Chiral electrochromatography with a ‘moulded’ rigid monolithic capillary column

Abstract

Several monolithic chiral stationary phases for reversed-phase electrochromatography have been prepared within the confines of untreated fused silica capillaries by the direct copolymerization of the chiral monomer 2-hydroxyethyl methacrylate (N-L-valine-3,5dimethylanilide) carbamate with ethylene dimethacrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid and butyl or glycidyl methacrylate in the presence of a porogenic solvent. The hydrophilicity of the stationary phase, which may be enhanced further by the hydrolysis of the epoxide functionalities of the glycidyl methacrylate moieties within the monolith, was found to have a pronounced effect on the enantioseparation. Using the most hydrophilic monolithic capillary column and optimized elution conditions, a separation of N-(3,5-dinitrobenzoyl)leucine diallylamide enantiomers with an efficiency of 61 000 plates m 21 and a resolution of 2.0 was achieved.

Chiral separation by chromatographic and electromigration techniques. A Review

“…Peters et al [534] reported the preparation of a 'moulded' monolithic CSP by copolymerization of the chiral monomer 2-hydroxyethyl methacrylate (n-l-valine-3,5-dimethylanilide) carbamate with ethylene dimethylacrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid and butyl or glycidyl methacrylate in the presence of a porogenic solvent. The applicability of this phase to chiral CEC separation was tested using N-(3,5-dinitrobenzoyl)leucine diallylamide as a model compound.…”

Stability and repeatability of capillary columns based on porous monoliths of poly(butyl methacrylate-co-ethylene dimethacrylate)

“…Since their invention in the early 1990s, rigid porous polymer-based monolithic columns have shown their unique suitability for the rapid separations of large molecules such as proteins [1][2][3][4][5], nucleic acids [6][7][8], and synthetic polymers [9][10][11]. The original analytical scale size columns were supplemented with their capillary counterparts in the early 2000s [5,[12][13][14][15][16][17][18][19].…”

Enantiomer Separation by Capillary Electrochromatography Using Fritless Packed Columns

“…There are a number of variables that affect the porous structure and hence the flow properties of the macroporous materials, including the nature and concentration of monomer, crosslinker, porogenic solvent and initiator, reaction time, the content of chiral monomer and the initiation method. Peters et al 18 introduced rigid macroporous fritless packed columns for chiral CEC separations. The columns were prepared by in situ polymerization of 2-hydroxyethyl methacrylate (N-L-valine-3,5-dimethylanilide) carbamate (enantioselective monomer) with EDMA (crosslinker), sodium salt of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS, cathodic EOF generator) and gycidyl methacrylate (GMA, comonomer) in the presence of a porogenic solvent (a mixture of propan-1-ol, butane-1,4-diol and water) and AIBN.…”

“…18 Furthermore, these polymerizations are often terminated prior to completion, making exact control of the final polymer morphology and composition problematic. Rigid macroporous fritless packed columns have the advantage of allowing the mobile phase to be transported by pressurized flow.…”