JEP  Vol.7 No.12 , November 2016
Detecting Nitrous Oxide in Complex Mixtures Using FTIR Spectroscopy: Silage Gas
Nitrous oxide (N2O) is a greenhouse gas with about 300 times the global warming potential (GWP) of carbon dioxide (CO2). It is emitted from a wide range of sources and is responsible for about 6% of anthropogenic US greenhouse gas emissions. Analytical techniques are needed that can measure concentrations of N2O rapidly and inexpensively in sources that are also emitting other compounds that may interfere with the analytical process. In this work, we demonstrate the use of Fourier Transform Infrared (FTIR) spectroscopy to analyze N2O in the complex mixture of gases produced during the early phase of the silage making process. Silage gas samples were collected into Tedlar bags from the bucket silos during the first week of corn ensiling. A bag of the silage gas was analyzed using a Bruker FTIR spectrometer coupled with a long optical path length White Cell. First, N2O infrared absorption bands were identified in the FTIR spectra of the silage gas by comparing them to both standard N2O gas and simulated infrared spectra which confirmed that N2O was present in the silage gas. Then, N2O concentration in the silage gas was derived from the FTIR spectra using LINEFIT program. It was demonstrated that FTIR spectroscopy is a viable method for measuring N2O concentrations in the silage gas.
Cite this paper: Zhao, Y. , Wexler, A. , Hase, F. , Pan, Y. and Mitloehner, F. (2016) Detecting Nitrous Oxide in Complex Mixtures Using FTIR Spectroscopy: Silage Gas. Journal of Environmental Protection, 7, 1719-1729. doi: 10.4236/jep.2016.712139.

[1]   Myhre, G., et al. (2013) Anthropogenic and Natural Radiative Forcing. In: Stocker, T.F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V. and Midgley, P.M. Eds., Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK and New York, USA, p. 659.

[2]   California Air Resources Board (CARB) (2006) California Global Warming Solutions Act of 2006 (AB32).

[3]   Reid, W.S., Turnbull, J.E., Sabourin, H.M. and Ihnat, M. (1984) Silo Gas: Production and detection. Canadian Agricultural Engineering, 25, 197-207.

[4]   Hafner, S.D., Howard, C., Muck, R.E., Franco, R.B., Montes, F., Green, P.G., Mitloehner, F, Trabue, S.L. and Rotz, C.A. (2013) Emission of Volatile Organic Compounds from Silage: Compounds, Sources, and Implications. Atmospheric Environment, 77, 827-839.

[5]   Hafner, S.D., Franco, R.B., Kung Jr., L., Rotz, C.A. and Mitloehner, F. (2014) Potassium Sorbate Reduces Production of Ethanol and 2 Esters in Corn Silage. Journal of Dairy Sciences, 97, 7870-7878.

[6]   Linn, D.M. and Doran, J.W. (1984) Effect of Water-Filled Pore Space on Carbon Dioxide and Nitrous Oxide Production in Tilled and Nontilled Soils. Soil Science Society of America Journal, 48, 1267-1272.

[7]   Van Groenigen, J.W., Kasper, G.J., Velthof, G.L., van den Pol-van Dasselaar, A. and Kuikman, P.J. (2004) Nitrous Oxide Emissions from Silage Maize Fields under Different Mineral Nitrogen Fertilizer and Slurry Applications. Plant and Soil, 263, 101-111.

[8]   Liu, C., Yao, Z., Wang, K. and Zheng, X. (2014) Three-Year Measurements of Nitrous Oxide Emissions from Cotton and Wheat-Maize Rotational Cropping Systems. Atmospheric Environment, 96, 201-208.

[9]   Wang, L.C. and Burries, R.H. (1960) Mass Spectrometric Study of Nitrogenous Gases Produced by Silage. Agricultural and Food Chemistry, 8, 239-242.

[10]   Zhao, Y., Strong, K., Kondo, Y., Koike, M., Matsumi, Y., Irie, H., Rinsland, C.P., Jones, N. B., Suzuki, K., Nakajima, H., Nakane, H. and Murata, I. (2002) Spectroscopic Measurements of Tropospheric CO, C2H6, C2H2, and HCN in Northern Japan. Journal of Geophysical Research: Atmospheres, 107, ACH 2-1-ACH 2-16.

[11]   Wunch, D., Taylor, J.R., Bernath, D. Fu, P., Drummond, J.R., Midwinter, C., Strong, K. and Walker, K.A. (2007) Simultaneous Ground-Based Observations of O3, HCl, N2O, and CH4 over Toronto, Canada by Three Fourier Transform Spectrometers with Different Resolutions. Atmospheric Chemistry and Physics, 7, 1275-1292.

[12]   Hase, F., Blumenstock, T. and Paton-Walsh, C. (1999) Analysis of the Instrumental Line Shape of High-Resolution Fourier Transform IR Spectrometers with Gas Cell Measurements and New Retrieval Software. Applied Optics, 38, 3417-3422.

[13]   Hase, F. (2012) Improved Instrumental Line Shape Monitoring for the Ground-Based, High-Resolution FTIR Spectrometers of the Network for the Detection of Atmospheric Composition Change. Atmospheric Measurement Techniques, 5, 603-610.

[14]   Hase, F., Drouin, B.J., Roehl, C.M., Toon, G.C., Wennberg, P.O., Wunch, D., Blumenstock, T., Desmet, F., Feist, D.G., Heikkinen, P., De Mazière, M., Rettinger, M., Robinson, J., Schneider, M., Sherlock, V., Sussmann, R., Té, Y., Warneke, T. and Weinzierl, C. (2013) Calibration of Sealed HCl Cells Used for TCCON Instrumental Line Shape Monitoring. Atmospheric Measurement Techniques, 6, 3527-3537.

[15]   Frey, M., Hase, F., Blumenstock, T., GroB, J., Kiel, M., Mengistu Tsidu, G., Schafer, K., Sha, M.K. and Orphal, J. (2015) Calibration and Instrumental Line Shape Characterization of a Set of Portable FTIR Spectrometers for Detecting Greenhouse Gas Emissions. Atmospheric Measurement Techniques, 8, 3047-3057.

[16]   Neal, W.M. and Becker, R.B. (1933) A Type of Laboratory Silo and Its Use with Crotalaria. Journal of Agricultural Research, 47, 617-625.

[17]   Johnson, H.E., Merry, R.J., Davies, D.R., Kell, D.B., Theodorou, M.K. and Griffith, G.W. (2005) Vacuum Packing: A Model System for Laboratory-Scale Silage Fermentations. Journal of Applied Microbiology, 98, 106-113.

[18]   Rothman, L.S., et al. (2009) The HITRAN 2008 Molecular Spectroscopic Database. Journal of Quantitative Spectroscopy &. Radiative Transfer, 110, 533-572.

[19]   Plyler, E.K., Tidwell, E.D. and Maki, A.G. (1964) Infrared Absorption Spectrum of Nitrous Oxide (N2O) From 1830 cm-l to 2270 cm-l. Journal of Research of the National Bureau of Standards-A. Physics and Chemistry, 68A, 79-86.

[20]   Plyler, E.K. and Barker, E.F. (1931) The Infrared Spectrum and the Molecular Configuration of N2O. Physical Review, 38, 1827-1836.

[21]   Martin, P.E. and Barker, E.F. (1932) The Infrared Absorption Spectrum of Carbon Dioxide. Physical Review, 41, 219-303.

[22]   Smith, T.E.L., Wooster, M.J., Tattaris, M. and Griffith, D.W.T. (2011) Absolute Accuracy and Sensitivity Analysis of OP-FTIR Retrievals of CO2, CH4 and CO over Concentrations Representative of “Clean Air” and “Polluted Plumes”. Atmospheric Measurement Techniques, 4, 97-116.