| AVS 58th Annual International Symposium and Exhibition | |
| Vacuum Technology Division | Monday Sessions |
| Session VT-MoA |
| Session: | Optical and Mass Spectroscopy for Gas Analysis and Pump Modeling |
| Presenter: | Steven Thornberg, Sandia National Laboratories |
| Authors: | S.M. Thornberg, Sandia National Laboratories J.M. Hochrein, Sandia National Laboratories M.I. White, Sandia National Laboratories |
| Correspondent: | Click to Email |
Hydrogen getters are used in many industries including aerospace, defense, and electronics (e.g., MEMS packaging) to control levels of hydrogen in sealed atmospheres and vacuum systems. In this research, we explore not only the products formed during the hydrogenation process but also the product distribution resulting from differing rates of hydrogenation. This work focuses on the analysis of hydrogenation products of 1,4-bis(phenethyl)benzene (DEB) using GC/MS and a method for creating samples with known hydrogenation levels. This information can then be used to calculate the remaining capacity of the getter by determining the ratios of saturated, partially saturated, and unsaturated products.
DEB has a molecular formula of C22H14 (MW=278 amu) and has a capacity for four moles molecular hydrogen per mole of DEB. The analysis of pure DEB (unhydrogenated) showed no contamination from partially hydrogenated products and only one chromatographic peak (from DEB). As hydrogenation proceeds, a series of products is formed with nominal masses 280, 282, 284, and 286 amu (282, 286, 290 and 294 amu for deuterium). Hydrogenation experiments were performed from 0% to 100% hydrogenation (calculated by molar ratios) with hydrogen mixed with a buffer gas (nitrogen) to slow the uptake reaction rate. After hydrogenation, the resultant solid was homogenized, dissolved in methylene chloride, and filtered. The stock solutions, diluted appropriately, were then analyzed using gas chromatography (Agilent, model 6890N) for product separation, and a high-resolution mass spectrometer (Jeol MStation, model JMS-700) for product identification.
In this talk, a comparison between the GC/MS method presented here and the traditional CHN analysis method will be presented. Round robin samples between three labs were used to assess the performance of each method.
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear Security Administration under Contract DE-AC04-94AL85000.