6.11.2 Fragmentation of Cyclic Ketones
Cyclic ketones major cleavage is also at the α bond. Due to the ring structure, this cleavage will be detected as the molecular ion unless another bond is broken. Saturated cyclic ketones produce a fragment at m/z 55 illustrated by cyclohexanone.
In cyclohexanone, this peak is the base peak. In absence of a reference standard, cyclic ketones are difficult to identify given the difficulty explained earlier in determining the composition of the alkyl portion of the ketone.
©Dunnivant & Ginsbach, 2008