Scott R. Bryan oral presentation (OA3-Tue2-3-6)
Applications of TOF-SIMS MS/MS for Industrial Problem Solving
Physical Electronics, 18725 Lake Drive East, MN 55317 Chanhassen, United States
One of the most important analytical capabilities for an industrial central analytical lab is the ability to analyze and identify unknown compounds. One of the most common requests is to distinguish between “good” and “bad” samples of supposedly the same composition. For failure analysis labs, the goal is often to determine the source of contamination or defects in a production process with poor yield. Other applications are to identify contamination left behind from different cleaning procedures or after use. In all these circumstances, one does not know ahead of time what chemical compounds are present. TOF-SIMS is an ideal technique for these applications because it has high sensitivity, high specificity, and parallel detection of all masses. One complication is that real-world samples usually have a complex mixture of compounds on the surface, making the TOF-SIMS spectrum difficult to interpret. Further, the use of a wide variety of different primary ion beams (e.g. Ga+, In+, Au+, Bi+, C60+, and Arn+) has complicated the use of TOF-SIMS spectral databases for compound identification due to large changes in relative peak intensities from one beam to another.
A MS/MS capability was recently integrated into a TOF-SIMS instrument to make peak identification easier [1,2]. It allows unambiguous identification of both organic and inorganic peaks above m/z 200, where the mass accuracy is insufficient to identify the composition of a peak by its exact mass. A MS/MS spectrum from a single precursor mass is much easier to match using a spectral database compared to using the original complex TOF-SIMS spectrum. In addition, the MS/MS spectrum of a given precursor ion is independent of the primary ion used to generated it. Even MS/MS databases using other sources, such as electrospray, have been found to be very useful for TOF-SIMS MS/MS spectral matching.
Several case studies will be given where MS/MS was needed to identify compounds from an analysis of industrial samples. Two modes of MS/MS will be compared and contrasted. One is based on collision induced dissociation (CID) with inert gas and the other is based on post source decay (PSD).
 G.L. Fisher, J.S. Hammond, P.E. Larson, S.R. Bryan, R.M.A. Heeren, J. Vac. Sci. Technol. B 34(3), 2016, 03H126-1.
 G.L. Fisher, A.L. Bruinen, N. Ogrinc Potočnik, J.S. Hammond, S.R. Bryan, P.E. Larson, R.M.A. Heeren, Anal. Chem., 88, 2016, 6433-6440.