High-performance temperature-programmed microfabricated gas chromatography columns

This paper reports the first development of high-performance, silicon-glass micro-gas chromatography (mu GC) columns having integrated heaters and temperature sensors for temperature programming, and integrated pressure sensors for flow control. These 3-m long, 150-mu m wide and 250-mu m deep columns, integrated on a 3.3 cm square die, were fabricated using a silicon-on-glass dissolved wafer process. Demonstrating the contributions to heat dissipation from conduction, convection, and radiation with and without packaging, it is shown that using a 7.5-mm high atmospheric pressure package reduces power consumption to about 650 mW at 100 degrees C, while vacuum packaging reduces the steady-state power requirements to less than 100 mW. Under vacuum conditions, 600 mW is needed for a temperature-programming rate of 40 degrees C/ min. The 2300 ppm/degrees C TCR of the temperature sensors and the 50 fF/kPa sensitivity of the pressure sensors satisfy the requirements needed to achieve reproducible separations in a mu GC system. Using these columns, highly resolved 20-component separations were obtained with analysis times that are a factor of two faster than isothermal responses.