Gas-phase ion mobility studies of constitutional isomeric hydrocarbons using different ionization techniques

We have investigated the influence of structural differences on the ionizat ion pathways and drift behavior in ion mobility spectrometry for constituti onal isomeric hydrocarbons. The ion mobility spectra of isomeric alkylated benzenes (C9H12 and C10H14) were recorded using photoionization, Ni-63 ioni zation and corona discharge ionization. Defined spectra for almost all isom eric compounds were observed using photoionization. When using this techniq ue, no differences in ion mobility spectra of isomers can be observed. Howe ver, the methods of atmospheric-pressure chemical ionization (Ni-63 and cor ona discharge ionization) produce differences in ion mobility spectra or in the detectable concentration ranges of isomeric compounds depending on the number and position of aliphatic side chains. (C) 2001 Elsevier Science B. V.