ION-MOLECULE-REACTION MASS-SPECTROMETER FOR ONLINE GAS-ANALYSIS

We describe an apparatus for ion-molecule-reaction mass spectrometry. It is suitable for on-line gas analysis covering the mass range from 1 to 200 amu with a sensitivity of about 1 ppm. The gas to be analyzed is ionized by reaction with a primary ion beam at low collision energy . A mass-selected ion source allows the fast switching among three pri mary ions beams (Xe+, Kr+, and CF3I+), covering the recombination ener gy range from 10.23 to 14.67 eV. Calibration measurements and an examp le of application to the study of heterogeneous catalysis are presente d. (C) 1998 American Vacuum Society.