ABSTRACT
There are numerous potential applications for meso-and microscale sampling instruments based on mass spectrometry [Nathanson et al., 1995; Ferran and Boumsellek, 1996; Orient et al., 1997; Freidhoff et al., 1999; Wiberg et al., 2000; White et al., 1998; Short et al., 1999; Piltingsrud, 1997] and gas chromatography [Terry et al., 1979]. Other miniaturized instruments utilizing electron optics [Chang, 1989; Chang et al., 1990; Park et al., 1997; Callas, 1999] will require both high vacuum and repeated solid sample transfers from higher pressure environments. The mushrooming interest in chemical laboratories on chips will likely result in manifestations requiring vacuum capabilities. At present, there are no microscale vacuum pumps to pair with the embryonic instruments and laboratories being developed. However, there is now a wider variety of available mesoscale vacuum pumps. Certainly, small vacuum pumps will not always be necessary. Some of the new devices are attractive because of low quantities of waste and rapidity of analysis; not directly because they are small, energy efficient, or need to be portable. However, for other applications involving portability or autonomous operations, small vacuum pumps with suitably low power requirements will be necessary.
