In recent years, research and applications of the N₂O site-specific nitrogen isotope composition have advanced, reflecting awareness of the contribution of N₂O to the anthropogenic greenhouse effect, and leading to significant progress in instrument development. Further dissemination of N₂O isotopomer analysis, however, is hampered by a lack of internationally agreed gaseous N₂O reference materials and an uncertain compatibility of different laboratories and analytical techniques.

In a first comparison approach, eleven laboratories were each provided with N₂O at tropospheric mole fractions (target gas T) and two reference gases (REF1 and REF2). The laboratories analysed all gases, applying their specific analytical routines. Compatibility of laboratories was assessed based on N₂O isotopocule data for T, REF1 and REF2. Results for T were then standardised using REF1 and REF2 to evaluate the potential of N₂O reference materials for improving compatibility between laboratories.

Compatibility between laboratories depended on the analytical technique: isotope ratio mass spectrometry (IRMS) results showed better compatibility for δ¹⁵N values, while the performance of laser spectroscopy was superior with respect to N₂O site preference. This comparison, however, is restricted by the small number of participating laboratories applying laser spectroscopy. Offset and two-point calibration correction of the N₂O isotopomer data significantly improved the consistency of position-dependent nitrogen isotope data while the effect on δ¹⁵N values was only minor.

The study reveals that for future research on N₂O isotopocules, standardisation against N₂O reference material is essential to improve interlaboratory compatibility. For atmospheric monitoring activities, we suggest N₂O in whole air as a unifying scale anchor. Copyright © 2014 John Wiley & Sons, Ltd.