Corey N. Stedwell


Office: CLB 302
Office Phone: 392-0536
E-mail: cstedwell@ufl.edu

 

Education:

University of Florida
Ph.D. in Physical Chemistry, 2009-2014
Graduate Research Project with Dr. Nick Polfer
Ion Spectroscopy/Mass Spectrometry

 

University of Montevallo
B.S. Chemistry; B.S. Mathematics, May 2009.  GPA 3.902/4.0
Undergraduate Research Interest: Synthesis and Characterization of Metalloporphyrins

 

Research:

We are interested in fundamental study of the gas-phase structure and dissociation chemistries of small biological molecules. Inherently, mass spectrometry (MS) provides little by way of structural information on a molecular system. On the other hand, infrared (IR) spectroscopy can reveal important structural details about gas-phase ions. The coupling of these two techniques into infrared multiple-photon dissociation (IRMPD) spectroscopy combines the ultra-low sensitivity of MS with the wealth of structural information from the IR measurements. However, many technical challenges (e.g., sufficient signal intensities, mixture separation, etc.) must be addressed prior to performing such measurements. My research focuses on the technique and instrument development necessary to perform such experiments on a custom-built quadrupole ion trap/time-of-flight mass spectrometer (QIT-ToF MS). We have constructed a custom electrospray ionization source consisting of an encapsulated spraying unit, a heated desolvation capillary, and an electrodynamic ion funnel. To ensure full compatibility with the existing instrument, each component was fully modeled using 3D CAD software (shown below). By careful control of driving and auxiliary gas flow rates, a large portion of the electrospray droplets can be effectively focused into the mass spectrometer for sampling. The newly designed ion source resulted in a signal-to-noise improvement of ~102–103, allowing for the study of biomolecules with lower ionization efficiencies/concentrations. Currently, the instrument is well suited to probe the dissociation chemistry (i.e., sequence scrambling that occurs during collision-induced dissociation) of small, gas-phase peptides via IRMPD spectroscopy.

 

 

Publications:

'Differentiating Sulfopeptide and Phosphopeptide Ions via Resonant Infrared Photodissociation', AL Patrick, CN Stedwell, NC Polfer; Anal. Chem., 2014, 86, 5547-5552.

 

Polfer, N.C.; Stedwell, C.N. Infrared Photodissociation of Biomolecular Ions. In Laser Photodissociation and Spectroscopy of Mass-separated Biomolecular Ions, 1st Edition; Polfer, N.C., Dugourd, P., Eds.; Lecture Notes in Chemistry 83; Springer International Publishing: Switzerland, 2013; pp 71-91.

 

Stedwell, C.N.; Polfer, N.C. Spectroscopy and the Electromagentic Spectrum. In Laser Photodissociation and Spectroscopy of Mass-separated Biomolecular Ions, 1st Edition; Polfer, N.C., Dugourd, P., Eds.; Lecture Notes in Chemistry 83; Springer International Publishing: Switzerland, 2013; pp 1-20.

 

'Structures of biomolecular ions in the gas phase probed by infrared light sources', CN Stedwell, JF Galindo, AE Roitberg, NC Polfer; Ann. Rev. Anal. Chem., 2013, 6.

 

'Crown-complexation of protonated amino acids: Influence on IRMPD spectra' CN Stedwell, JF Cruz, K Gulyuz, AE Roitberg, NC Polfer; J. Phys. Chem. A, 2013, 117, 1181-118.

 

'Screening for phosphorylated and non-phosphorylated peptides by infrared photodissociation spectroscopy', CN Stedwell, AL Patrick, K Gulyuz, NC Polfer; Anal. Chem., 2012, 84, 9907-9912.

 

'Effect of phenol and acidic side chains on the protonation sites of b2 ions confirmed by IRMPD spectroscopy', D Wang, K Gulyuz, CN Stedwell, L Yu, NC Polfer; Int. J. Mass Spectrom., 2012, 330, 144-151.

 

'Hybrid quadrupole mass filter/quadrupole ion trap/time-of-flight mass spectrometer for infrared multiple photon dissociation spectroscopy of mass-selected ions', K Gulyuz, CN Stedwell, D Wang, NC Polfer; Rev. Sci. Instrum., 2011, 82, 054101.

 

'Diagnostic NH and OH vibrations for oxazolone and diketopiperazine structures: b2 from protonated triglycine' D Wang, K Gulyuz, CN Stedwell, NC Polfer; J. Am. Soc. Mass Spectrom., 2011, 22, 1197-1203.

 

'Gas-phase structure and dissociation chemistry of protonated tryptophan elucidated by infrared multiple-photon dissociation spectroscopy' WK Mino Jr, K Gulyuz, D Wang, CN Stedwell, NC Polfer; J. Phys. Chem. Lett., 2011, 2, 299-304.