Dr. Kerim Gulyuz


 

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

 

Education:

State University of New York at Stony Brook, Ph.D. in Physics, December 2007

State University of New York at Stony Brook, M.A. in Physics, May 2002

Bogazici University, Istanbul, Turkey, B.S. in Physics, June 2000

 

Research:

My area of interest is in the field of instrument development for mass spectrometry of biomolecules, especially peptides, and obtain structural information by infrared spectroscopy. In my graduate research in the field of nuclear physics, I have worked on development of ion traps for investigation of shortly-lived radioactive isotopes, as well as the electronic and data analysis systems to complement that research. Now as a post doctoral researcher, I am applying those ideas in the field of mass spectrometry of peptides.

 

Infrared multiple-photon dissociation (IRMPD) spectroscopy is an emerging technique in structural characterization of ions in mass spectrometry. These experiments require a bright tunable laser source to allow absorption of tens to hundreds of photons. Free electron lasers (FELs) are ideally suited to this task, and the majority of such experiments on covalently bound molecular systems have been conducted at free electron laser (FEL) facilities, which are ideally suited to IRMPD spectroscopy in the mid-infrared region (500-2000 cm-1). In Polfer lab, I participate in development of a custom-built instrument that combines a mass spectrometer with a bench-top optical parameter oscillator (OPO) that covers the hydrogen stretching region (3000-4000 cm-1).

 

In a nutshell, our custom-built mass spectrometer consists of a commercial electrospray ionization (ESI) source (Analytica of Branford), a quadrupole mass filter (Ardara Technologies), and a quadrupole ion trap coupled to a time-of-flight drift tube (Jordan TOF products). ESI-generated ions are dissociated in-source by nozzle-skimmer dissociation and are mass selected by the quadrupole mass filter. Introduction of the ions into the QIT is mediated by a pulse of He buffer gas. The two idler beams from a continuous wave OPO laser (LINOS Photonics OS 4000) are focused through apertures in the ring electrode of the QIT, following a He gas pump down delay (~300 ms). Following laser irradiation, the remaining precursor and photofragments are then extracted into a time-of-flight spectrometer for mass analysis. A detailed description can be found in " Kerim Gulyuz, Corey N. Stedwell, Da Wang, and Nick C. Polfer, Hybrid quadrupole mass filter/quadrupole ion trap/time-of-flight-mass spectrometer for infrared multiple photon dissociation spectroscopy of mass-selected ions, Rev. Sci. Instrum, 2011, 82, 054101".

 

If you would like to read about my past research on Francium, please click on Francium Research.

 

 

Publications:

CURRENT RESEARCH

 

  • Stedwell, Galindo, Gulyuz, Roitberg, Polfer; "Crown-complexation of protonated amino acids: Influence on IRMPD spectra", J. Phys. Chem. A, 117 (6), 1181-1188 (2012)

     

  • Wang, Gulyuz, Stedwell, Yu, Polfer; "Effect of phenol and acidic side chains on the protonation sites of b2 ions confirmed by IRMPD spectroscopy", Int. J. of Mass Spectrom., 330-332, 144-151 (2012).
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  • Stedwell, Patrick, Gulyuz, Polfer; "Screening for phosphorylated and non-phosphorylated peptides by infrared photodissociation spectroscopy", Anal. Chem., 84 (22), 9907-9912 (2012).
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  • D Wang, K Gulyuz, CN Stedwell, NC Polfer; "Diagnostic NH and OH vibrations for oxazolone and diketopiperazine structures: b2 from protonated triglycine", J. Am. Soc. Mass Spectrom., 22, 1197-1203 (2011).
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  • K Gulyuz, CN Stedwell, D Wang, NC Polfer; "Hybrid quadrupole mass filter/quadrupole ion trap/time-of-flight mass spectrometer for infrared multiple photon dissociation spectroscopy of mass-selected ions", Rev. Sci. Instrum., 82, 054101 (2011).
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  • W Mino, K Gulyuz, D Wang, CN Stedwell, NC Polfer; "Gas-phase structure and dissociation chemistry of protonated tryptophan elucidated by infrared multiple-photon dissociation spectroscopy", J. Phys. Chem. Lett., 2, 299-304 (2011).
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    PAST RESEARCH

     

  • Sell, Gulyuz, Sprouse; "Collinear laser spectroscopy of francium using online rubidium vapor neutralization and amplitude modulated lasers" Rev. Sci. Instrum., 80, 123108 (2009).
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  • Tardiff, Behr, Chupp, Gulyuz, Lefferts, Lorenzon, Nuss-Warren, Pearson, Pietralla, Rainovski, Sell, Sprouse; "Polarization and relaxation rates of radon" Phys. Rev. C, 77, 052501 (2008).
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  • Tardiff, Chupp, Lorenzon, Nuss-Warren, Behr, Pearson, Gulyuz, Lefferts, Pietralla, Rainovski, Sell, Sprouse; "Polarization and relaxation of 209Rn" Nucl. Instrum. and Methods in Phys. Res. Sec. A, 579, Issue 1, 472-475 (2007).
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  • Aubin, Gomez, Gulyuz, Orozco, Sell, Sprouse; "Francium Developments at Stony Brook" Nucl. Phys. A, 746, 459-462 (2004).
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    Past Research:

    My past research interest was in the field of experimental nuclear physics in Dr. Gene Sprouse's group at Stony Brook University, with particular emphasis on cooling and trapping of Francium ions using a radiofrequency quadrupole (RFQ) trap to prepare trapped Fr for further measurements, such as alpha anisotropy and ultimately a g-factor measurement. Towards this goal, we have tested the experimental system with stable Rubidium ions and established a relationship between trap lifetime and number of ions in the trap, which was the primary topic of my Ph.D dissertation.

     

    The Francium project at Stony Brook began in 1990s with the objective of making measurements on weak interactions. Many experiments have been performed to measure the properties of excited levels of Fr by laser spectroscopy. A magneto-optical trap (MOT) has been developed to trap large number of atoms to make precision measurements. Fr is the heaviest alkali atom and the least stable of the first 103 elements with a half life of about 22 minutes, for longest lived isotope. Thus it is the least studied alkali atom. Francium’s electron-nucleon interaction is stronger than the one in any other lighter alkali atom and this property makes it a good candidate for weak interaction studies like anapole and dipole moments. Fr is also a good candidate for g-factor measurements. Nuclear g-factor has been previously with a precision of 2% for Cs, but a more precise measurement is necessary to test the atomic wavefunctions used for weak interaction measurement in Fr. We proposed a method to accomplish that.

     

    Since Fr is highly unstable, we produce it in a heavy ion nuclear fusion reaction, 100MeV O beam on Au target, at the Nuclear Structure Laboratory’s superconducting linear accelerator (LINAC). Radioactive nature of Fr requires it to be controlled remotely. After the production, Fr is sent to the experiment room where we have the MOT and our lasers set up. A figure of the entire transport system can be found at “Nuclear Physics A 746 (2004) 459c–462c ”. Several lifetime and hyperfine splitting measurements have been done on the atomic levels of Fr.

     

    Another type of measurement targeting the g-factor, which involves trapping of Fr ions in a linear radio-frequency quadrupole trap, has been proposed and developed. The idea is to trap Fr by electrostatic means using two linear RFQ traps. After its production, Fr is neutralized and polarized, and collinear laser spectroscopy is performed on Francium atoms. Fr is then landed on a hot surface to make it re-ionize while keeping its polarization state and it is then extracted and directed into the RFQ traps. Successful trapping is achieved using stable Rb and steps have been taken to trap Fr using the new apparatus. The next step would be to combine the neutralization, polarization and trapping parts to make alpha anisotropy measurements on Fr ions under a magnetic field. Below is a sketch of the apparatus.