Type of Document Master's Thesis Author Armstrong, Stephanye Dawn URN etd-06162009-063602 Title The effects of carrier gas viscosity on column efficiency in capillary gas chromatography Degree Master of Science Department Chemistry Advisory Committee
Advisor Name Title McNair, Harold M. Committee Chair Long, Gary L. Committee Member Tissue, Brian M. Committee Member Keywords
- gas carriers
- think films
Date of Defense 1995-05-04 Availability restricted Abstract
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.
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.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access LD5655.V855_1995.A767.pdf 2.15 Mb 00:09:56 00:05:06 00:04:28 00:02:14 00:00:11next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.
If you have questions or technical problems, please Contact DLA.