title: Use of peak sharpening effects to improve the separation of chiral compounds with molecularly imprinted porous polymer layer open-tubular capillaries.
abstract: This investigation demonstrates the application of a new peak sharpening technique to improve the separation of difficult-to-resolve racemic mixtures in capillary electro-chromatography. Molecularly imprinted porous layer open tubular (MIP-PLOT) capillaries, prepared by a layer-on-layer polymerization approach with Z-l-Asp-OH as the template, were selected to validate the approach. SEM revealed that the polymer film thickness can be varied by changes in both the polymer composition and the layer-on-layer regime. Capillaries made with methacrylic acid as the functional monomer could not separate the Z-Asp-OH racemate, due to weak interactions between the MIP-PLOT material and the target analytes. In contrast, MIP-PLOT capillaries prepared with 4-vinylpyridine as the functional monomer resulted in increased ionic interactions with the target analytes. Separation of the enantiomers could be enhanced when a peak zone sharpening effect was exploited through the use of specific BGE compositions and by taking advantage of eigenpeak phenomena. In this manner, the position of a sharpening zone and the peak shape of the sample analytes could be fine-tuned, so that when the sharpening zone and the target analyte co-migrated the separation of the Z-l-Asp-OH enantiomer from its d-enantiomer in a racemic mixture could be achieved under overloading conditions.
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), Australian Research Council Special Research Centre for Green Chemistry, School of Chemistry Monash University, Melbourne, Victoria, Australia.
authors.forename: Chadin
authors.initials: C
authors.lastname: Kulsing
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), Australian Research Council Special Research Centre for Green Chemistry, School of Chemistry Monash University, Melbourne, Victoria, Australia.
authors.forename: Yuanzhong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), Australian Research Council Special Research Centre for Green Chemistry, School of Chemistry Monash University, Melbourne, Victoria, Australia.
authors.forename: Jamil M
authors.initials: JM
authors.lastname: Chowdhury
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), Australian Research Council Special Research Centre for Green Chemistry, School of Chemistry Monash University, Melbourne, Victoria, Australia.
authors.forename: Reinhard I
authors.initials: RI
authors.lastname: Boysen
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), Australian Research Council Special Research Centre for Green Chemistry, School of Chemistry Monash University, Melbourne, Victoria, Australia.
authors.forename: Milton T W
authors.initials: MTW
authors.lastname: Hearn
mesh_terms: D001216:Asparagine / Q000031:analogs & derivatives / Q000302:isolation & purification; D053801:Capillary Electrochromatography / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D004867:Equipment Design; D054802:Molecular Imprinting; D011108:Polymers; D011725:Pyridines; D013237:Stereoisomerism
chemical_list: D011108:Polymers; D011725:Pyridines; C117865:benzyloxycarbonyl-asparagine; D001216:Asparagine; C029351:4-vinylpyridine
keywords: Capillary electrochromatography; Chiral separation; Displacement mechanism/ Eigenpeak effects; Layer-on-layer polymerisation