Electron-capture dissociation (ECD) is a new fragmentation technique that utilizes ion–electron recombination reactions. The latter have parallels in other research fields; revealing these parallels helps to understand the ECD mechanism. An overview is given of ECD-related phenomena and of the history of ECD discovery and development. Current views on the ECD mechanism are discussed using both published and new examples.

Keywords: electron capture dissociation, ion–electron reactions, fragmentation, peptides and proteins