INRAE 1 article published in JoVE Chemistry Using a Cyclic Ion Mobility Spectrometer for Tandem Ion Mobility Experiments Simon Ollivier1,2, Mathieu Fanuel1,2, Hélène Rogniaux1,2, David Ropartz1,2 1INRAE, UR BIA, F-44316 Nantes, France, 2INRAE, BIBS Facility, F-44316 Nantes, France Ion mobility spectrometry (IMS) is an interesting complement to mass spectrometry for the characterization of biomolecules, notably because it is sensitive to isomerism. This protocol describes a tandem IMS (IMS/IMS) experiment, which allows the isolation of a molecule and the generation of the mobility profiles of its fragments.