| This thesis presents the theory, design, fabrication and testing of the microvalves and columns necessary in a pressure- and temperature-programmed micro gas chromatograph (muGC). Two microcolumn designs are investigated: a bonded Si-glass column having a rectangular cross section and a vapor-deposited silicon oxynitride (Sion) column having a roughly circular cross section. Both microcolumns contain integrated heaters and sensors for rapid, controlled heating. The 3.2 cm x 3.2 cm, 3 m-long silicon-glass column, coated with a non-polar polydimethylsiloxane (PDMS) stationary phase, separates 30 volatile organic compounds (VOCs) in less than 6 min. This is the most efficient micromachined column reported to date, producing greater than 4000 plates/m. The 2.7 mm x 1.4 mm Sion column eliminates the glass sealing plate and silicon substrate using deposited dielectrics and is the lowest power and fastest GC column reported to date; it requires only 11 mW to raise the column temperature by 100°C and has a response time of 11s and natural temperature ramp rate of 580°C/min. A 1 m-long PDMS-coated Sion microcolumn separates 10 VOCs in 52s. A system-based design approach was used for both columns.; The 7.5 mm x 10.3 mm integrated microvalve enables low-power pressure programming of the dual-column ensemble and is the first microvalve to utilize a hybrid actuation mechanism consisting of a thermopneumatic drive with an electrostatic hold. The valve has an open flow rate of 8 scan at 4.6 torr, a leak rate of 1.3 x 10-3 sccm at 860 torr, a closed-to-open fluidic resistance, ratio greater than one million, an actuation time of 430 ms, and a hold power of 60 mW while closed. In addition, the valve requires no power to open, 108 mJ to close, and has a built-in position sensor with a sensitivity of 1.3 fF/torr. The design of an improved microvalve that should require only 35 mJ to close in 140 ms, a hold power of 6 mW without electrostatic latching, and no hold power with an electrostatic voltage of 180V is presented.; Overall, the valve and columns presented in this dissertation set the stage for high-performance, portable, vapor analysis instruments. |
