Mass spectral fragmentation alkanes

How did our understanding of the mass spectral fragmentations of alkanes improve with this revolution of the instrumental capacities One has to take note that most of these improvements went into an enlargement of the number of classes of substances that could be measured with these instruments, the hydrocarbons having become somewhat the poor parent of mass spectrometry, the fragments containing two to four carbon atoms forming a notable exception because of their widespread abundance in all mass spectra and the possibility to make ab initio or semi-empirical calculations of new, hitherto unknown structures. 

The correct analysis of the homologous ion series has certain limitations. Low abundances of peaks in some series require the attention and experience of a researcher. Usually alkane series are dominated in the mass spectra of the most various compounds. Fragmentation initiated by one functional group may completely suppress or notably camouflage other reactions of polyfunctional substances. In the latter case it is useful to consider IR-spectroscopy data in mass spectral interpretation. 

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