Deactivation of fused silica capillary columns with polymethylhydrosiloxanes

Woolley, C. L.; Kong, R. C.; Richter, Bruce E.; Lee, M. L.

doi:10.1002/jhrc.1240070608

Cited by 63 publications

(14 citation statements)

References 7 publications

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“…used silica tubing (Spectran Corp., Sturbridge, MA). Column deactivation was achieved by purging with nitrogen at 350 °C for several hours followed by silylation with a poly(methylhydrosiloxane) (11) and treatment with chlorotrimethylsilane at 250 °C. After deactivation, the columns were coated with ~0.15-gm film of 5% phenyl poly(methylphenylsiloxane) (SE-54) and cross-linked with azo-t-butane (12).…”

Section: Methodsmentioning

confidence: 99%

Pressure programming in supercritical fluid chromatography

Smith¹,

Chapman²,

Wright³

1985

Anal. Chem.

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Section: Methodsmentioning

confidence: 99%

Pressure programming in supercritical fluid chromatography

Smith¹,

Chapman²,

Wright³

1985

Anal. Chem.

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“…The concentration of silanols on the surface can be increased by acidic or basic etching or reduced by chemical reactions such as the common silane derivatization or reaction with siloxanes containing silane (Si-H) groups (Lee et al 111). …”

Section: Modification Of Electroosmotic Flow and Analytementioning

confidence: 99%

Modification of silica surfaces for CZE by adsorption of non‐ionic hydrophilic polymers or use of radial electric fields

Belder

Schomburg

1992

J. High Resol. Chromatogr.

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SummaryPolyvinylalcohols (PVA) and hydroxyethylcelluloses (HEC) have been used as additives in cyclodextrin-modified capillary zone electrophoretic chiral separations of aromatic amines such as tocainide and its analogs in unpretreated 50 pm i.d. fused silica capillaries. The additives were used at low concentrations the intended sersarations adsorption of analyte molecules This seriously affects the efficiency of the separations strong surface interaction degrades the symmetry of the eluted zones, changes the absolute and relative migration times, and, as a consequence, reduces the resolution of (<0.05 Yo) in common buffers, together with the y-cyclodextrin as chiral selector. They reduce the electroosmotic flow, i.e. increase the migration times of the analytes in these chiral separations, and, moreover, considerably improve both peak symmetry and the widths of the peaks relative to migration time. In terms of the chromatographic theory of efficiency, more than 200000 theoretical plates can be achieved with unpretreated fused silica capillaries. This enhancement of efficiency arises because adsorptive "dynamic" coating with the hydroxylic modifier molecules suppresses adsorption of the analyte molecules by the capillary walls.The influence of field strength and buffer composition on the separation efficiency attainable with and without modifier in the buffers has also been investigated. Alternative experiments on the influence of analyte adsorption on efficiency have been performed by superimposing radial electric fields on the capillary to modify the 5 potentials. Although the EOF could be freely adjusted, it was not possible to obtain an improvement in efficiency comparable with that furnished by coating the adsorptive surface with PVA or HEC.

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“…When this column is deactivated with a precoating of Carbowax 20M, the residual surface column is considerably reduced (Figure 3.21b). A variety of agents and procedures have been explored for deactivation purposes (60)(61)(62)(63)(64)(65)(66)(67)(68)(69)(70)(71)(72)(73)(74). For subsequent coating with nonpolar and moderately polar stationary phases such as polysiloxanes, fused silica has been deactivated by silylation at elevated temperatures, thermal degradation of polysiloxanes and polyethylene glycols, and the dehydrocondensation of silicon hydride polysiloxanes (71,(75)(76)(77)(78)(79).…”

Section: Silanol Deactivationmentioning

confidence: 99%

Columns: Packed and Capillary; Column Selection in Gas Chromatography

Barry

2004

Modern Practice of Gas Chromatography

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Deactivation of fused silica capillary columns with polymethylhydrosiloxanes

Cited by 63 publications

References 7 publications

Pressure programming in supercritical fluid chromatography

Pressure programming in supercritical fluid chromatography

Modification of silica surfaces for CZE by adsorption of non‐ionic hydrophilic polymers or use of radial electric fields

Columns: Packed and Capillary; Column Selection in Gas Chromatography

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