity protein ion-exchangers with polymeric ion-exchange groups grafted onto micron-sized beads by atom transfer radical polymerization

“…Therefore, pGMA-H-DMCH had a much lower adsorption capacity for γ-globulin than pGMA-M-DMCH. The same finding was reported by several groups in polymer-grafted size exclusion chromatographic beads [32][33][34]. Therefore, the BIBB density should be optimized to achieve the maximal adsorption capacity for proteins.…”

“…Protein adsorption in charged polymer chains grafted from a solid surface is considered a complicated phenomenon controlled by electrostatic interactions between the charged polymer and proteins and dependent on the chain configuration of the charged polymer [31]. The latter effect was more dramatic in denser polymer chains extending from the pore surface [32]. In polymer-grafted ion-exchange beads, proteins were more prone to exclusion from the polymer chain with increasing polymer chain density.…”