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Faculty

Hao Chen
391 Clippinger Laboratories
740-593-0719
740-593-0148 (Fax)
chenh2@ohio.edu

Hao Chen Group

Associate Professor
Ph.D., Purdue University

Organic and Biological Mass Spectrometry

Information

Mass spectrometry is a fascinating analytical and biological technology. Our research focuses on the new mass-spec innovation based on newly discovered ion chemistry and novel instrumentation. The current projects are:

1. Liquid sample DESI —- the Study of Electrochemistry, Protein Conformation and Reaction Kinetics by Mass Spectrometry

We have extended the desorption electrospray ionization (DESI),1 an ambient ionization method, to the direct analysis of liquid samples. Due to its direct sampling and ionization properties, this Liquid Sample DESI-MS is versatile and has unique applications. For instance, it allows us to study electrochemistry, protein conformations, fast reaction kinetics, atmospheric pressure ion/molecule (or ion/ion) reactions, single droplet microextraction, etc.2-6

2. Selenium Chemistry for Biological Thiol Derivatization

Selenium reagents such as ebselen can be used to selectively and rapidly derivatize thiol peptides/proteins for mass spectrometric analysis.9 This reaction is highly selective, rapid, reversible and efficient. For instance, the Cysteine121 residue of β-lactoglubin A can be labeled using ebselen with quantitative conversion in 30 s

3. Protein footprinting using fast photolytic oxidation of protein (FPOP) method with various oxidants.

Chemical footprinting of proteins has long been proven to be an efficient method for probing protein-protein interactions. FPOP10 achieves protein oxidation on a microsecond timescale, making it a strong candidate for protein footprinting. The objective of this project is to develop new FPOP methods with novel laser-generated oxidative chemical probes such as the highly oxidative sulfate radial anion SO4-▪.

4. Atmospheric pressure ion chemistry

Tandem mass spectrometry is invaluable for chemical structure elucidation via examination of fragment ions after the activation and dissociation of gaseous precursor ions. Recently, an ambient ion thermal dissociation method11 has been established which allows the isolation and re-ionization of neutral fragments of peptide/protein ions at atmospheric pressure outside of the mass spectrometer. This method can also be used to seek green chemistry approaches in reaction methodology.12 For instance, ionic Borsche-Drechsel cyclization is feasible without the need for conventional acid catalysts.

Center for Intelligent Chemical Instrumentation (CICI)

References
  1. Takats, Z.; Wiseman, J. M.; Gologan, B.; Cooks, R. G. Science, 2004, 306, 471.
  2. Miao, Z.; Chen, H. J. Am. Soc. Mass Spectrom. 2009, 20, 10.
  3. Li, J.; Dewald, H. D.; Chen, H. Anal. Chem., 2009, 81, 9716.
  4. Zhang, Y.; Chen, H. Int. J. Mass Spectrom. 2010, 289, 98.
  5. Miao, Z.; Wu, S.; Chen, H. J. Am. Soc. Mass Spectrom. 2010, 21, 1730.
  6. Sun. X; Miao, Z.; Yuan, Z.; Harrington, P. B.; Colla, J.; Chen, H. Int. J. Mass Spectrom. 2010, 301, 102.
  7. Miao, Z.; Chen, H.; Liu, P.; Liu, Y. Anal. Chem. 2011, 83, 3994-3997.
  8. Ferguson, C. N.,;Benchaar, S. A.; Miao, Z.; Loo, J. A.; Chen, H. Anal. Chem. 2011, In press.
  9. Xu, K.; Zhang, Y.; Tang, B.; Laskin, J.; Roach, P. J.; Chen, H. Anal. Chem. 2010, 82, 6926.
  10. Gau, B.; Chen, H.; Zhang, Y.; Gross, M. L. Anal. Chem. 2010, 82, 7821.
  11. Hao Chen, Livia S. Eberlin, R. Graham Cooks, J. Am. Chem. Soc. 2007, 129, 5880.
  12. Chen, H.; Eberlin, L. S.; Nefliu, M.; Augusti, R.; Cooks, R. G., Angew. Chem. Int. Ed., 2008, 47, 3422.