We investigated the influence of structural differences on the ionization pathways and drift behavior in ion mobility spectrometry for cyclic and aliphatic hydrocarbons with different functional groups. The sets of cyclic and aliphatic compounds had an identical mass or a mass difference of 2 Da. Therefore, mass effects can be neglected during the investigation of these compounds. Depending on the functional group, considerable differences were found in the detectable concentration ranges and in the number and position of product ion peaks in ion mobility spectra. The spectra of chlorinated compounds and hydrocarbons show no correlation to their calculated collisional cross sections. Differences in collisional cross section between cyclic and aliphatic substances investigated were only found to influence the drift times detected for amines and aliphatic aldehydes while complex ion chemistry was observed for the other substances.
Ion mobility spectrometry (IMS)Atmospheric pressure ionization (API)