title: 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.
authors.affiliation: Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.
authors.forename: Qing-Hong
authors.initials: QH
authors.lastname: Shi
authors.forename: Guo-Dong
authors.initials: GD
authors.lastname: Jia
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
mesh_terms: D002845:Chromatography / Q000295:instrumentation*; D004574:Electromagnetic Fields; D019277:Entropy; D004852:Epoxy Compounds / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry / Q000302:isolation & purification*; D011108:Polymers / Q000737:chemistry; D014805:Vitamin B 12 / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D004852:Epoxy Compounds; D008689:Methacrylates; D009211:Myoglobin; D011108:Polymers; C044554:Toyopearl HW-65F; D014805:Vitamin B 12; C007870:glycidyl methacrylate
keywords: Concentration polarization; Effective pore size; Electric field; Entropic interaction chromatography; Graft polymerization