Niessen W. Interpretation of MS-MS mass spectra of drugs and pesticides

Wiley SERIES ON MASS SPECTROMETRY — John Wiley & Sons, Inc,, 2017. — 393 pagesIn the 1980s, tandem mass spectrometry was introduced for the structural elucidation of even-electron ions (protonated or deprotonated molecules) generated by soft ionization techniques such as fast-atom bombardment, thermospray, and electrospray. When compared to the fragmentation of odd-electron ions generated by electron ionization, scientists were well aware of the fact that different rules apply to the fragmentation of even-electron ions. Surprisingly, no major fundamental research was carried out on trying to understand and describe these differences. More effort was placed on the development of improved instrumentation and advanced applications for emerging technologies.This particular effort paid off, as exemplified by tandem mass spectrometry which, often in combination with gas or liquid chromatography, has been a major contributor to the progress of many scientific disciplines, for example, pharmaceutical, biochemical, and environmental sciences;
food safety; sports doping analysis; clinical diagnostics; forensics; and toxicology.This work is an attempt to add to the understanding of the fragmentation of even-electron ions. This has been done by studying the fragmentation of a wide variety of compounds, with a special focus on chemical structure similarities, that is, from the same class. The basic data set used comprises several mass spectral libraries developed for general unknown screening in toxicology. In this respect, we need to thank Dr Wolfgang Weinmann (originally at the Institute of Legal Medicine, University of Freiburg, Germany, and currently at the Institute of Forensic Medicine, University of Bern, Switzerland) for providing public access to his toxicology library and the library of designer drugs via the Internet (http://www.chemicalsoft.de/index.html); DrPierre Marquet (of the Faculty of Medicine, Department of Pharmacology, Toxicology, and Pharmacovigilance at the University Hospital of Limoges, France) for providing his mass spectral library of negative-ion mass spectra; and Dr.BernhardWüst of Agilent Technologies for his help with using the Agilent Broecker, Herre & Pragst PCDL for forensic toxicology. The information from these libraries and other data sets is complemented by data from the scientific literature.The origins of this book can be found in two publications describing the fragmentation of toxicologically relevant drugs in both positive-ion tandem mass spectrometry (Niessen, 2011) and negative-ion tandem mass spectrometry (Niessen, 2012). Soon after, the authors decided to develop the project further by extending the number of compounds covered and the detail of the information provided. The fragmentation of some 1300 compounds and the product-ion mass spectra of even more are studied and interpreted in this book.This volume consists of five chapters. Chapters 3 and 4 are the main chapters, where proposed fragmentation rules for the “Fragmentation of Even-Electron Ions” (Chapter 3) are derived from the behavior of the “Fragmentation of Drugs and Pesticides” (Chapter 4) pertaining to many different classes of compounds. Chapter 1, “Introduction to LC – MS – MS Technology”, provides a concise introduction to mass spectrometry technology. Chapter 2, “Interpretation of Mass Spectra” gives the basic concepts and definitions related to the information that can be extracted from mass spectra. Finally, Chapter 5, “Identification Strategies” gives an overview of the different classes of unknowns and identification strategies that exist as well as how they relate to multiple areas of application.Last but not least, special thanks go to our families and the many people who have inspired us to continue working on this project. We hope that you, as our reader, find this material useful and inspirational to further extend our understanding of the fragmentation of even-electron ions in tandem mass spectrometry.Introduction to LC-MS TechnologyAnalyte Ionization: Ion Sources
Electron Ionization
Chemical Ionization
Atmospheric-Pressure Ionization
Other Ionization Techniques
Mass Spectrometer Building Blocks
Tandem Mass Spectrometry
Data Acquisition
Selected Literature on Mass Spectrometry
Interpretation of Mass Spectra
Fragmentation of Even-Electron Ions
Fragmentation of Protonated Molecules
Characteristic Positive-ion Fragmentation of Functional Groups
Fragmentation of Deprotonated Molecules
Fragmentation of Metal-ion Cationized Molecules
Generation of Odd-electron Ions in ESI-MS, APCI-MS, and APPI-MS
Useful Tables
Fragmentation of Drugs and Pesticides
Fragmentation of Drugs for Cardiovascular Diseases and Hypertension
Fragmentation of Psychotropic or Psychoactive Drugs
Fragmentation of Analgesic, Antipyretic, and Anti-Inflammatory Drugs
Fragmentation of Drugs Related to Digestion and the Gastrointestinal Tract
Fragmentation of Other Classes of Drugs
Fragmentation of Steroids
Fragmentation of Drugs of Abuse
Fragmentation of Antimicrobial Compounds
Fragmentation of Antimycotic and Antifungal Compounds
Fragmentation of Other Antibiotic Compounds
Fragnmentation of Pesticides
Identification Strategies
Identification of Known Unknowns and Real Unknowns
Compound Index 381
Subject Index 389