FTIR ANALYSIS OF THE FLOWING AFTERGLOW FROM A HIGH-FREQUENCY SPARK DISCHARGE ALLEN R. WHITE Department of Mechanical Engineering Rose-Hulman Institute of Technology Terre Haute, IN, USA KEVIN PFEUFFER, STEVE RAY, GARY M. HIEFTJE Department of Chemistry Indiana University Bloomington, IN, USA. 69 th Symposium on Molecular Spectroscopy June 16, 2014

* “Nitric Oxide Chemical Ionization Ion Trap Mass Spectrometry for the Determination of Automotive Exhaust Constituents” Mark A. Dearth, Keiji G. Asano, Kevin J. Hart, Michelle V. Buchanan, Douglas E. Goeringer, and Scott A. McLuckey, Anal. Chem. 1997, 69, NO + is an ionization source for alkanes, alkenes, and arenes via chemi ionization and is produced by the mechanisms * : Spark discharges in air produce ions, NO, and NO + : 69 th International Symposium on Molecular Spectroscopy June 16, 2014

69 th International Symposium on Molecular Spectroscopy June 16, 2014 (atypical) Spark Discharge Source:

100 mm 25mm Experimental Apparatus 69 th International Symposium on Molecular Spectroscopy June 16, 2014 Air: 2.3 l/min Discharge Frequency: Hz

Discharge Cell 69 th International Symposium on Molecular Spectroscopy June 16, 2014

Afterglow from Discharge Cell 2.6mm 69 th International Symposium on Molecular Spectroscopy June 16, 2014

TOFMS of Flowing Afterglow of Spark Discharge Cell 69 th International Symposium on Molecular Spectroscopy June 16, 2014 NO + N2+N2+ O2+O2+ Air: 2.3 l/min 800 Hz

Experimental Setup for Absorption FTIR of Afterglow Figure 8: Megatech Mk III Visible Engine Modified with Sapphire Combustion Chamber Bruker Vertex Hz 2.3 l/min air IR source: Parabolic Mirrors 69 th International Symposium on Molecular Spectroscopy June 16, 2014

Frequency (1/cm) Amplitude (arbitrary units) FTIR of Afterglow OH 69 th International Symposium on Molecular Spectroscopy June 16, Hz 2.3 l/min air 2 1/cm resolution

Amplitude (arbitrary units) Wavenumber (1/cm) Temp of afterglow from FTIR: ~800 K from match to HITRAN data 69 th International Symposium on Molecular Spectroscopy June 16, Hz 2.3 l/min air 2 1/cm resolution

EM interference is a barrier to Time Resolved FTIR, so analysis was pursued via other techniques. 69 th International Symposium on Molecular Spectroscopy June 16, 2014

Time of Flight Mass Spectrometry of High Frequency Spark Discharge 25mm 69 th International Symposium on Molecular Spectroscopy June 16, Hz 2.3 l/min air LECO Renaissance

NO + N2+N2+ O2+O2+ TOFMS of Flowing Afterglow of Spark Discharge Cell Air: 2.3 l/min 800 Hz 69 th International Symposium on Molecular Spectroscopy June 16, 2014

TOFMS Time History of Ion Production 69 th International Symposium on Molecular Spectroscopy June 16, 2014

Normalized Mass Spectra of N2 and NO in Discharge Afterglow 69 th International Symposium on Molecular Spectroscopy June 16, Hz 2.3 l/min air 1 Hz Samples

TOFMS Time Resolved Ion Production for each spark 69 th International Symposium on Molecular Spectroscopy June 16, 2014

Experimental Setup for UV/Vis Monochromator Figure 8: Megatech Mk III Visible Engine Modified with Sapphire Combustion Chamber Monochromator 800 Hz 2.3 l/min air nm 69 th International Symposium on Molecular Spectroscopy June 16, 2014

69 th International Symposium on Molecular Spectroscopy June 16, Hz 2.3 l/min air

NO ion production as a function of discharge frequency and power 69 th International Symposium on Molecular Spectroscopy June 16, 2014

Nitromethane 69 th International Symposium on Molecular Spectroscopy June 16, Hz 2.3 l/min air NIST Electron Impact Ionization Spectrum

Ethanol 69 th International Symposium on Molecular Spectroscopy June 16, Hz 2.3 l/min air NIST Electron Impact Ionization Spectrum

Conclusions Spark Discharges are potentially useful as a source for chemi ionization for ambient mass spectrometry Higher frequency and higher power discharges would increase the utility of the discharge Apparent electron impact ionization fragmentation of analyte requires further study 69 th International Symposium on Molecular Spectroscopy June 16, 2014

Research Support: Instrumentation Support:

Thank you to the Hieftje Lab! 69 th International Symposium on Molecular Spectroscopy June 16, 2014

Thank you. 69 th International Symposium on Molecular Spectroscopy June 16, 2014

NO is an ionization source for alkanes, alkenes, and arenes * :

Infrared Spectroscopy Interest for Automotive Purposes Advanced Combustion Laboratory 1942 Packard Ganske, Jane A. The Chemical Educator, Vol. 8 No.6 (2003)

FTIR ANALYSIS OF FLOWING AFTERGLOW FROM A HIGH-FREQUENCY SPARK DISCHARGE ALLEN WHITE, Department of Mechanical Engineering, Rose-Hulman Institute of Technology, Terre Haute, IN, USA; GARY M HIEFTJE, STEVE RAY, KEVIN PFEUFFER, Department of Chemistry, Indi- ana University, Bloomington, IN, USA. Plasmas are often used as ionization sources for ambient mass spectrometry (AMS). Here, the flowing afterglow of a novel high-energy spark discharge system, operated in nitrogen at high repetition rates, is investigated as a source for AMS. The spark discharge here is the same as that of an automobile ignition circuit.Combustion in automobile engines is initiated by a spark ignition system that is designed to deliver short-duration,high-voltage sparks to multiple engine cylinders. The arrangement utilized in this study is a modified discharge configuration designed to produce similarly short-duration, high- voltage discharges. It consists of an automotive ignition coil that is activated by a spark initiation circuit that discharges in turn into a cell with neutral gas input flow and ultimately into the collection orifice of a mass spectrometer. The discharge voltage is approximately 40kV at 800 Hz. High-frequency spark discharges in a nitrogen flow produce reagent ions such as NO+. In order to better evaluate the effectiveness of the discharge in producing reagent ions, an FTIR is utilized to measure IR active species such as nitric oxide, hydroxide, ozone, and water in the afterglow of the spark discharge during variation of discharge p