John McLean
Stevenson Professor of Chemistry
Senior Associate Dean for Research and Graduate Education, College of Arts and Science
Dr. McLean will be accepting graduate students for Fall 2025. The McLean group research activities center around the development and application of advanced mass spectrometry technologies for structural and molecular scale measurements, primarily via ion mobility-mass spectrometry (IM-MS). IM-MS is an integrated, two-dimensional analytical technique that provides rapid (µs-ms) separations based on molecular size and mass. Our focus is on using IM-MS with other analytical separation dimensions (e.g., liquid chromatography, LC; and tandem MS) to perform broad-scale, untargeted measurements of individual molecules derived from biological origins, inclusive of metabolites, carbohydrates, lipids, peptides and proteins. This multidimensional mass spectrometry approach provides a comprehensive inventory of the individual molecules present within a given sample, which can be further interrogated on a per-dimension level to obtain specific molecular information. For example, chemical hydrophobicity from LC, gas-phase size from IM; intrinsic mass from MS; and the connectivity of chemical bonds and function groups from tandem MS/MS. The elegance of this multidimensional MS approach is that all physiochemical properties can be obtained on a single measurement from microliters of sample, providing a basis for the rapid interrogation of large sample libraries to yield both a broad and deep chemical understanding at the systems biology level.
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Specializations
Analytical Bioanalytical Chemical Biology |
Representative Publications
Google scholar : https://scholar.google.com/citations?user=atieGE0AAAAJ&hl=en ORCID: https://orcid.org/0000-0001-8918-6419 |
Ellis B.M., Babele, P.K., May, J.C., Johnson, C.H., Pfleger, B.F., Young, J.D., McLean, J.A., Accelerating Strain Phenotyping with Desorption Electrospray Ionization-Imaging Mass Spectrometry and Untargeted Analysis of Intact Microbial Colonies, Proceedings of the National Academy of Sciences U.S.A. 118(49), 2021, e2109633118.
May J.C., Leaptrot K.L., Rose B.S., Wormwood Moser K.L., Deng L., Maxon L., DeBord D., McLean J.A., Resolving Power and Collision Cross Section Measurement Accuracy of a Prototype High-Resolution Ion Mobility Platform Incorporating Structures for Lossless Ion Manipulation, Journal of the American Society for Mass Spectrometry 2021, 32 (4), 1126-1137.
Leaptrot K.L., May J.C., Dodds J.N., McLean J.A. Ion mobility conformational lipid atlas for high confidence lipidomics, Nature Communications 2019, 10(1):985.
Picache J.A., Rose B.S., Balinski A., Leaptrot K.L., Sherrod S.D., May J.C., McLean J.A. Collision cross section compendium to annotate and predict multi-omic compound identities, Chemical Sciences 2018, 10(4):983-993.
May J.C., McLean J.A. Ion Mobility-Mass Spectrometry: Time-Dispersive Instrumentation, Analytical Chemistry 2015, 87: 1422-1436. |