Product Support Bulletin 102
The resonance excitation process used for MSn in an ion trap device fragments only the selected ion. Fragment ions formed in this manner do not themselves undergo subsequent fragmentation, as is the case in the collision cell of a triple quadrupole or QqToF mass spectrometer. This has obvious benefit because fragmentation pathways are significantly easier to follow using an ion trap device. Hydroxylated compounds, however, frequently show only the loss of H2O in the first stage of MSn analysis. In this situation, an additional stage of MS would be required to generate more structurally useful information.
Thermo Fisher Scientific