Chapter 6. Electron Detachment Dissociation (EDD) and Negative Electron Transfer Dissociation (NETD)

Oligonucleotides, oligosaccharides, and proteins with acidic post-translational modifications (PTMs) are more effectively ionized in negative ion mode than as positive ions. Informative fragmentation data is required to determine the structural details for these sample types. Polarity insensitive activation methods such as collision-induced dissociation (CID) can be applied to both positive and negative ions, but often do not provide enough detail to fully characterize the structures of these molecules. Electron-based activation methods can provide data that is complementary to that produced by CID, and in many cases, more complete. These electron-based methods were developed principally for the characterization of positive ions but have great applicability to the dissociation of negative ions as well. Electron detachment dissociation (EDD) and negative electron transfer dissociation (NETD) are electron-based activation methods that have been developed for the analysis of multiply charged negative ions. This chapter presents a brief history of the evolution of the positive ion activation methods, electron capture dissociation (ECD) and electron transfer dissociation (ETD), into related methods for negative ions, namely EDD and NETD. A comprehensive description of EDD and NETD is presented, and their application to a variety of biologically relevant compound classes is reviewed.