Constantly, new rules are discovered that have to be added to the fragmentation rule databases.
The overall temporal fragmentation pattern of natural forests had a "perforation-subdivision/shrinkage-attrition" pathway, which corresponded to Forman's landscape fragmentation rule, while the plantation forests did not follow the rule strictly.
The most common fragmentation pathway likely results from the resonance stabilized anion conjugated to olefinic π clouds.
Common fragmentation ions were found between M1 and PBAlc, suggesting a similar backbone.
Rule-based fragmenters are based on fragmentation rules that were extracted from the MS literature over the years.
In contrast, rule-based prediction of fragmentation spectra (see Section "In silico fragmentation spectrum prediction") requires expert-curated "learning" of fragmentation rules.
The commercial software Mass Frontier [12] uses rule based fragmentation prediction based on standard reactions, a comprehensive library of over 100,000 fragmentation rules, or both.
In addition, we implemented fragmentation rules which reflect the (retro- synthetic access to these molecules.
A third commercial tool is MOLGEN-MS[196, 197] that uses general mass spectral fragmentation rules but can also accept additional fragmentation mechanisms.
For example, Gray et al[190] introduced CONGEN that predicts mass spectra of given molecular structures using general models of fragmentation, as well as class-specific fragmentation rules.
