Thünen Institute of Climate-Smart Agriculture, Braunschweig, Germany.
Rapid Commun Mass Spectrom. 2013 Jul 15;27(13):1548-58. doi: 10.1002/rcm.6605.
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 (N2O) and dinitrogen (N2) fluxes from denitrification. It can also help in distinguishing different N2- and N2O-forming processes, such as denitrification, nitrification, anaerobic ammonium oxidation or co-denitrification.
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 N2O-N as N2. Gases leaving the separation system entered an isotope ratio mass spectrometer where masses (28)N2, (29)N2 and (30)N2 were measured.
The enhanced technique enabled rapid simultaneous measurement of stable isotope ratios (29)N2/(28)N2 and (30)N2/(28)N2 originating from dinitrogen alone (N2) and from the sum of the denitrification products (N2 +N2O) as well as the determination of (15)N enrichment in N2O. The (15)N fraction in the N pool undergoing N2 and N2O production ((15)X(N)) and the contribution of N2 and N2O originating from this pool (d) were determined with satisfactory accuracy of better than 3.3% and 2.9%, respectively.
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.
已经开发出一种用于分析（15）N 富化池产生的气态产物的增强分析方法。该技术可用于量化反硝化作用产生的氧化亚氮（N2O）和氮气（N2）通量。它还有助于区分不同的 N2 和 N2O 形成过程，如反硝化、硝化、厌氧氨氧化或共反硝化。
测量仪器基于商业上可用的自动制备系统，允许收集和分离气态样品。修改了样品传输路径、阀门、液氮阱、气相色谱柱和原始系统的开放分裂。添加了还原炉（Cu）以消除氧气并测量 N2O-N 为 N2。离开分离系统的气体进入同位素比质谱仪，在那里测量质量 (28)N2、(29)N2 和 (30)N2。
增强的技术能够快速同时测量来自单独氮气（N2）和反硝化产物（N2+N2O）的稳定同位素比（29）N2/(28)N2 和 (30)N2/(28)N2，以及氧化亚氮中的（15）N 富集。正在产生 N2 和 N2O 的 N 池中的（15）N 分数（(15)X(N)）和来自该池的 N2 和 N2O 的贡献（d）的测定具有令人满意的精度，优于 3.3%和 2.9%。
该方法的精度和准确性与类似测量的先前报道相当或更好。该方法允许在一次运行中分析所有数量，从而减少测量和样品制备时间，并提高结果的可靠性。
