Atmospheric pressure ion mobility spectrometry studies of cyclic and acyclic polyethers

Cyclic and acyclic polyethers have been analysed by atmospheric pressure ion mobility spectrometry (IMS). The reduced mobilities of gas-phase cyclic polyether ions may be distinguished from their acyclic analogues as a consequence of differences in the collision cross-sections of their adopted conformations. Peaks attributed to polyether/protonated amine complexes are formed when polyethers are introduced in the presence of Nethylmethylamine, n-propylamine and benzylamine vapour. Variations in the reduced mobilities for the polyether complexes containing isomeric N-ethylmethylamine and npropylamine guests are associated with small conformational differences for these ions. SYBYL(TM) molecular modelling software was used to confirm structural characteristics inferred from the experimental mobility data.