Energy-resolved ion mobility-mass spectrometry--a concept to improve the separation of isomeric carbohydrates

J Am Soc Mass Spectrom. 2014 Mar;25(3):471-9. doi: 10.1007/s13361-013-0780-0. Epub 2014 Jan 3.

Abstract

Recent works using ion mobility-mass spectrometry (IM-MS) have highlighted the power of this instrumental configuration to tackle one of the greatest challenges in glycomics and glycoproteomics: the existence of isobaric isomers. For a successful separation of species with identical mass but different structure via IM-MS, it is crucial to have sufficient IM resolution. In commercially available IM-MS instruments, however, this resolution is limited by the design of the instrument and usually cannot be increased at-will without extensive modifications. Here, we present a systematic approach to improve the resolving capability of IM-MS instruments using so-called energy-resolved ion mobility-mass spectrometry. The technique utilizes the fact that individual components in an isobaric mixture fragment at considerably different energies when activated in the gas phase via collision-induced dissociation (CID). As a result, certain components can be suppressed selectively at increased CID activation energy. Using a mixture of four isobaric carbohydrates, we show that each of the individual sugars can be resolved and unambiguously identified even when their drift times differ by as little as 3%. However, the presented results also indicate that a certain difference in the gas-phase stability of the individual components is crucial for a successful separation via energy-resolved IM-MS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrates / chemistry*
  • Carbohydrates / isolation & purification*
  • Computational Biology
  • Isomerism
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Tandem Mass Spectrometry / methods*
  • User-Computer Interface

Substances

  • Carbohydrates