Shielded Stationary Phases Based on Porous Polymer Monoliths for the Capillary Electrochromatography of Highly Basic Biomolecules

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• 作者：Emily F. Hilder ; Frantisek Svec ; and Jean M. J. Fré ; chet
• 刊名：Analytical Chemistry
• 出版年：2004
• 出版时间：July 15, 2004
• 年：2004
• 卷：76
• 期：14
• 页码：3887 - 3892
• 全文大小：89K
• 年卷期：v.76,no.14(July 15, 2004)
• ISSN：1520-6882

文摘

A novel stationary phase for capillary electrochromatography has been prepared via photoinitiated grafting of twolayers of polymer chains onto the pore surface of a porouspolymer monolith. To achieve the desired retention, theoriginal monolith with optimized porous properties wasgrafted with an "interior" layer consisting of the ionizablemonomer, 2-acrylamido-2-methyl-1-propanesulfonic acid,followed by a "covering" layer of hydrophobic polymerchains. This technique affords monolithic CEC columnsthat facilitate electroosmotic flow (EOF) while preventingionized analytes from interacting with the charged surfacefunctionalities. Grafting of the second layer does notadversely affect the EOF. Grafting times of 30 and 60 sfor AMPS and butyl acrylate, respectively, enabled thepreparation of a monolith with full shielding of the analytesfrom the ionizable functionalities and excellent chromatographic performance. This approach allows for the firsttime the independent optimization of both electroosmoticflow and retention properties in CEC columns. Theefficient isocratic separations of mixtures of peptides,including some that are highly basic and would be affectedby unshielded charges, were routinely achieved in 40-90 s using a simple MS compatible mobile phase consisting of 20 mmol/L ammonium acetate in a 1:1 water-acetonitrile mixture.