Ion/neutral mass spectrometry of thermal ionizers: Application to ionization mechanisms from zeolites

Ion emission mechanisms from high temperature inorganic matrices are poorly understood, and pathways for sample loss are largely unknown. In an effort to gain better understanding of these processes, an instrument was designed, built and tested which measured in sequence the ions, and then the neutrals coming from the surface of high temperature matrices. Switching between modes was rapid enough to follow changes. This instrument was applied to the study of ion formation from potassium and silver zeolites. It was shown that the only form in which potassium sublimes from potassium zeolite is as monatomic cations. This helps to explain the high alkali metal ion formation efficiency observed from zeolite matrices and supports the concept that alkali metal ions are subliming directly from the solid state into the gas phase. In contrast, silver sublimes from silver zeolite as a combination of monatomic cations and neutrals, with the ion emission intensity about 3 orders of magnitude less than the emission of ions from alkali metal impurities.