ALUMATRANE REVISITED - DISTRIBUTION OF OLIGOMERIC IONS IN ELECTRON-IMPACT IONIZATION, CHEMICAL-IONIZATION AND LIQUID SECONDARY-ION MASS-SPECTRA

Oligomeric ions formed from aluminium 2,2',2''-nitriltriethoxide (alum atrane) are present in electron impact (EI) ionization, chemical ioniz ation (CI), direct-exposure probe chemical ionization (DCI) and liquid secondary ion (LSI) mass spectra. These oligomeric ions are most pron ounced in the LSI mass spectrum, extending from monomeric to heptarner ic ions. The oligomeric ions exist there in the forms [M(n) + H](+) an d [M(n) + (AlO)(a) + (Al2O3)(b)](+) where the sum of a and b can be as high as 5. In contrast to previous interpretations of EI and CI resul ts, the LSI mass spectral data do not support a special stability for either the dimeric or tetrameric gas-phase forms of alumatrane.