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 N-ethylmethylamine, n-propylamine and benzylamine vapour. Variations in the reduced mobilities for the polyether complexes containing isomeric N-ethylmethylamine and n-propylamine 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. (C) 2001 Elsevier Science B.V. All rights reserved.