The Rise of Trapped Ion Mobility Spectrometry: Principles, Applications, and Recent Developments

Trapped ion mobility spectrometry (TIMS) is a highly versatile alternative to the more conventional drift tube ion mobility spectrometer (DTIMS). In TIMS, ions are analyzed using an electric field that holds ions stationary against moving gas. In the basic TIMS, ions are accumulated and trapped in the electric field and then eluted over time according to their collision cross section (CCS) as the strength of the electric field is scanned down. The resultant small size and low operating voltage of TIMS compared to prior approaches make it ideal for hybridization with mass spectrometry. Since its introduction and coupling with Time-of-Flight Mass Spectrometry (TOFMS) in 2011, TIMS has been widely and successfully applied in various bioanalytical fields, including proteomics, glycomics, metabolomics, lipidomics, and native mass spectrometry. In particular, the first commercial TIMS-MS instrument introduced by Bruker Daltonics Inc. (timsTOF), launched in 2016, quickly shined as one of the main reference instruments in bottom-up proteomics. The increased peak capacity, resulting from the additional dimension of separation-that is, mobility-leads to mass spectra of reduced complexity and a greater depth of peptide identification. In this retrospective, different designs and operational modes of TIMS will be presented with a focus on the advantages, potentials and challenges of this technology within the fields of the omics sciences, spanning from metabolomics to structural biology, including single cell analysis. Additionally, the newest platforms utilizing TIMS technology will be introduced, with a focus on future applications and direction of the technology.