In:
Rapid Communications in Mass Spectrometry, Wiley, Vol. 30, No. 23 ( 2016-12-15), p. 2487-2496
Abstract:
In the last few years, the study of N 2 O site‐specific nitrogen isotope composition has been established as a powerful technique to disentangle N 2 O emission pathways. This trend has been accelerated by significant analytical progress in the field of isotope ratio mass spectrometry (IRMS) and more recently quantum cascade laser absorption spectroscopy (QCLAS). Methods The ammonium nitrate (NH 4 NO 3 ) decomposition technique provides a strategy to scale the 15 N site‐specific (SP ≡ δ 15 N α – δ 15 N β ) and bulk (δ 15 N bulk = (δ 15 N α + δ 15 N β )/2) isotopic composition of N 2 O against the international standard for the 15 N/ 14 N isotope ratio (AIR‐N 2 ). Within the current project 15 N fractionation effects during thermal decomposition of NH 4 NO 3 on the N 2 O site preference were studied using static and dynamic decomposition techniques. Results The validity of the NH 4 NO 3 decomposition technique to link NH 4 + and NO 3 − moiety‐specific δ 15 N analysis by IRMS to the site‐specific nitrogen isotopic composition of N 2 O was confirmed. However, the accuracy of this approach for the calibration of δ 15 N α and δ 15 N β values was found to be limited by non‐quantitative NH 4 NO 3 decomposition in combination with substantially different isotope enrichment factors for the conversion of the NO 3 − or NH 4 + nitrogen atom into the α or β position of the N 2 O molecule. Conclusions The study reveals that the completeness and reproducibility of the NH 4 NO 3 decomposition reaction currently confine the anchoring of N 2 O site‐specific isotopic composition to the international isotope ratio scale AIR‐N 2 . The authors suggest establishing a set of N 2 O isotope reference materials with appropriate site‐specific isotopic composition, as community standards, to improve inter‐laboratory compatibility. Copyright © 2016 John Wiley & Sons, Ltd.
Type of Medium:
Online Resource
ISSN:
0951-4198
,
1097-0231
Language:
English
Publisher:
Wiley
Publication Date:
2016
detail.hit.zdb_id:
2002158-6
detail.hit.zdb_id:
58731-X
SSG:
11
