Common Mass Losses on Fragmentation

When a molecule ionizes, it follows the reaction M + e - M+ + e + e , as described earlier. When an OE molecular ion fragments, it can do so in a variety of ways, and resulting OE fragment ions can also fragment in similar ways. Simple cleavage results in the expulsion of a neutral fragment that is an OE radical (OE ) and formation of an EE ion (EE+) as shown in the following  

Multicentered fragmentation results in the expulsion of an EE neutral species and formation of an OE ion (OE+ )  

In the first case, we would detect the EE+ ion and, in the second case, the OE+ ion. The neutral species lost on fragmentation can be identified by the difference between the mass of M+ and the fragment ion. Common losses from the molecular ion are given in Table 10.9. Tables 10.10 and 10.11 list more common neutral fragments expelled by simple cleavage and by multicentered fragmentations. 

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