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March 29, 2016 at 10:00 am

Chemistry Colloquium| Protein Analysis by Desorption Electrospray Ionization Mass Spectrometry, April 4

Picture1Ohio University’s Chemistry and Biochemistry Colloquium Series presents Dr. Andre Venter on “Protein Analysis by Desorption Electrospray Ionization Mass Spectrometry” on Monday, April 4, at 4:35 p.m. in Clippinger Laboratories 194.

Venter is Associate Professor of Chemistry at Western Michigan University.

Abstract:  Desorption Electrospray Ionization (DESI) is a method that allows the detection of organic molecules from ambient surfaces by mass spectrometry. Imaging of tissue samples by ambient mass spectrometry is an important new pathology tool and is used for tumor detection and identification, to study drug action and other important applications. Unfortunately, DESI-imaging is currently limited to the analysis of small molecules such as lipids, fatty acids, and small molecule therapeutics. Developing the ability to analyze proteins and determine their spatial distribution in tissues and cells would make imaging DESI-MS much more useful.

DESI is challenged by a molecular mass dependent loss in signal response. When proteins are analyzed by DESI-MS, the sensitivity decreases with increasing molecular weight, limiting the useful analytical range to proteins smaller than 25 kDa. By using Spray Desorption Collection and Reflective Electrospray Ionization – new tools we developed to decipher mechanistic aspects of the DESI technique – we demonstrated that this loss in sensitivity originates primarily from the incomplete dissolution of large biomolecules such as proteins into the desorption spray solvent during the millisecond timescale of the process. Learning the cause of the problem allowed us to propose improvements to the DESI experiment. Some preliminary results on our current efforts to improve on the detection of proteins by DESI-MS will be presented.

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