Gas-phase ion mobility studies of amines and polyether/amine complexes using tandem quadrupole ion trap/ion mobility spectrometry

The gas-phase positive ion mobility spectra of isomeric amines and polyether/amine complexes have been measured using a tandem quadrupole ion trap/ion mobility spectrometer. Ion mobilities of isomeric amines in helium, determined relative to benzene at pressures in the range 1-2 Torr, vary with the structure of the amine. The ability of quadrupole ion trap/ion mobility spectrometry to differentiate between a pharmacologically-active substance and an associated isomeric amine is demonstrated. Non-covalent complexes of cyclic and acyclic polyethers with protonated amines were generated by ion/molecule reactions in the ion trap and analysed by ion mobility spectrometry. The ion mobilities in helium may be interpreted in terms of the preferred conformations for these complexes. The use of polyether hosts as shift compounds for enhancing the relative mobilities of small amine guest ions is proposed.