Libin Xu, PhD
Department of Medicinal Chemistry
University of Washington

Hosted by Lingjun Li

Enhancing the Throughput and Confidence of Drug and Lipid Identification by Ion Mobility-Mass Spectrometry

Abstract
Small molecule drugs mostly have molecular weight of less than 500, but they exert large structural diversity as they bind to various drug targets. Drug metabolism by Phase-I and Phase-II enzymes further increases such structural diversity. Similarly, most lipid species occupy a narrow mass range of 600 – 900 although they are distinct by their headgroups and fatty acid compositions. The large number of molecules in a small mass range results in large number of ions with the same masses in mass spectrometry analysis, which presents a challenge for their resolution by mass spectrometry alone. Such challenge can be addressed by ion mobility-mass spectrometry (IM-MS), which can increase the throughput and confidence of identification of these molecules. IM rapidly separates ions based on their apparent gas-phase surface areas, i.e., collision cross sections with a neutral buffer gas, a physical property that is characteristic to a particular ion. In this talk, I will discuss the application of IM-MS in the analysis of drug and drug metabolites, as well as in characterizing lipidomic changes in Gram-positive pathogens after developing resistance to cell envelope-active antimicrobials.