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The recent development of a collection of techniques referred to as direct sampling ion trap mass spectrometry (DSITMS) shows great promise for real-time, high-throughput, low-cost screening of environmental pollutants in air. One of its great strengths is the flexibility it allows the user in choosing among different sample introduction systems, ionization modes, and scan modes. This paper delineates the various stages involved in a DSITMS analysis, describes the options and great flexibility inherent in each of these stages, and demonstrates the use of DSITMS techniques for monitoring trace levels of volatile organic compounds (VOCs) in Mir space station air samples.

A system based on expert systems and ion trap mass spectrometry has been developed to monitor air quality for life support applications. Three different analytical techniques, Thermal Desorption/Gas Chromatography/Mass Spectrometry (TD/GC/MS), Gas Chromatography/Mass Spectrometry (GC/MS), and Mass Spectrometry/Mass Spectrometry (MS/MS), were implemented on this system and evaluated with respect to their potential utility for monitoring major atmospheric constituents, trace levels of known contaminants, and trace levels of unknown compounds in closed environments. TD/GC/MS is an excellent method for characterizing ultratrace levels of volatile organic compounds (VOC's) and has been employed for off-line analysis of air samples collected during several space missions. GC/MS is perhaps the most commonly used method for the analysis of complex mixtures and is currently under development for on-line monitoring of trace contaminants for the space station.