Preparation of surface-modified wide-bore wall-coated open-tubular columns

Onuska, Francis I.; Comba, Michael E.; Bistricki, T.; Wilkinson, Robert J.

doi:10.1016/s0021-9673(01)92031-x

Cited by 73 publications

(27 citation statements)

References 6 publications

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“…The etching process increases the surface area of the capillary by a factor of up to 1000 [153]. Therefore, more stationary phase can be attached to the wall, which in turn, increases the loading capacity of the column.…”

Section: Chemical Bonding After Etchingmentioning

confidence: 99%

“…This creates radial extensions from the wall that decrease the distance an analyte has to travel in order to interact with the stationary phase [96]. The etching process was first introduced by Onuska et al [153] for gas chromatography (GC), and it was then modified for OT-CEC by Pesek et al [3,28,30,[77][78][79][80][154][155][156][157][158][159][160][161][162].…”

Section: Chemical Bonding After Etchingmentioning

confidence: 99%

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Analytical separations in open‐tubular capillary electrochromatography

Kapnissi‐Christodoulou

Zhu

Warner

2003

Electrophoresis

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This review represents a summary of recent progress in open-tubular capillary electrochromatography (OT-CEC) for chiral and achiral separations. The OT-CEC approach is an alternative to packed-CEC that could eliminate the problems associated with retaining frits and silica particles. In OT-CEC, the stationary phase is immobilized on the inner walls of the capillary. Preparation of the stationary phase is critical for OT-CEC. The preparation methods for capillary columns include (i) adsorption, (ii) covalent bonding and/or cross-linking, (iii) porous layers, (iv) chemical bonding after etching, (v) sol-gel, and (vi) molecular imprinting. Major developments, potential applications, technical difficulties and advantages associated with these wall coatings in OT-CEC are presented. In addition, the coupling of OT-CEC with mass spectrometry (MS) is briefly reviewed. Several applications of this hyphenated technique for analytical separations are also summarized.

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Section: Chemical Bonding After Etchingmentioning

confidence: 99%

Section: Chemical Bonding After Etchingmentioning

confidence: 99%

Analytical separations in open‐tubular capillary electrochromatography

Kapnissi‐Christodoulou

Zhu

Warner

2003

Electrophoresis

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“…Such chemically modified, surfaceetched capillaries are less adsorptive than naked, fused silica [6]. In addition, during the etching procedure, the surface area of the inner surface can be increased by up to 1000-fold with radial silica protrusions extending from the surface by as much as five mm [7]. Both of these features enhance the ability of peptide analytes to interact with stationary phases bonded to this new surface.…”

Section: Introductionmentioning

confidence: 99%

Open‐tubular electrochromatographic characterization of synthetic peptides

et al. 2004

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The open-tubular electrochromatographic (OT-CEC) migration behavior of a series of peptides, based on a common structural feature, has been characterized using two different types of chemically modified etched capillaries. The organic moieties immobilized onto the capillary inner surface were n-butylphenyl and cholesterol-10-undecenaoate, respectively. The structure-migration behavior of this set of peptides has been studied at several pH values and with methanol at different concentrations as an organic solvent modifier of the buffer electrolyte composition. By comparing the structural properties of the peptides, such as their amino acid sequences, charge-to-mass ratios and intrinsic hydrophobicities to their migrational behavior, the relative contribution of electrophoretic and chromatographic mobility to the overall migration times, elution order, and selectivity has been determined. Moreover, the experimental data provide important insight into procedures that can be used to modulate the separation of peptides in OT-CEC through variation of the composition of the electrolyte buffer as well as via the properties of the bonded organic moiety.

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“…In order to fabricate this separation medium, the inner wall of a fused-silica capillary is etched by heating it at a temperature of 300-4001C in the presence of ammonium hydrogen difluoride (NH 4 HF 2 ) for 3-4 h. This process increases the surface area of the inner wall by a factor of 1000 or more and can produce radial extensions of up to 5 mm in length [15,16]. This treatment has two functions: to increase the capacity of the bare capillary and to shorten the distance solutes must travel in order to interact with a stationary phase attached to the etched surface.…”

Section: Introductionmentioning

confidence: 99%

Open‐tubular capillary electrochromatography of small polar molecules using etched, chemically modified capillaries

2011

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The migration characteristics of small polar molecules are evaluated on etched, chemically modified capillaries with four different moieties (C5, C18, diol and cholesterol) bonded onto a silica hydride surface. The effects of pH on migration are used to determine the possible contributions of eletrophoretic mobility, electroosmotic flow (EOF) and analyte/bonded phase interactions. The EOF on etched capillaries is more complicated than on ordinary fused capillaries because it changes from anodic to cathodic as the pH is raised. A mixture of neurotransmitters and related compounds is used to further evaluate the effects of the bonded moiety on the separation properties of this particular electrophoretic format.

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Preparation of surface-modified wide-bore wall-coated open-tubular columns

Cited by 73 publications

References 6 publications

Analytical separations in open‐tubular capillary electrochromatography

Analytical separations in open‐tubular capillary electrochromatography

Open‐tubular electrochromatographic characterization of synthetic peptides

Open‐tubular capillary electrochromatography of small polar molecules using etched, chemically modified capillaries

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