Identifier

etd-01212009-142138

Degree

Master of Science (MS)

Department

Environmental Sciences

Document Type

Thesis

Abstract

Gas chromatography (GC) is a widely used analytical technique, with applications in the chemical process industry, oil exploration, environmental monitoring, purification of substances, and general organic compound analysis. Although traditional GC’s are widely used they have their own disadvantages like high power consumption and long times for analysis. Several laboratories are working on the miniaturization of GC’s for rapid and onsite chemical analysis. Many researchers are currently working on the development of microfabricated columns for realizing a hand held GC sensor. Microfabricated nickel columns have been manufactured by Center for Advanced Microstructures & devices (CAMD), Baton Rouge. The columns are attractive due to their small size, low thermal mass and high thermal conductivity allowing for rapid temperature programming with relatively low power consumption and parallel manufacturing which results in low manufacturing costs, and robustness when compared to silicon columns. Using the LiGA process nickel columns with width dimensions of 50 microns, height dimensions of 500 microns and 1 meter of channel length are microfabricated with integrated on chip injection and detection connections. Connecting these column chips to the HP 5890 GC test bed is described. A commercial fused silica capillary column of 1 meter length, 100 microns i.d was tested to check the instrument set up and for providing background performance data. The microfabricated nickel column chips were tested with the same conditions after the PMMA (Poly methyl methacrylate) removed, after deactivation, and after coating. The test mixtures were methane, hexane and mixture of hexane and decane. Different methods of deactivation and coating these metal columns have been described. Columns were coated with dimethyl polysiloxane stationary phase (OV-1). Separation of methane and hexane was performed in less than 4 seconds. The preliminary experimental results on these coated high aspect ratio metal gas chromatography columns displayed promising results and future research is mainly focused on coating methods to achieve more uniform coatings without any pooling of the solution in the column’s corners and for separation of different chemical compounds.

Date

2009

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Edward Overton

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