Mining the isotopic complexity of nitrous oxide: a review of challenges and opportunities

Preliminary assessment of stable nitrogen and oxygen isotopic composition of USGS51 and USGS52 nitrous oxide reference gases and perspectives on calibration needs

“…There is a need for common mass overlap corrections in mass spectrometric analysis and we encourage publication of spreadsheets to accomplish this task, as was recently done for the isotopic analysis of water by spectroscopic approaches . As mass overlap corrections for N 2 O are complicated and involve assumptions, such as equivalent isotopic fractionation during breakage of α and β nitrogen bonds during ionization, spectroscopic approaches may prove useful in evaluating the validity of such assumptions . There is a need for additional pure N 2 O gas isotope reference materials because, although USGS51 and USGS52 differ markedly in S P , they have similar bulk δ 15 N and δ 18 O values.…”

“…For a remarkably simple molecule, consisting of only two elements and three atoms, there is a surprising degree of isotopic complexity in nitrous oxide (N 2 O) . The two stable isotopes of nitrogen and three stable isotopes of oxygen combine to form 12 isotopic molecules or isotopocules.…”

Nitrous oxide production by ammonia oxidizers: Physiological diversity, niche differentiation and potential mitigation strategies

“…15 N-and 18 O-enriched substrates can distinguish N 2 O production from nitrification and denitrification processes in the environment (see Ostrom & Ostrom, 2017;Wrage-Mönnig et al, 2018), although their ability to distinguish autotrophic and heterotrophic processes has been questioned . 15 N-and 18 O-enriched substrates can distinguish N 2 O production from nitrification and denitrification processes in the environment (see Ostrom & Ostrom, 2017;Wrage-Mönnig et al, 2018), although their ability to distinguish autotrophic and heterotrophic processes has been questioned .…”

N and O isotope (δ15Nα, δ15Nβ, δ18O, δ17O) analyses of dissolved NO3− and NO2− by the Cd‐azide reduction method and N2O laser spectrometry

“…Because the Cd‐azide headspace samples contained only N 2 O gas and H 2 O vapor in an air atmosphere (N 2 , O 2 ) and no other spectral interfering gases, we disabled the default suite of instrumental trace gas (CO 2 , CO, CH 4 ) corrections that disentangle spectral line overlap, that would normally be required for atmospheric isotopic measurements of N 2 O in more complex gas atmospheres, such as soil, air or biogenic gas samples …”

“…Instead, we used the identical treatment (IT) approach whereby the δ 15 N or δ 18 O and δ 17 O values of N 2 O for calibration standards were derived from nitrate or nitrite salts that underwent sample preparation procedures identical to those of N 2 O as samples. The IT approach is especially critical for N 2 O laser spectrometry because both the sample and the calibration N 2 O carrier gas compositions need to be ensured “matrix equivalent” in order to avoid confounding effects of spectral broadening by unequal proportions of the key (N 2 , O 2 ) and interfering species like H 2 O, CO 2 , CO or CH 4 affecting the accurate determination of N 2 O isotopologue concentrations . For testing, we prepared nitrate isotopic reference materials (IAEA, Vienna, Austria; USGS, Reston, VA, USA) as well as laboratory standards from the co‐authors.…”