Royal B. Freas

The role of cluster ion structure in reactivity and collision‐induced dissociation: Application to cobalt/oxygen cluster ions in the gas phase

Ion/molecule reaction products of cobalt cluster ions have been characterized using mass spectrometric techniques. Atomic and bare‐metal cluster ions were desorbed from foils by particle bombardment within a high‐pressure (0.1–0.2 Torr) ion source. Sputtered metal cluster ions react with O2 to produce abundant stoichiometric or nearly stoichiometric cobalt(II) oxide cluster ions. The positive cluster product ions consist of three types: oxygen‐deficient [Co(CoO)x]+ clusters, oxygen‐equivalent [(CoO)x]+ clusters, and (in less abundance) metal‐deficient [(CoO)xO]+ clusters. Tandem mass spectrometry and collision spectroscopy provide structural information about the more abundant cobalt cluster product ions. A major collision‐induced fragmentation pathway for the oxygen‐equivalent [(CoO)x]+ clusters is the loss of a CoO moiety to form [(CoO)x−1]+ fragments. A major collision‐induced fragmentation pathway for the oxygen‐deficient [Co(CoO)x]+ clusters is the loss of a cobalt atom to yield [(CoO)x]+ fragments. ...

Chemical ionization–fast-atom bombardment mass spectrometry: a novel ionization method

Chemical ionization reactions have been used with fast-atom bombardment mass spectrometry technique to post-ionize desorbed neutral species by proton transfer, charge exchange, and association reactions in order to enhance molecular parent ions.

Advanced Mass Spectrometry of Lubricants

Several developments have been made in mass spectrometry during the last few years. One of the most significant developments, fast-atom bombardment mass spectrometry, has tremendous potential for the characterization of lubricants. The technique is described, and examples of its use for the direct, rapid, and semiquantitative characterization of synthetic base oils and additives in lubricants are given. Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985