Utilizing a ReTOF for Tandem MS

Consider an ion mi decomposing in transit through a field-free region. Its kinetic energy is distributed among the product ion m2 and the neutral fragment n according to their relative contribution to the mass of the precursor ion 

Despite the comparatively poor precursor ion resolution and being a time- and sample-consuming procedure, in comparison to the later true tandem TOF instruments, MS/MS of post-source decay (PSD) ions on the ReTOF had become established as one of the major tools of biomolecule sequencing for ions in the tn/z 500-3000 range. 

In particular the MALDI-TOF community has coined some sort of own terminology, e.g., in-source decay (ISD) for all fragmentations occurring within the ion source, post-source decay (PSD) instead of metastable ion dissociation, and fragment analysis and structural TOF (FAST) for the specific mode of operation of a ReTOF to detect metastable ions. 

Note Methods for the detection of metastable ion dissociations in ReTOF-MS in combination with secondary ion mass spectrometry (SIMS) and plasma desorption ( Cf-PD) mass spectrometry were known before the advent of MALDI [41-44], 

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