Capillary supercritical fluid chromatography

The modification of a gas chromatograph for capillary supercritical fluid was demonstrated. The resulting instrument was used to characterize the performance of capillary columns manufactured specifically for SFC applications. The columns were tested for inertness, efficiency, and immobilization before and after extraction with the supercritical CO₂ solvent. Stable deactivation layers were obtained with polyethylene glycol pyrolysis of Carbowax 20M and Superox 20M. Crosslinking was evaluated with dicumyl peroxide (DCP) and azo-t-butane (ATB) as free radical initiators with OV-1701 as a stationary phase. ATB was found to yield more efficient crosslinking and had less effect on column polarity. Quantitative reproducibility of SFC was evaluated for alkanes, alcohols and acids on columns which were deactivated by polyethylene glycol pyrolysis or by mixed cyclic siloxanes. Both gave better reproducibility than an untreated column but the overall reproducibility of the polyglycol deactivation was better than the cyclic deactivation. Liquid CO₂ extraction was performed on a variety of spices and food products. This sample preparation proved useful in isolating CO₂ soluble materials from complex matrices which were insoluble in CO₂.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Chemistry

Department dc:contributor.department

Chemistry

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1986

Author dc:creator

• Hensley, Jack Lee

Chair dc:contributor.committeechair

• McNair, Harold M.

Committee members dc:contributor.committeemember

• Bell, Harold M.
• Taylor, Larry T.
• Mason, John G.
• Wightman, James P.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/53623

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/53623