Capillary electrochromatography with zwitterionic stationary phase on the lysine‐bonded poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) monolithic capillary column

Abstract

A polymer-based neutral monolithic capillary column was prepared by radical polymerization of glycidyl methacrylate and ethylene dimethacrylate in a 100 mum id fused-silica capillary, and the prepared monolithic column was subsequently modified based on a ring opening reaction of epoxide groups with 1 M lysine in solution (pH 8.0) at 75 degrees C for 10 h to produce a lysine chemically bonded stationary phases in capillary column. The ring opening reaction conditions were optimized so that the column could generate substantial EOF. Due to the zwitterionic functional groups of the lysine covalently bonded on the polymer monolithic rod, the prepared column can generate cathodic and anodic EOF by varying the pH values of running buffer during CEC separation. EOF reached the maximum of -2.0 x 10(-8) m2v(-1)s(-1) and 2.6 x 10(-8) m2v(-1)s(-1) with pH of the running buffer of 2.25 and 10, respectively. As a consequence, neutral compounds, ionic solutes such as phenols, aromatic acids, anilines, and basic pharmaceuticals were all successfully separated on the column by CEC. Hydrophobic interaction is responsible for separation of neutral analytes. In addition, the electrostatic and hydrophobic interaction and the electrophoretic migration play a significant role in separation of the ionic or ionizable analytes.

Monolithic porous polymer stationary phases in polyimide chips for the fast high-performance liquid chromatography separation of proteins and peptides

“…The morphology of the monolithic polymer is strongly affected by both the composition of the polymerization mixture and the conditions under which the polymerization process is carried out [21,28,29]. The different monoliths have thus been optimized for specific applications by tuning them with a wide range of functionalities [29,32,33], among which hydrophobic [27,28,34] hydrophilic [35], ionizable [28,34], and reactive [36,37] are the most frequently used.…”

Recent progress in polar stationary phases for CEC

“…More recently, Dong et al [74] immobilized lysine onto the poly(glycidyl methacrylate (GMA)-co-EDMA) monolithic capillary columns based on a ring opening reaction of epoxide groups with lysine. It was due to the zwitterionic functional groups of lysine that the prepared column could generate cathodic or anodic EOF by varying the pH value of mobile phases.…”

Novel negatively charged tentacle‐type polymer coating for on‐line preconcentration of proteins in CE

“…The magnitude of EOF in the capillary columns is dependent on the net surface charge density of chargeable groups [26]. For the polymer-coated column, they are sulfonic acid groups functionalized on the coated polymer and some residual silanol groups.…”