Ion/molecule reactions of o-carborane(12) and a method for identifying overlapped isotopic distributions in complex mass spectra

A high resolution Fourier transform ion cyclotron resonance mass spectromet er was used to investigate gas phase ion/molecule reactions of o-carborane( 12) (-C2B10H12). The reaction of o-carborane(12) neutrals and cations produ ced oligomeric carborane species. Extensive hydrogen losses and H2O/CH3OH a dducts were also observed and these resulted in complex mass spectra contai ning overlapped isotopic distributions. For a cell pressure of 6.0 x 10(-9) mbar and for reaction delays from 50 ms to 30 s, some 73 species were iden tified in the resultant mass spectra, and their reaction kinetics were expl ored using a simplified, six step reaction mechanism. The analysis of these complex mass spectra was simplified by MACLOOMIS, an interactive program b ased on pattern recognition techniques originally developed for the analysi s of high resolution vibration-rotation spectra. When adapted to mass spect ra, MACLOOMIS enabled the rapid identification of overlapped isotopic distr ibutions, and this approach may prove useful for a wide range of mass spect rometry studies. (Int J Mass Spectrom 202 (2000) 37-45) (C) 2000 Elsevier S cience B.V.