Ion Mobility Separation Using a Dual-LIT Miniature Mass Spectrometer

Ion mobility (IM) has been increasingly used in combination with mass spectrometry (MS) for chemical and biological analysis. While implementation of IM with MS usually requires complex instrumentation with delicate controls, in this study we explored the potential of performing IM separation using dual-linear ion traps (LITs) in a miniature mass spectrometer, which was originally developed for performing comprehensive MS/MS scan functions with a simple instrumentation configuration. The IM separation was achieved by ion transfer between the LITs with dynamic gas flow. Its performance was characterized for analysis of a broad range of chemical and biological compounds including small organic compounds such as trisaccharides, raffinose, cellotriose, and melezitose, as well as protein conformers. The demonstrated technique serves as another example of developing powerful hybrid instrument functions with simple configurations and miniaturized sizes.

This is a trial of using mass analyzers in a miniature mass spectrometer to achieve IM separation and measurement. Although high-resolution separation would need further development, the current demonstration of effectiveness shows its promising features for implementing the IM-MS for future applications using fieldable point-of-care instruments. The significance of this work is 2-fold; first, LITs are important components in designing a high-performance hybrid instrument as well as for portable instruments. The current dual-LIT configuration has been previously demonstrated for comprehensive tandem MS functions. Second, without adding additional components, the IMS separation is now implemented which has an implication on the future design of simple or small instruments for complex analysis. This would add a second dimension for achieving high selectivity in complex mixture analysis while using portable instruments of small sizes and simple configurations.