DOI: 10.1007/s11090-004-3133-8 Plasma Chemistry and Plasma Processing, Vol. 25, No. 4, August 2005 (© 2005) Laser-Induced Fluorescence (LIF) Probe for In-situ Nitric Oxide Concentration Measurement in a Non-thermal Pulsed Corona Discharge Plasma Reactor Xudong Hu, 1 Gui-Bing Zhao, 1 S. V. B. Janardhan Garikipati, 1 Kim Nicholas, 1 Stanislaw F. Legowski, 2 and Maciej Radosz 1,3 Received June 10, 2004; revised November 16, 2004 Laser-induced fluorescence (LIF) is an effective in-situ probe for NO concen- trations below 300ppm in a non-thermal plasma reactor. A new method has been developed to measure in-situ NO concentration in the reactor discharge region using a long-time—on the order of seconds—averaged fluorescence detec- tion. This method, for quantifying NO concentration in a nonthermal plasma reactor, is simpler than a short-time—on the order of nanoseconds—fluorescence detection. For accurate measurement based on the new method, the LIF inten- sity must be close to the corona-induced fluorescence (CIF) intensity; the CIF intensity serves as a guide in selecting the LIF intensity. We find that a kinetic model proposed earlier works for two-tube reactors and represents the NO con- centration in the middle of the reactor, which verifies the assumption of gas plug flow. KEY WORDS: LIF; NO; plasma; pulsed corona discharge reactor. 1. INTRODUCTION A low-temperature pulsed corona discharge plasma reactor can be effective in converting trace pollutants in flue gases into environmentally benign compounds. Corona discharge processes have been known for a long time and studied for the conversion of nitrogen oxides, sulfur diox- ides and volatile organic compounds. (1-3) The high voltage applied to the reactor electrodes breaks down molecules of the gas flowing through the 1 Department of Chemical & Petroleum Engineering, University of Wyoming, Laramie, WY 82071, USA. 2 Department of Electrical and Computer Engineering, University of Wyoming, Laramie, WY 82071, USA. 3 To whom correspondence should be addressed. Telephone: +1-307-766-2500; Fax: +1-307- 766-6777; e-mail: radosz@uwyo.edu 351 0272-4324/05/0800-0351/0 © 2005 Springer Science+Business Media, Inc.