Steve Kregel

Steve Kregel

Assistant Professor

    Olin Hall 207
    (309) 677-4866



Dr. Kregel earned his B.S. in Chemistry from The University of Illinois at Urbana-Champaign in 2013. While there he performed undergraduate research with Professor Ben McCall focusing on developing a new type of laser system for high resolution molecular spectroscopy of astrochemically relevant species. He then earned his Ph.D. in Analytical Chemistry from the University of Wisconsin-Madison in 2018 while working with Professor Etienne Garand. Dr. Kregel’s thesis work was focused on construction an instrument capable of acquiring photoelectron spectra of molecular anions, and investigating the electronic structure of polyaromatic hydrocarbons. After graduation he spent nine months at the National Center for Quantitative Biology for Complex Systems, followed by 15 months at PPD, a pharmaceutical analysis company. In 2020 he returned to the University of Wisconsin-Madison to conduct post-doctoral research with Professors Tim Bertram and Gil Nathanson as part of the NSF Center for Aerosol Impacts on Chemistry of the Environment. While a post-doctoral researcher Dr. Kregel investigated the temperature dependence of atmospheric reactions and developed a low-cost circuit for powering components within mass spectrometers. This circuit serves as the basis for his current scholarship work at Bradley University in collaboration with Professor Tim Bertram at The University of Wisconsin-Madison.


Dr. Kregel’s primary teaching responsibilities include: 

  • General Chemistry I (CHM 110)
  • Analytical Chemistry and Lab (CHM 326)
  • Instrumental Analysis and Lab (CHM 420/520)


Broadly, the Kregel group is focused on the development and implementation of low-cost open-source hardware for mass spectrometry. Key application areas include lowering the cost of making mass-resolved measurements of atmospheric volatile organic compounds and educating future generations of instrument developers (The Arnold and Mabel Beckman Foundation), and the integration of optical spectroscopy with mass spectrometry. (Bradley University Start-up Funding). This integration will enable fundamental studies of ion behavior, as well as provide a method for the rapid identification of environmental pollutants currently necessitating chromatographic separation. Notable advances in these areas include the development of the Wisconsin Oscillator, a low-cost, open-source circuit capable of powering many non-mass-selective components within mass spectrometers. Current efforts to improve the Wisconsin Oscillator are focused on enabling it to control mass selective ion traps and quadrupoles, which will drastically lower the cost of custom mass spectrometers. For more information regarding work in the Kregel group, see our website at:


Kregel, S.J.; Derrah, T.; Moon, S.; Limmer, D.; Nathanson, G.N.; Bertram, T.H.; Weak Temperature Dependance of the Relative Rates of Chlorination and Hydrolysis of N2O5 in NaCl-Water Solutions. The Journal of Physical Chemistry A, 2023, 127, 7, 1675-1685.

Kregel, S.J.*; Thompson, B.J.; Nathanson, G.N.; Bertram, T.H.; The Wisconsin Oscillator: A Low-Cost Circuit for Powering Ion Guides, Funnels and Traps.  Journal of the American Society for Mass Spectrometry, 32, 12, 2821-2826 (2021).

Kregel, S.J.; Garand, E., Ground and low-lying excited states of phenoxy, 1-naphthoxy, and 2-naphthoxy radicals via anion photoelectron spectroscopy. The Journal of Chemical Physics 149 (7) 074309 (2018).

Kregel, S.J.; Thurston, G.K.; Garand, E. Photoelectron spectroscopy of anthracene and fluoranthene radical anions. The Journal of Chemical Physics. 148 (23) 2343060 (2018). (Editor’s Pick).

Voss, J.M.; Kregel, S.J.; Fischer, K.C.; & Garand, E. IR-IR Conformation Specific Spectroscopy of Na+(Glucose) Adducts. Journal of The American Society for Mass Spectrometry, 29, 42-50 (2018).

Kregel, S.J.; Thurston, G.K.; Zhou, J.; & Garand, E. A multi-plate velocity-map imaging design for high-resolution photoelectron spectroscopy. The Journal of Chemical Physics. 147 094201 (2017).