Studies of consecutive reactions of organic ions in a reversed geometry mass spectrometer

Over thirty consecutive reactions of a type m 1 + → m 2 + → m 3 + have been studied in a variety of organic compounds using a reversed geometry mass spectrometer. Two field free regions allow the separation of the two steps that make up the consecutive reaction sequence. Translational energy release measurements are used in the comparison of m 2 + ions formed as a result of a high energy process in the ion source with m 2 + ions formed as a product of a metastable decomposition. In some cases the structures of such ions have been found to be different. Examples have also been found where consecutive fragmentations of metastable ions do not occur although, when higher energy ions within the source are studied, the two‐step reaction does take place. Furthermore, it has been found that a control over ion internal energy may be achieved by selecting portions of a peak due to the fragmentation of a metastable ion. Unimolecular reactions may then be used to study the reactivity of such ‘energy‐selected’ ions; collision induced reactions can be used to study the structure of both the reactive and unreactive energy selected ions.