Metabolic Investigation of Volume-limited Specimens by Capillary Electrophoresis Electrospray Ionization Mass Spectrometry

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Poster Presentation
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Student Team Members: 
Christina Jeong Won Choi
Dr. Peter Nemes, Rosemary M. Onjiko
Other Team Members: 
Dr. Saswati Basu, Dr. Ziad Sahab, Camille Lombard
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I am a member of the varsity GW Women's Soccer team.
Project Abstract: 

Determining the metabolome, which encompasses all metabolites in a biological system, holds important implications in basic and applied life sciences, but this goal is largely dependent on the development of next-generation bioanalytical technologies. There is a high, yet unmet need to make measurements compatible with different volume regimes, especially with samples that are precious or rare such as patient biopsies or small populations of cells. In addition, detection should address the high chemical complexity and dynamic concentration range of metabolites (e.g., millimolar to picomolar) that are present in biological samples.

Here we present a custom-built analytical platform that combines volume-limited sampling and label-free identification of diverse types of metabolites. This advance relies on the combination of capillary electrophoresis (CE) and electrospray ionization mass spectrometry (ESI MS) for their respective advantages in separation and detection. In this presentation, we first demonstrate that our CE ESI MS platform is compatible with less than 10 nL sample volume, and then apply the platform to investigate the metabolome of single eggs of Killifish, an emerging model for gerontology. A systematic series of experiments showed that the detection limit of the platform was 18 fmol for amino acids, which was sufficiently low to measure naturally abundant metabolites in the egg. High-efficiency separation by CE and favorable limits of detection in combination with tandem MS helped the identification of a number of endogenous metabolites in the egg.

Our current efforts are aimed at improving the analytical figures of merits and to apply the technique to metabolomics investigations. We anticipate that this versatile platform will help illuminate metabolomic changes linked to development and aging as well as an array of other topics that have important implications to human health.