Steven J. Ray


Steven Ray.

Steven J. Ray


Steven J. Ray


Winkler Assistant Professor of Chemistry

Research Interests

Analytical Chemistry, Mass Spectrometry, and Chemical Instrumentation: Distance-of-Flight Mass Spectrometry, Soft-landing Mass Spectrometry, Novel Detector Platforms for Mass Spectrometry, New Mass Spectrometry Instrumentation and Ionization Sources, Atomic Spectrometry, Plasma Spectrochemistry


  • PhD, Indiana University, 2003
  • BS, Hope College, Holland, MI

Awards and Honors

  • Young Spectrochemist Award, Winter Conference on Plasma Spectrochemistry (2016).
  • Analytical and Bioanalytical Chemistry Best Paper Award (2014) “Zoom-TOFMS: addition of a constant-momentum-acceleration “zoom” mode to time-of-flight mass spectrometry.”, Anal. Bioanal. Chem., 406(29), 7419-30 (2014).
  • Lester Strock Medal, Society for Applied Spectroscopy (2014).
  • American Society for Mass Spectrometry Ron Hites Award for Best Manuscript (2013): “First distance-of-flight instrument: opening a new paradigm in mass spectrometry”, J. Am. Soc. Mass Spectrom., 22(1), 110-117, (2011).
  • R&D100 Award, “Array Detector Technology for Mass Spectrometry”, R&D Magazine (2011).


Novel Instrumentation and Methodologies for Analytical Chemistry.  Distance-of-Flight Mass Spectrometry and Time-of-Flight Mass Spectrometry Techniques and Instrumentation.  New Detector Technologies for Mass Spectrometry. Soft-landing Mass Spectrometry. Novel Plasma Novel Ionization Sources for Mass Spectrometry. Atomic Spectrometry Techniques.

Research Summary

Our laboratory focuses on the development of new instrumental and methodologies to advance analytical chemistry, predominantly in the area of mass spectrometry.  The development of A new measurement capability, or the marked improvement of an existing technique, can profoundly affect other areas of scientific exploration and generate new scientific discoveries.

Current Research areas are:

  • Distance-of-Flight Mass Spectrometry.
  • Solid-State Detector Arrays for Mass Spectrometry.
  • Soft-Landing Mass Spectrometry.
  • Atomic Spectrometry.
  • New Ionization Sources for Mass Spectrometry.
  • Novel Plasma Systems for Atomic Spectrometry.
  • Metallomics Analysis by Parallel Atomic and Molecular Mass Spectrometry.

Selected Recent Publications

  • Helium Conservation by Discontinuous Introduction in the Flowing Atmospheric-Pressure Afterglow Source for Ambient Desorption-Ionization Mass Spectrometry.”, Storey, A.P., Zeiri, O.M., Ray, S.J., and Hieftje, G.M., J. Anal. At. Spectrom., 30, 2017-2023, (2015).
  • Nanopipettes: Probes for Local Sample Analysis.”, Saha-Shah, A., Weber, A.E., Karty, J.A., Ray, S.J., Hieftje, G.M., and Baker, L.A., Chem. Sci., 6, 3334-3341, (2015).
  • Laser-Ablation Sampling for Inductively Coupled Plasma Distance-of-Flight Mass Spectrometry“, Gundlach-Graham, A.W., Dennis, E.A., Ray, S.J., Enke, C.G., Barinaga, C.J., Koppenaal, D.W., and Hieftje, G.M., J. Anal. At. Spectrom., 30, 139-147, (2014).
  • Detection of Counterfeit Electronic Components Through Ambient Mass Spectrometry and Chemometrics.” Pfeuffer, K. P., Caldwell, J., Shelley, J. T., Ray, S. J., and Hieftje, G. M., Analyst, 139(18), 4505-4511, (2014).
  • Zoom-TOFMS:  Addition of a Constant-Momentum-Acceleration “Zoom” Mode to Time-of-Flight Mass Spectrometry”, Dennis, E.A., Gundlach-Graham, A.W., Ray, S.J., Enke, C.G., Barinaga, C.J., Koppenaal, D.W., and Hieftje, G.M.,  Anal. Bioanal. Chem., 406(29), 7419-30, (2014).
  • Effect of internal and external conditions on ionization processes in the FAPA ambient desorption/ionization source”, Orejas, J., Pfeuffer, K.P, Ray, S.J., Pisonero, J., Sanz-Medel, A., Hieftje, G.M., Anal. Bioanal. Chem., 406, 7511-21, (2014).
  • Electrospray Ionization with Nanopipette Emitters with tip diameters of less than 100 nanometers”, Yuill, Elizabeth; Sa, Niya; Ray, Steven; Hieftje, Gary; Baker, Lane, Anal. Chem., 85(18), 8498-8502, (2013).
  • Interleaved Distance of Flight Mass Spectrometry: A Simple Method to Improve The Instrument Duty Factor”, Gundlach-Graham, A.W., Dennis, E.A., Ray, S.J., Enke, C.G., Barinaga, C.J., Koppenaal, D.W., and Hieftje, G.M., J. Am. Soc. for Mass Spectrom., 24, 1736-1744, (2013).
  • First Inductively Coupled Plasma–Distance-of-Flight Mass Spectrometer: Instrument Performance with a Microchannel Plate-Phosphor Image Detector”, Graham, A. W.; Dennis, E. A.; Ray, S. J.; Enke, C. G.; Carado, A. J.; Barinaga, C. J.; Koppenaal, D. W.; Hieftje, G. M., J. Anal. At. Spectrom., 28, 231-240, (2013).
  • Distance-of-Flight Mass Spectrometry: A New Paradigm for Mass Separation and Detection”, Christie G. Enke, Steven J. Ray, Alexander W. G. Graham,  Jeremy Felton, Charles J. Barinaga, David W. Koppenaal, and Gary M. Hieftje, Ann. Rev. Anal. Chem., 22(5), 487-504, (2012).