Isotopic labelling in mass spectrometry as a tool for studying reaction mechanisms of ion dissociations

Abstract Perhaps the greatest influence that isotopic labelling experiments have had on organic mass spectrometry is that reaction mechanisms originally borrowed from the chemistry of neutral counterparts have proved to be inadequate for explaining the results. It was therefore necessary to devise completely new types of fragmentation mechanisms and unconventional structures for organic gas‐phase cations. In most cases the labelling technique …