Atmospheric Measurement Techniques Discussions www.atmos-meas-tech-discuss.net 1867-8610 2 6 2009 10.5194/amtd-2-3099-2009 http://www.atmos-meas-tech-discuss.net/2/3099/2009/ http://www.atmos-meas-tech-discuss.net/2/3099/2009/amtd-2-3099-2009.html http://www.atmos-meas-tech-discuss.net/2/3099/2009/amtd-2-3099-2009.pdf 3099 3126 2009-12-04 A liquid nitrogen-free preconcentration unit for measurements of ambient N₂O isotopomers by QCLAS J. Mohn C. Guggenheim B. Tuzson M. K. Vollmer L. Emmenegger Laboratory for Air Pollution & Environmental Technology, EMPA, Dübendorf, Switzerland Important information about the biogeochemical cycle of nitrous oxide (N₂O) can be obtained by measuring its three main isotopomers, ¹⁴N¹⁵N¹⁶O, ¹⁵N¹⁴N¹⁶O, and ¹⁴N¹⁴N¹⁶O, and the respective site-specific isotope ratios δ¹⁵N^α and δ¹⁵N^β. Absorption laser spectroscopy in the mid-infrared is a direct method for N₂O isotopomer analysis, yet not sensitive enough for atmospheric N₂O concentrations (320 ppb). To enable a fully-automated high precision N₂O isotopomer analysis at ambient concentrations, we built and optimized a liquid nitrogen-free preconcentration unit to be coupled to a quantum cascade laser (QCL) based spectrometer. Rigorous tests were conducted, using FTIR and quantum cascade laser absorption spectroscopy (QCLAS), to investigate recovery rates, conservation of isotopic signatures and spectral interferences after preconcentration. We achieve quantitative N₂O recovery of >99% with only minor, statistically not significant isotopic fractionation and no relevant spectral interferences from other atmospheric constituents. The developed preconcentration unit also has the potential to be applied to other trace gases and their isotopic composition. Bernard, S., Röckmann, T., Kaiser, J., Barnola, J.-M., Fischer, H., Blunier, T., and Chappellaz, J.: Constraints on N₂O budget changes since pre-industrial time from new firn air and ice core isotope measurements, Atmos. Chem. Phys., 6, 493–503, 2006. Bertolini, T., Rubino, M., Lubritto, C., D'Onofrio, A., Marzaioli, F., Passariello, I., and Terrasi, F.: Optimized sample preparation for isotopic analyses of CO₂ in air: Systematic study of precision and accuracy dependence on driving variables during CO₂ purification process, J. Mass Spectrom., 40, 1104–1108, doi:10.1002/jms.888, 2005. Billings, S. A.: Biogeochemistry: Nitrous oxide in flux, Nature, 456, 888–889, doi:10.1038/456888a, 2008. Brand, W. A.: PRECON: A fully automated interface for the pre-GC concentration of trace gases in air for isotopic analysis, Isot. Environ. Healt. S., 31, 277–284, doi:10.1080/10256019508036271, 1995. Brenninkmeijer, C. A. M. and Röckmann, T.: Mass spectrometry of the intramolecular nitrogen isotope distribution of environmental nitrous oxide using fragment-ion analysis, Rapid Commun. Mass Sp., 13, 2028–2033, doi:0951-4198/99/202028-06, 1999. Faist, J., Capasso, F., Sivco, D. L., Sirtori, C., Hutchinson, A. L., and Cho, A. Y.: Quantum Cascade Laser, Science, 264, 553–556, doi:10.1126/science.264.5158.553, 1994. FOEN and EMPA: Luftbelastung 2008, Messresultate des Nationalen Beobachtungsnetzes für Luftfremdstoffe (NABEL), Bern, 139~pp. , 2009. Gagliardi, G., Borri, S., Tamassia, F., Capasso, F., Gmachl, C., Sivco, D. L., Baillargeon, J. N., Hutchinson, A. L., and Cho, A. Y.: A frequency-modulated quantum-cascade laser for spectroscopy of CH₄ and N₂O isotopomers, Isot. Environ. Healt. S., 41, 313–321, doi:10.1080/10256010500384572, 2005. Ishijima, K., Sugawara, S., Kawamura, K., Hashida, G., Morimoto, S., Murayama, S., Aoki, S., and Nakazawa, T.: Temporal variations of the atmospheric nitrous oxide concentration and its $\delta^15$N and $\delta^18$O for the latter half of the 20th century reconstructed from firn air analyses, J. Geophys. Res., 112, D03305, doi:10.1029/2006JD007208, 2007. Miller, B. R., Weiss, R. F., Salameh, P. K., Tanhua, T., Greally, B. R., Mühle, J., and Simmonds, P. G.: Medusa: A sample preconcentration and GC/MS detector system for in situ measurements of atmospheric trace halocarbons, hydrocarbons, and sulfur compounds, Anal. Chem., 80, 1536–1545, doi:10.1021/ac702084k, 2008. Mohn, J., Forss, A. M., Brühlmann, S., Zeyer, K., Lüscher, R., Emmenegger, L., Novak, P., and Heeb, N.: Time-resolved ammonia measurement in vehicle exhaust, Int. J. Environ. Pollut., 22, 342–356, doi:10.1504/IJEP.2004.005548, 2004. Mohn, J., Werner, R. A., Buchmann, B., and Emmenegger, L.: High-precision $\delta^13$C-CO₂ analysis by FTIR spectroscopy using a novel calibration strategy, J. Mol. Struct., 834, 95–101, doi:10.1016/j.molstruc.2006.09.024, 2007. Mohn, J., Zeeman, M. J., Werner, R. A., Eugster, W., and Emmenegger, L.: Continuous field measurements of $\delta^13$C-CO₂ and trace gases by FTIR spectroscopy, Isot. Environ. Healt. S., 44, 241–251, doi:10.1080/10256010802309731, 2008. Nakayama, T., Fukuda, H., Kamikawa, T., Sugita, A., Kawasaki, M., Morino, I., and Inoue, G.: Measurements of the 3$\nu _3$ band of $^14$N$^15$N$^16$O and $^15$N$^14$N$^16$O using continuous-wave cavity ring-down spectroscopy, Appl. Phys. B, 88, 137–140, doi:10.1007/s00340-007-2653-3, 2007. Nelson, D. D., McManus, J. B., Herndon, S. C., Zahniser, M. S., Tuzson, B., and Emmenegger, L.: New method for isotopic ratio measurements of atmospheric carbon dioxide using a 4.3 μm pulsed quantum cascade laser, Appl. Phys. B, 90, 301–309, doi:10.1007/s00340-007-2894-1, 2008. Rahn, T. and Wahlen, M.: A reassessment of the global isotopic budget of atmospheric nitrous oxide, Global Biogeochem. Cy., 14, 537–543, 0886-6236/00/1999GB 900070, 2000. Ravishankara, A. R., Daniel, J. S., and Portmann, R. W.: Nitrous oxide (N₂O): The dominant ozone-depleting substance emitted in the 21st century, Science, 326, 123–125, doi:10.1126/science.1176985, 2009. Röckmann, T., Kaiser, J., and Brenninkmeijer, C. A. M.: The isotopic fingerprint of the pre-industrial and the anthropogenic N₂O source, Atmos. Chem. Phys., 3, 315–323, 2003. Röckmann, T. and Levin, I.: High-precision determination of the changing isotopic composition of atmospheric N₂O from 1990 to 2002, J. Geophys. Res., 110, D21304, doi:10.1029/2005JD006066, 2005. Rothman, L. S., Jacquemart, D., Barbe, A., Benner, D. C., Birk, M., Brown, L. R., Carleer, M. R., Chackerian, C., Chance, K., Coudert, L. H., Dana, V., Devi, V. M., Flaud, J. M., Gamache, R. R., Goldman, A., Hartmann, J. M., Jucks, K. W., Maki, A. G., Mandin, J. Y., Massie, S. T., Orphal, J., Perrin, A., Rinsland, C. P., Smith, M. A. H., Tennyson, J., Tolchenov, R. N., Toth, R. A., Vander Auwera, J., Varanasi, P., and Wagner, G.: The HITRAN 2004 molecular spectroscopic database, J. Quant. Spectrosc. Ra., 96, 139–204, doi:10.1016/j.jqsrt.2004.10.008, 2005. Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L.: IPCC, 2007: Climate Change 2007: The Physical Science Basis, Cambridge Univ. Press, Cambridge and New York, 987~pp., 2007. Toyoda, S. and Yoshida, N.: Determination of nitrogen isotopomers of nitrous oxide on a modified isotope ratio mass spectrometer, Anal. Chem., 71, 4711–4718, doi:10.1021/ac9904563, 1999. Toyoda, S., Yoshida, N., Urabe, T., Aoki, S., Nakazawa, T., Sugawara, S., and Honda, H.: Fractionation of N₂O isotopomers in the stratosphere, J. Geophys. Res., 106, 7515–7522, 2001. Toyoda, S., Iwai, H., Koba, K., and Yoshida, N.: Isotopomeric analysis of N₂O dissolved in a river in the Tokyo metropolitan area, Rapid Commun. Mass Sp., 23, 809–821, doi:10.1002/rcm.3945, 2009. Tuzson, B., Mohn, J., Zeeman, M. J., Werner, R. A., Eugster, W., Zahniser, M. S., Nelson, D. D., McManus, J. B., and Emmenegger, L.: High precision and continuous field measurements of $\delta^13$C and $\delta^18$O in carbon dioxide with a cryogen-free QCLAS, Appl. Phys. B, 92, 451–458, doi:10.1007/s00340-008-3085-4, 2008a. Tuzson, B., Zeeman, M. J., Zahniser, M. S., and Emmenegger, L.: Quantum cascade laser based spectrometer for in situ stable carbon dioxide isotope measurements, Infrared Phys. Techn., 51, 198–206, doi:10.1016/j.infrared.2007.05.006, 2008b. Uehara, K., Yamamoto, K., Kikugawa, T., and Yoshida, N.: Isotope analysis of environmental substances by a new laser-spectroscopic method utilizing different pathlengths, Sensor Actuat. B, 74, 173–178, doi:10.1016/S0925-4005(00)00729-2, 2001. Uehara, K., Yamamoto, K., Kikugawa, T., and Yoshida, N.: Site-selective nitrogen isotopic ratio measurement of nitrous oxide using 2 μm diode lasers, Spectrochim. Acta A, 59, 957–962, doi:10.1016/S1386-1425(02)00260-3, 2003. VDI: 2449 Part 1 – Prüfkriterien von Meßverfahren – Ermittlung von Verfahrenskenngrößen für die Messung gasförmiger Schadstoffe (Immission), Düsseldorf, 45~pp., 1995. Wächter, H. and Sigrist, M. W.: Mid-infrared laser spectroscopic determination of isotope ratios of N₂O at trace levels using wavelength modulation and balanced path length detection, Appl. Phys. B, 87, 539–546, doi:10.1007/s00340-007-2576-z, 2007. Wächter, H., Mohn, J., Tuzson, B., Emmenegger, L., and Sigrist, M. W.: Determination of N₂O isotopomers with quantum cascade laser based absorption spectroscopy, Opt. Express, 16, 9239–9244, doi:10.1364/OE.16.009239, 2008. Well, R., Flessa, H., Xing, L., Xiaotang, J., and Römheld, V.: Isotopologue ratios of N₂O emitted from microcosms with NH$_4^+$ fertilized arable soils under conditions favoring nitrification, Soil Biol. Biochem., 40, 2416–2426, doi:10.1016/j.soilbio.2008.06.003, 2008. Werle, P., Mucke, R., and Slemr, F.: The limits of signal averaging in atmospheric trace-gas monitoring by tunable diode-laser absorption-spectroscopy (TDLAS), Appl. Phys. B, 57, 131–139, doi:10.1007/BF00425997, 1993. Werner, R. A. and Brand, W. A.: Referencing strategies and techniques in stable isotope ratio analysis, Rapid Commun. Mass Sp., 15, 501–519, doi:10.1002/rcm.258, 2001. Werner, R. A., Rothe, M., and Brand, W. A.: Extraction of CO₂ from air samples for isotopic analysis and limits to ultra high precision $\delta^18$O determination in CO₂ gas, Rapid Commun. Mass Sp., 15, 2152–2167, doi: 10.1002/rcm.487, 2001. Yoshida, N. and Toyoda, S.: Constraining the atmospheric N₂O budget from intramolecular site preference in N₂O isotopomers, Nature, 405, 330–334, doi:10.1038/35012558, 2000.