The Savannah River Site (SRS) has processed hydrogen isotopes for storage applications for over 50 years. The Savannah River National Laboratory (SRNL) was created to support the research and development tasks of the various processing efforts at the SRS, including hydrogen processing. Optimization of hydrogen processing conditions must be accomplished by monitoring process conditions such as ammonia and moisture levels. Most commercially available ammonia and moisture sensors rely on electrolytic permeable polymers for detection. These permeable polymers suffer from the lack of resolving power to differentiate between ammonia and moisture and rely on electrolytic measurements in a potentially explosive (> 4% H2) environment. To overcome these limitations, researchers at SRNL have been collaborating with researchers at the University of Minnesota and the Center for Process Analytical Chemistry to employ fluorescence emission from inorganic complexes (vapochromes) to detect both vapor phase moisture and ammonia. These vapochromic crystals show both intensity changes and signature shifts in the fluorescence maximum after sorption of various gas phase analytes. A partial least squares (PLS) algorithm was utilized to evaluate the sensor response to ammonia. A 3-priniciple component (PC) model was found to precisely describe the variation in the signal over a concentration range of 0.3-3.0%. After accounting for the variation, the data was found to track linearly with a correlation coefficient of 0.9998. In this presentation, results from evaluating vapochromic compounds in the presence of ammonia and moisture will be discussed, as well as, testing under process conditions.
Back to Chemical Sensors: New Frontiers (General Session)
Back to The 56th Southeast Regional Meeting 2004 (November 10-13, 2004)