Comparison of Mass Spectral Characteristics Using Statistical Analysis Methods for the Case of Electron Ionization of Organic Molecules at Different Electron Energies.

The sensitivity and accuracy of identifying volatile organic compounds using mass spectrometric gas analyzers operation in the electron ionization mode can be enhanced by increasing the number of ions formed in the ion source by varying the energy of ionizing electrons. The paper presents a comparison of data obtained by electron impact ionization at electron energy (EE) in the range of 25–105 eV for a number of organic substances belonging to different classes of organic compounds. an analysis using similarity matrices based on various similarity metrics was performed to interpret the dynamics of changes in the intensities of fragment ion peaks, and the influence of EE on the formation probability of the main fragment species of the substances under study and, accordingly, on the resemblance of a recorded mass spectrum to the reference mass spectrum from the database was shown. [ABSTRACT FROM AUTHOR]