The three-day course on Interpretation of Electron Ionization Mass Spectra can be considered as a basic starters course for people with some experience in GC-MS and wanting to get more insight in the interpretation of the mass spectra generated by electron ionization (EI). The course provides a solid understanding of the fragmentation of odd-electron ions, paying attention to both fragmentation mechanisms and practical issues related to compound identification, such as library searching. The approach in the treatment of fragmentation and interpretation is pragmatic rather than fundamental. A very important aspect of the course is solving a series of exercises to practice the interpretation rules.
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Session 2: Appearance of Mass Spectra.General principles of mass spectrometry are introduced. The module contains discussion on ionization techniques, quadrupole mass analysers, concepts of mass, and general aspects of data-acquisition and processing.
Session 3: General Fragmentation Rules.This session deals with the information that can be retrieved from a mass spectrum. Topics discussed are: average and monoisotopic mass, mass defects, double-bound equivalents, the nitrogen rule, isotope peaks, m/z-axis calibration.
Session 4 - 6: Important Fragmentation Reactions.After a discussion on some general aspects of electron ionization, this session deals with general aspects of fragmentation of odd-electron ions and mass-spectral interpretation: recognition and stability of the molecular ion, types of fragmentation reactions, charge localization, stability of product ions, and Stevenson's rule
Session 7 - 8: General Interpretation Strategies.In the next three sessions, important fragmentation reactions are discussed in detail and illustrated with examples: the sigma-cleavage, the homolytic cleavage, the heterolytic cleavage, the McLafferty rearrangement, the retro-Diels-Alder fragmentation and other fragmentation reactions with cyclic compounds. Attention is also paid to important secondary fragmentation reactions of even-electron fragment ions.
Session 9 - 10: Mass Spectra of Various Compound Classes.After a practical summary of the fragmentation reactions, this session deals with general interpretation strategies. Ion series are introduced, as well as the use of tables with common neutral losses and common low-mass fragment ions. Like in previous session, important issues are trained with ample interpretation examples and exercises. The second part of this part pays attention to library searching, illustrated with examples which enable a critical evaluation of the power and limitations of automated library searching.
Optional: Session 11-12: Developments in Mass SpectrometryThe occurrence of the fragmentation reactions discussed are illustrated in mass spectra of various compound classes. In this part of the course, special attention can be paid to the mass spectra of specific compound classes important to your own laboratory and/or application area.
While discussion on other compound classes can be extended to the final part of the course, often there is interest in learning about other developments in mass spectrometry. This can be GC-MS related topics, e.g., derivatization and its effect on mass spectra, chemical ionization. However, this course frequently contains a discussion and overview on the potential and limitation of combined liquid chromatography-mass spectrometry (LC-MS) and or tandem mass spectrometry (MS-MS).