Fragment Ion Produced by EI

70eV-electrons, normally used in EI, have enough energy to break up compounds. We call this decomposition of a molecule "fragmentation". Generally speaking, the molecular ion M+* in a vibration state is first produced, then the fragment ion m+ is produced from this unstable molecular ion because of excess energy in M+*.

Chemical bonds usually break at weak bonds. Analysis of fragment spectra provides us with information on the chemical structures of a compound.

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