Recent advances in differentiation of isomers by ion mobility mass spectrometry

Differentiation of isomers is an important analytical task in many fields, e.g., chemistry, biology, pharmaceutical science, medicine, environmental science, food science. Ion mobility mass spectrometry (IM-MS) can resolve isobaric ions based on their shape and size and measure the collision cross section (CCS) values of ions to provide information on their intrinsic structures, and is thus a very promising tool for differentiation of isomers. In this review, the applications of IM-MS in differentiation of various isomers including glycans, lipids, amino acids, peptides, proteins, as well as metabolite isomers, chiral isomers, etc. are summarized. Prospects for further development of IM-MS for differentiation of isomers, e.g., improved resolving powers of IM-MS instruments and measurement reproducibility, expanded CCS database and coupling of IM-MS with computational approaches, are also discussed.