Theoretical and nomenclatural considerations of capillary electrochromatography with monolithic stationary phases

Végvári, Ákos; Guttman, A J

doi:10.1002/elps.200500789

Cited by 15 publications

(5 citation statements)

References 101 publications

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“…Small internal diameter columns of high efficiency have several advantages, such as reduction in consumption of chemicals (including stationary and mobile phases), minimal sample requirement, and a higher mass sensitivity due to a lower chromatographic dilution. Another advantage of capillary columns is their applicability in capillary electrochromatography, where the electroosmotic flow is used instead of hydraulic pumping to convey the mobile phase …”

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confidence: 99%

Assessing the Macroporous Structure of Monolithic Columns by Transmission Electron Microscopy

et al. 2006

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A set of monolithic stationary phases representing a broad span of monomers and porogens have been characterized directly in their capillary chromatographic format by computational assessment of their pore structure from transmission electron micrographs obtained after in situ embedment of the monoliths in contrast resin, followed by dissolution of the fused-silica tubing, further encasement of the resin-embedded monolith, and microtomy. This technique has been compared to mercury intrusion, a more conventional technique for macroporosity estimation. Supplementing the embedding resin by lead methacrylate gave a negative staining, and the resulting micrographs showed a good contrast between the polymeric monoliths and the embedding resin that allowed studies on the pore formation and polymer development. The technique was also applied to a commercial monolithic silica column.

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confidence: 99%

Assessing the Macroporous Structure of Monolithic Columns by Transmission Electron Microscopy

et al. 2006

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“…To narrow the scope, most of the attention is paid to recent reports. It needs to be emphasized that this paper is not a comprehensive review since a number of excellent review articles summarizing in great detail various aspects of CEC using monolithic columns have been published recently 37–52. Also, the readers should understand that selection of all of the bits and pieces presented below is subjective and biased by what I thought to be interesting or curious.…”

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confidence: 99%

CEC: Selected developments that caught my eye since the year 2000

Švec

2009

Electrophoresis

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During the last decade, a number of new developments have emerged in the field of capillary electrochromatography (CEC). This paper focuses only on monolithic columns prepared from synthetic polymers. Monolithic columns have become a well-established format of stationary phases for CEC immediately after their inception in the mid 1990s. They are readily prepared in situ from liquid precursors. Also, the control over both porous properties and surface chemistries is easy to achieve. These advantages make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials. Since the number of papers concerned with just this single topic of polymer-based monolithic CEC columns is large, this overview describes only those approaches this author found interesting. KeywordsMonolith; Capillary; Electrochromatography; Microfluidic devices; Review PrologueIt is the second half of the 1990s. The monoliths are in their infancy with a multiplicity of their formats being developed just within the last few years [1][2][3][4]. Only a handful of groups were working with these new materials and exploring their applications mostly for the separations in liquid chromatography. At the same time, electrochromatography rose from ashes like the mythical Phoenix. This separation method has been proposed by Pretorius already in 1974 [5]. He realized the advantage of the flat flow profile generated by electroosmotic flow (EOF) that was supposed to reduce peak broadening thus affording better column efficiency in both thin layer and column chromatography. However, for a couple of decades his technique has been almost forgotten. The 1990s featured search for new microseparation methods with vastly enhanced efficiencies, peak capacities, and selectivities needed for the emerging fields of life science and pharmaceuticals and CEC became one of the targets. The new interest in CEC has also been fueled by discoveries such as that by Smith who demonstrated that extreme column efficiencies exceeding one million of plates could be achieved using CEC in packed capillary columns although these were difficult to reproduce [6]. Results like these evoke curiosity of many researchers and jump started CEC.Capillary electrochromatography has been defined as a high-performance liquid phase separation technique carried out in columns packed with media containing ionizable functionalities that utilizes flow driven by electroosmosis and enables to achieve significantly improved performance compared to high performance liquid chromatography (HPLC). The Correspondence: Frantisek Svec, The Molecular Foundry, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8197, USA. fsvec@lbl.gov Phone +510 486 7964. NIH Public Access Author ManuscriptElectrophoresis. Author manuscript; available in PMC 2010 June 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript frequently published definitions that call CEC a hybrid of capillary electrophoresis (CE) and HPLC are actually not comple...

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“…Electrokinetic injection was used: the dye mixture was put into the reservoir, 50 V/cm was applied for 5 s, then the voltage was turned off and the sample replaced with mobile phase. This differs from electrochromatography in that there is no flow. Figure a shows the separation of the three DiIs.…”

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confidence: 94%

High-Speed Electroseparations Inside Silica Colloidal Crystals

et al. 2006

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Crystals made from 200 nm silica colloids are hardened and chemically modified with chlorodimethyloctadecylsilane for use in electrically driven, reversed-phase separations. A van Deemter plot reveals extremely narrow peak widths for the separation of a cationic hydrophobic dye, DiI, with both the A and C terms 10-fold smaller than those for a conventional HPLC column. Electrically driven separations are demonstrated to be achieved in less than 10 s for three dyes differing in hydrophobicity and also for three peptides differing in electrophoretic mobility. The results show that these media are promising for high-speed separations.

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Theoretical and nomenclatural considerations of capillary electrochromatography with monolithic stationary phases

Cited by 15 publications

References 101 publications

Assessing the Macroporous Structure of Monolithic Columns by Transmission Electron Microscopy

Assessing the Macroporous Structure of Monolithic Columns by Transmission Electron Microscopy

CEC: Selected developments that caught my eye since the year 2000

High-Speed Electroseparations Inside Silica Colloidal Crystals

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