ABSTRACT
Chapters 1 and 2 introduced the various processes (ionization and fragmentation) that occur in the mass spectrometer and the means by which they can be used for reconstructing a molecular structure from the observed fragments. The nominal molecular weight and masses of fragment ions, when supplemented by other spectroscopic information, can often lead to the solution of an organic structure problem. One must, however, rely on making the correct assumptions concerning the compositions of the various ions. In many cases, these assumptions are quite straightforward. For example, a hydrocarbon that lacks strong absorption in the ultraviolet (UV) band and has a molecular weight of 182 must have an elemental composition of C13H26 (one ring or double bond). The alternative C14H14 composition would be easily recognized in the mass spectrometer as either a polyene or polycyclic compound and would probably be UV absorbing.
