Principal Research Interests
We advance the technology and new applications of ion mobility separations (IMS), mainly in conjunction with mass spectrometry. The major focus is on novel nonlinear approaches of differential or field asymmetric waveform IMS (FAIMS) that leverage the dependence of ion transport properties in gases on the electric field strength.
Our lab employs custom planar FAIMS systems with highest resolving power ever achieved - up to ~500 for multiply charged ions. This performance has allowed previously unthinkable analyses, such as the baseline separations of PTM localization variants for modified peptides, individual protein conformers, regioisomers of lipids, and even isotopomers. We are working to increase the resolution yet further, to enable even more challenging separations. These efforts are pursued in tight collaborations with the instrument companies in the field.
To optimize IMS methods and extract the ion structures from measured cross sections, we are improving the first-principles methods for ion mobility calculations. Of particular interest is the new paradigm of Scattering on Electron Density Isosurfaces (SEDI), where ions are represented by electron clouds (numerically defined on a discrete grid) rather than atomic coordinates. The combination of SEDI with classical dynamics in the approximated ion-molecule potential is the most accurate approach to compute ion mobilities known today.
- A. A. Shvartsburg. Ultrahigh-Resolution Differential Ion Mobility Separations of Conformers for Proteins above 10 kDa - Onset of Dipole Alignment? Anal. Chem. 86, 10608 (2014).
- Y. Alexeev, D. G. Fedorov, A. A. Shvartsburg. Effective Ion Mobility Calculations for Macromolecules by Scattering off Electron Clouds. J. Phys. Chem. A 118, 6763 (2014).
- A. A. Shvartsburg, Y. Zheng, R. D. Smith, N. Kelleher. Ion Mobility Separations of Variant Histone Tails Extending to the Middle-Down Range. Anal. Chem. 84, 4271 (2012).
- A. A. Shvartsburg, R. D. Smith. Accelerated High-Resolution Differential Ion Mobility Separations Using Hydrogen. Anal. Chem. 83, 9159 (2011).
- A. A. Shvartsburg, D. E. Clemmer, R. D. Smith. Isotopic Effect on Ion Mobility and Separation of Isotopomers by High-Field Ion Mobility Spectrometry. Anal. Chem. 82, 8047 (2010).
- A. A. Shvartsburg, S. Y. Noskov, R. Purves, R. D. Smith. Pendular Proteins in Gases and New Avenues for Characterization of Macromolecules by Ion Mobility Spectrometry. Proc. Nat. Acad. Sci. USA 106, 6495 (2009).
- A. A. Shvartsburg, R. D. Smith. Fundamentals of Traveling Wave Ion Mobility Spectrometry. Anal. Chem. 80, 9689 (2008).
- A. A. Shvartsburg, F. Li, K. Tang, R. D. Smith. Characterizing the Structures and Folding of Free Proteins Using 2-D Gas-Phase Separations: Observation of Multiple Unfolded Conformers. Anal. Chem. 78, 3304 (2006).
- A. A. Shvartsburg, M. F. Jarrold. Solid Clusters Above the Bulk Melting Point. Phys. Rev. Lett. 85, 2530 (2000).
- K. M. Ho, A. A. Shvartsburg, B. Pan, Z. Y. Lu, C. Z. Wang, J. G. Wacker, J. L. Fye, M. F. Jarrold. Structures of Medium-Sized Silicon Clusters. Nature 392, 582 (1998).