The Chemistry Department Presents: Enhancing the dimensionality of lipidomics analyses for studies of antibiotic resistance

The analysis of lipids by mass spectrometry is challenged by the large
number of unique lipid species that occur in a narrow range of mass-to-charge
(m/z) from 600-900 Da. To enable the detection and accurate identification
of lipids, it is necessary to increase the dimensionality of lipidomics
experiments by pairing MS with separation techniques such as liquid chromatography. Ion mobility-mass spectrometry (IM-MS) is a rapid gas-
phase separation technique based on structure and mass that is orthogonal to conventional liquid chromatography techniques. In this talk, I will describe
our efforts to develop a method for untargeted lipidomics that combines hydrophilic interaction
liquid chromatography (HILIC) with IM-MS that provides detailed molecular information in the
form of lipid class, collision cross-section, accurate mass, and fragmentation pattern to support
identification of unknown lipid species. The merits of the HILIC-IM-MS approach relative to
conventional techniques will be demonstrated for the study of altered membrane composition in
several species of Gram-positive bacteria with resistance to the lipopeptide antibiotic,
daptomycin.

BIO Dr. Kelly Hines received her Bachelor of Science in Chemistry from the University of
Florida in 2009 and completed her PhD in 2014 in the lab of John A. McLean at Vanderbilt
University. Dr. Hines’ graduate research focused on the use of ion mobility-mass spectrometry
(IM-MS) to characterize biological systems including cancer and wound healing. After
graduating from Vanderbilt, Dr. Hines completed a one-year postdoc with the Mayo Clinic
Metabolomics Resource Core where she developed quantitative mass spectrometry methods for
lipids and small molecules. Dr. Hines joined the Xu Lab in July 2015 and her current research
centers on the development and use of IM-MS for lipidomics analyses.

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