Ion Mobility Spectrometry: Fundamental Concepts, Instrumentation, Applications, and the Road Ahead

TLDR

Ion mobility spectrometry is a rapid, millisecond‑scale separation technique that has grown rapidly and is increasingly coupled to mass spectrometry for multidimensional analysis, yet the proliferation of new IMS platforms has caused confusion about their relative advantages. This review aims to clarify common misconceptions about the fundamental concepts and strengths and weaknesses of the main IMS platforms (DTIMS, TWIMS, TIMS, FAIMS, DMA) for new users. The authors discuss common IMS‑MS applications, including isomer separation, MS signal filtering, and the use of collision cross‑section values as ion descriptors in targeted and untargeted omics workflows. Despite remaining challenges, the authors conclude that IMS holds bright prospects for routine mobility data collection in the future.

Abstract

Ion mobility spectrometry (IMS) is a rapid separation technique that has experienced exponential growth as a field of study. Interfacing IMS with mass spectrometry (IMS-MS) provides additional analytical power as complementary separations from each technique enable multidimensional characterization of detected analytes. IMS separations occur on a millisecond timescale, and therefore can be readily nested into traditional GC and LC/MS workflows. However, the continual development of novel IMS methods has generated some level of confusion regarding the advantages and disadvantages of each. In this critical insight, we aim to clarify some common misconceptions for new users in the community pertaining to the fundamental concepts of the various IMS instrumental platforms (i.e., DTIMS, TWIMS, TIMS, FAIMS, and DMA), while addressing the strengths and shortcomings associated with each. Common IMS-MS applications are also discussed in this review, such as separating isomeric species, performing signal filtering for MS, and incorporating collision cross-section (CCS) values into both targeted and untargeted omics-based workflows as additional ion descriptors for chemical annotation. Although many challenges must be addressed by the IMS community before mobility information is collected in a routine fashion, the future is bright with possibilities.