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An enhanced technique for automated determination of 15 N signatures of N 2 , (N 2 +N 2 O) and N 2 O in gas samples
Author(s) -
LewickaSzczebak Dominika,
Well Reinhard,
Giesemann Anette,
Rohe Lena,
Wolf Ulrike
Publication year - 2013
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.6605
Subject(s) - chemistry , nitrous oxide , denitrification , nitrogen , analytical chemistry (journal) , isotope , ammonium , isotopes of nitrogen , mass spectrometry , accuracy and precision , nitrification , environmental chemistry , chromatography , physics , organic chemistry , quantum mechanics , statistics , mathematics
RATIONALE An enhanced analytical approach for analyzing gaseous products from 15 N‐enriched pools has been developed. This technique can be used to quantify nitrous oxide (N 2 O) and dinitrogen (N 2 ) fluxes from denitrification. It can also help in distinguishing different N 2 ‐ and N 2 O‐forming processes, such as denitrification, nitrification, anaerobic ammonium oxidation or co‐denitrification. METHODS The measurement instrumentation was based on a commercially available automatic preparation system allowing collection and separation of gaseous samples. The sample transfer paths, valves, liquid nitrogen traps, gas chromatography column and open split of the original system were modified. A reduction oven (Cu) was added in order to eliminate oxygen and measure N 2 O‐N as N 2 . Gases leaving the separation system entered an isotope ratio mass spectrometer where masses 28 N 2 , 29 N 2 and 30 N 2 were measured. RESULTS The enhanced technique enabled rapid simultaneous measurement of stable isotope ratios 29 N 2 / 28 N 2 and 30 N 2 / 28 N 2 originating from dinitrogen alone (N 2 ) and from the sum of the denitrification products (N 2 +N 2 O) as well as the determination of 15 N enrichment in N 2 O. The 15 N fraction in the N pool undergoing N 2 and N 2 O production ( 15 X N ) and the contribution of N 2 and N 2 O originating from this pool ( d ) were determined with satisfactory accuracy of better than 3.3% and 2.9%, respectively. CONCLUSIONS The precision and accuracy of this method were comparable with or better than previously reported for similar measurements. The proposed method allows for the analysis of all quantities within one run, thus reducing the measurement and sample preparation time as well as increasing the reliability of the results. Copyright © 2013 John Wiley & Sons, Ltd.