The effects of carrier gas viscosity on column efficiency in capillary gas chromatography
<p>The objective of this study is to determine the effects of carrier gas viscosity of hydrogen and helium on column efficiency; particularly when employing thin films. When using thin films, mass transfer in the stationary phase becomes negligible and mass transfer in the mobile phase pre...
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| Format: | Others |
| Language: | en |
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Virginia Tech
2014
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| Online Access: | http://hdl.handle.net/10919/43351 http://scholar.lib.vt.edu/theses/available/etd-06162009-063602/ |
| Summary: | <p>The objective of this study is to determine the effects of carrier gas
viscosity of hydrogen and helium on column efficiency; particularly when
employing thin films. When using thin films, mass transfer in the
stationary phase becomes negligible and mass transfer in the mobile phase
predominates. It was envisioned that when employing thin films hydrogen
would be the carrier gas of choice due to its higher diffusi vity and lower
viscosity. The combination of the previous factors should lead to faster
analyses (isothermal) and higher column efficiency with hydrogen.</p>
<p>Viscosity is the resistance of a liquid or gas to flow. The viscosity of
a gas is determined by two factors: (1) the molecular weight of the gas;
and (2) its temperature. When the temperature or molecular weight of the
gas is increased its viscosity is also increased. In a chromatographic
system, with a constant pressure drop, an increase in viscosity results in a
decrease in the linear velocity of the carrier gas, ultimately resulting in
lower column efficiency.</p> === Master of Science |
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