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Space Station Freedom presents challenges in water contamination and in the preconcentration of trace contaminants for subsequent analysis. Terrestrial methodologies for the trace level determination of mercury, alcohols, and phenols have been evaluated against levels of detection, complexity, and phase separation requirements. Microgravity compatible modifications of standard methods have been developed and tested. A total mercury sensor, employing solid phase sorption of mercury metal from the analyte followed by determination at a gold film electrode, has been breadboarded and shows a minimum level of detection of less than 0.5ppb. The system uses sodium borohydride as a reagent to facilitate mercury reduction and the decomposition of organomercury compounds. Phenols are determined using a modification of the VOC methodology previously described followed by GC/MS analysis; detection levels below 1ppb have been achieved.

The process used to identify, select and design an approach to the isolation and concentration of volatile organic compounds from a water sample prior to chemical analysis in a microgravity environment is described. The Volatile Organics Concentrator (VOC) system described in this paper has been designed for attachment to a gas chromatograph/mass spectrometer (GC/MS) for analysis of volatile organics in water on Space Station. In this work, in order to rank the many identified approaches, the system was broken into three critical areas. These were gases, volatile separation from water and water removal/GC/MS interface. Five options involving different gases (or combinations) for potential use in the VOC and GC/MS system were identified and ranked. Nine options for separation of volatiles from the water phase were identified and ranked. Seven options for use in the water removal/GC column and MS interface were also identified and included in overall considerations.