Research-Grade and Large-Scale Drift Tubes at Ambient Pressure

1 Research-Grade and Large-Scale Drift Tubes at Ambient Pressure 

FIGURE 6.1 A block diagram of the main components of a generic ion mobility spectrometer regardless of mobility method. Any ion mobility instrnment will be comprised of a drift tube, which includes an ion sonrce, region for mobility characterization, detector and the utilities needed to support the measurement. This usually involves flows of purified gases, power supplies, and temperature control. Options for ion sources were described in Chapter 4, and methods for ion injection were presented in Chapters. 

FIG U RE 6.3 (a) Photograph of drift tube at ambient pressure with resolving power in excess 

Efforts to join liquid chromatographs (LCs) and IMSs at ambient pressure and with full flow of conventional columns has not been developed since stable response and high-quality spectra can be obtained at flow rates up to about 2 pL/min. Mobility spectrometers with direct flux of ESI spray into the drift tube become inoperable with liquid flows larger than 10 pL/min or liquid compositions with 50% or more water, even with a desolvation region. An interface was described to accept full liquid flow from an LC directly into the drift tube and consisted of three stainless steel rings in a Teflon housing with a stainless steel mesh welded on the third ring. 

Reverse source flow design. Another innovation in drift tube design, associated also with isolating the reaction region from sample vapors, is a drift tube based on 

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