Premium
Measurement of rare isotopologues of nitrous oxide by high‐resolution multi‐collector mass spectrometry
Author(s) -
Magyar Paul M.,
Orphan Victoria J.,
Eiler John M.
Publication year - 2016
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7671
Subject(s) - isotopologue , isotopomers , chemistry , isotope , nitrous oxide , mass spectrometry , isotope ratio mass spectrometry , analytical chemistry (journal) , isotopic ratio , isotope analysis , high resolution , isotopic signature , isotopes of nitrogen , environmental chemistry , nitrogen , molecule , chromatography , remote sensing , geology , physics , oceanography , organic chemistry , quantum mechanics
Rationale Bulk and position‐specific stable isotope characterization of nitrous oxide represents one of the most powerful tools for identifying its environmental sources and sinks. Constraining 14 N 15 N 18 O and 15 N 14 N 18 O will add two new dimensions to our ability to uniquely fingerprint N 2 O sources. Methods We describe a technique to measure six singly and doubly substituted isotopic variants of N 2 O, constraining the values of δ 15 N, δ 18 O, ∆ 17 O, 15 N site preference, and the clumped isotopomers 14 N 15 N 18 O and 15 N 14 N 18 O. The technique uses a Thermo MAT 253 Ultra, a high‐resolution multi‐collector gas source isotope ratio mass spectrometer. It requires 8–10 hours per sample and ~10 micromoles or more of pure N 2 O. Results We demonstrate the precision and accuracy of these measurements by analyzing N 2 O brought to equilibrium in its position‐specific and clumped isotopic composition by heating in the presence of a catalyst. Finally, an illustrative analysis of biogenic N 2 O from a denitrifying bacterium suggests that its clumped isotopic composition is controlled by kinetic isotope effects in N 2 O production. Conclusions We developed a method for measuring six isotopic variants of N 2 O and tested it with analyses of biogenic N 2 O. The added isotopic constraints provided by these measurements will enhance our ability to apportion N 2 O sources.