Ion mobility spectrometry: a review. Part 1. Structural analysis by mobility measurement

Ion mobility spectrometry (IMS) is an electrophoretic technique that allows ionised analyte molecules to be separated on the basis of their mobilities in the gas phase. The technique has found widespread application as a detector, most noticeably for chemical warfare agents on the battlefield and for explosives and narcotics at ports and airports. The application of IMS to structural studies of small molecules has also been recognised since the advent of the technique in the 1970s. The coupling of IMS with electrospray (ESI) and MALDI ion sources has opened up exciting possibilities for the study of the conformations and structures of a wide range of biomolecules in the gas-phase, including proteins, peptides and oligonucletoides. This tutorial review discusses the principles, instrumentation and applications of IMS for the elucidation of molecular structural characteristics.