Master of Science in Mechanical Engineering (MSME)
Gas chromatography is a technique widely used for the separation and analysis of gas samples. Gas chromatographs are used for environmental maintenance, monitoring sophisticated biological analyses, and to separate components from a mixture of gases for mass spectrometer analysis. There has been a tremendous interest in miniaturization of gas chromatograph systems because of the potential for portability, faster response time, lower dead volume, lower power consumption, and lower cost of operation. Conventional gas chromatography keeps the column at a constant temperature during separation, which is called isothermal analysis. Temperature programming is a mode of gas chromatography in which the column temperature is raised progressively during the course of analysis. Temperature programming facilitates separation of a wider range of components, when compared to isothermal analysis, in less time. No miniaturized gas chromatograph systems with temperature programming capability have been reported to date. A temperature programming cycle was implemented for the LSU microGC. The thermal behavior of the device was modeled using an energy-based approach to determine the thermal power requirements. Two heaters were designed, one heater gave uniform temperature distribution over the LSU microGC column, and the other gave a linear temperature gradient along the length of microGC. The heaters were fabricated by electrodepositing Ni-Cr (97.5-2.5) alloy on silicon substrates. The heaters were integrated with test microGC. A commercial PID controller was integrated with the heater and fan to direct the temperature programming for the LSU microGC. Heating and cooling ramp rates of more than 2.46 oC/sec were obtained.
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Pasupuleti, Praveen K., "Thermal management of the LSU micro gas chromatograph" (2005). LSU Master's Theses. 2252.
Michael C. Murphy