The Development of a Volatile Organics Concentrator for Use in Monitoring Space Station Water Quality

An approach to the isolation and concentration of volatile organic compounds from a water sample prior to chemical analysis in a microgravity environment has been previously described (Reference 1). The Volatile Organics Concentrator (VOC) system was designed for attachment to a gas chromatograph/mass spectrometer (GC/MS) for analysis of the volatile organics in water on Space Station Freedom. The VOC concept utilizes a primary solid sorbent for collection and concentration of the the organics from water, with subsequent transfer using nitrogen gas through a permeation dryer tube to a secondary solid sorbent tube. The secondary solid sorbent is thermally desorbed to a gas chromatograph for separation of the volatiles which are detected using a mass spectrometer.

This paper describes the fabrication of a breadboard VOC and preliminary testing of its components with various chemicals of interest in order to optimize its performance and to compare its operation to standard methods in use on earth for water quality analysis. Preliminary results suggest that the breadboard VOC will meet or exceed goals set for the program. Additionally, the VOC has been shown to function for a broader suite of analytes (e.g. iodinated compounds) than those currently analyzed by EPA Method 624 for volatile organics. The VOC also has the potential for improved detection limits over the method currently used on earth (Reference 2) which utilizes purging of the water sample.