Abstract
In-beam electron ionization (EI) and mass analyzed ion kinetic energy (MIKE) spectrometric techniques were used to study the EI-induced fragmentation of choline iodide, choline chloride, hexadecyltrimethylammonium bromide, ethylhexadecyldimethylammonium bromide, and methyltricaprylammonium chloride. The in-beam EI and MIKE spectra of these compounds are presented. The in-beam EI spectra exhibit intact quaternary ammonium cations as well as thermally and EI-induced fragment ions. The fragmentation pathways arising from the intact cations in the in-beam EI spectra were defined by using the MIKE technique. The general fragmentation processes are similar to those of simple tetraalkylammonium cations previously reported. The inbeam EI spectra of a sample of tricaprylmethylammonium chloride exhibit abundant ions that are due to lower and higher homologous cations, indicating that the sample is a mixture of at least three homologs.
