Interpretation Of Mass SpectraMolecular mass spectrometry continues to show an exponential growth, with a substantial proportion of its applications still requiring the identification of unknown mass spectra. The first edition of this book was published more than 25 years ago, when most instruments could measure only a few unknown mass spectra per hour. The most important addition to this book, in the opinion of the senior author, is its co-author, Frank Turecek. He has made especially important contributions to the mechanisms in Chapters 7-9, representing more than one-third of the book. The extensive revisions by the authors have had the objective of correlating ion dissociation mechanisms on a much broader scale, with emphasis on basic attributes such as ionization energies, proton affinities, and bond-dissociation energies. The authors also attempted to show how these mechanisms are applicable to the unimolecular dissociations of ions formed by any ionization method, including the exciting variety of new methods for obtaining mass spectra of large molecules. |
Contents
Introduction | 1 |
2 Elemental Composition | 19 |
3 The Molecular | 35 |
Basic Mechanisms of lon Fragmentation | 51 |
5 Postulation of Molecular Structures | 85 |
Auxiliary Techniques | 103 |
Theory of Unimolecular lon Decompositions | 115 |
Common terms and phrases
100 Relative intensity a-cleavage ABCD acids alcohols alkanes alkenes alkyl group allylic amines aromatic base peak C₂H carbon atoms CH₂ charge migration charge retention Chem cleavage CnH2n+1 competitive compounds contain corresponding cyclic dissociation double bond EE+ ions electronegative elemental composition elimination Equation esters ether even-electron ion example favored Figure formation formed fragment ions functional groups H₂C H₂O heteroatom hydrogen hydrogen atoms hydrogen rearrangement important indicates intensity 100 internal energy ion series ion-molecule ionization energy isomerization isomers isotopic ketones loss m/z Int Mass Spectrometry mass spectrum mass units McLafferty methyl molecular ion molecular weight molecule neutral OCH3 odd-electron ion oxygen pathways peak at m/z phenyl possible product ion proton affinity radical radical ion reactions rearrangement reactions Relative intensity 50 ring sample Section specific spectra stability steric structure substitution Table A.3 tion Tureček Unknown unpaired electron unsaturated yield