Nitrogen isotope analysis of aqueous ammonium and nitrate by membrane inlet isotope ratio mass spectrometry (MIRMS) at natural abundance levels

Dyckmans, Jens; Eschenbach, Wolfram; Langel, Reinhard; Szwec, Lars; Well, Reinhard

doi:10.1002/rcm.9077

Cited by 10 publications

(6 citation statements)

References 23 publications

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Section: Resultsmentioning

confidence: 99%

“…In future studies, the current QMS detector might be replaced with an isotope-ratio mass spectrometer 50 or a laser spectrometer, 40 making isotopic analyses at lower concentration and natural abundance level possible. This has been confirmed for a conventional one-compound SPIN−MIRMS device by Dyckmans et al 50 and for a SPIN−laser spectroscopy system in our laboratory. Both studies analyzed 15 N/ 14 N in NO 3 − after reduction to N 2 O with Ti 3+ .…”

Section: Discussionmentioning

confidence: 99%

“…Although similar spiking-and-tracing experiments have been conducted before to gain constraints on N transformations and N 2 O production pathways in natural and engineered systems, 10 the analytical capacity to conduct online measurement provides more immediate evidence/constraints on N-cycling dynamics, which is particularly helpful in dynamic engineered systems, where reaction rates may change continuously with dynamic processes. In future studies, the current QMS detector might be replaced with an isotope-ratio mass spectrometer 50 or a laser spectrometer, 40 making isotopic analyses at lower concentration and natural abundance level possible. This has been confirmed for a conventional one-compound SPIN−MIRMS device by Dyckmans et al 50 and for a SPIN−laser spectroscopy system in our laboratory.…”

Section: Discussionmentioning

confidence: 99%

“…In principle, it is possible to correct for the interference by urea if concentrations are known or can at least be estimated. The mathematical formalism is provided by Well et al 53 This aspect was further investigated by Dyckmans et al 54 but is beyond the scope of this study. The 3N-SPIN-MIMS system was applied in two 4−5 h nitritation experiments (experiments 3 and 4 in Table 1) to monitor reactive nitrogen species and their 15 N abundances.…”

Section: Matrix Effects On 15 N Analyses In Reactive Nitrogen Species...mentioning

confidence: 99%

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Simultaneous ¹⁵N Online Analysis in NH₄⁺, NO₂^–, NO₃^–, and N₂O to Trace N₂O Production Pathways in Nitrogen-Polluted Aqueous Environments

Huang,

Eschenbach,

Wei

et al. 2023

ACS EST Water

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Engineered nitrogen (N) removal processes in water treatment plants and N-transformation reactions in polluted environments represent prominent sources of the potent greenhouse gas, nitrous oxide (N2O). The relevance of microbial and abiotic formation pathways can be assessed by using 15N tracer techniques. While 15N–N2O analysis with optical analyzers is straightforward, the quantification of atom % 15N of inorganic N compounds, such as ammonium (NH4 +), nitrite (NO2 –), and nitrate (NO3 –), requires discrete sample analyses that are time-consuming and labor-intensive. In this study, we developed an automated sample preparation unit, coupled to a membrane inlet quadrupole mass spectrometer, for the online, quasi-simultaneous analysis of atom % 15N in NH4 +, NO2 –, and NO3 –. This technique was designed and validated for 15N-spiking applications at moderate (100–200 μmol L–1, 1 atom % 15N) to high (2–3 mmol L–1, 33 atom % 15N) dissolved inorganic N concentrations typically encountered in sewer systems or contaminated watersheds. The high potential of the developed system, in combination with 15N–N2O analysis by Fourier-transform infrared spectroscopy, to constrain N transformations and sources of N2O was demonstrated in a feasibility study, where nitrifier denitrification was identified as the primary N2O formation pathway during the partial NH4 + oxidation to NO2 – in a lab-scale sequencing batch reactor.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Matrix Effects On 15 N Analyses In Reactive Nitrogen Species...mentioning

confidence: 99%

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Simultaneous ¹⁵N Online Analysis in NH₄⁺, NO₂^–, NO₃^–, and N₂O to Trace N₂O Production Pathways in Nitrogen-Polluted Aqueous Environments

Huang,

Eschenbach,

Wei

et al. 2023

ACS EST Water

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“…Measurements of δ 18 O values in water samples were done by TC/EA coupled to a Delta V plus IRMS (Thermo Finnigan, Bremen, Germany) via a ConFlo IV interface. The δ 15 N values of NH 4 + and NO 3 − were determined according to Dyckmans et al (2021) using a sample preparation unit for inorganic nitrogen (SPIN) coupled to a membrane inlet isotope ratio mass spectrometer (MIRMS; Delta plus; Thermo Finnigan) via a ConFlo III interface. Additional nutrient solution samples taken one day after the labeling were analyzed for their dissolved organic carbon content (DOC) using a liquiTOC analyzer (Elementar Analysensysteme GmbH, Langenselbold, Germany).…”

Section: Methodsmentioning

confidence: 99%

Sources of nitrous oxide emissions from hydroponic tomato cultivation: Evidence from stable isotope analyses

Karlowsky

Buchen‐Tschiskale²,

Odasso³

et al. 2023

Front. Microbiol.

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IntroductionHydroponic vegetable cultivation is characterized by high intensity and frequent nitrogen fertilizer application, which is related to greenhouse gas emissions, especially in the form of nitrous oxide (N2O). So far, there is little knowledge about the sources of N2O emissions from hydroponic systems, with the few studies indicating that denitrification could play a major role.MethodsHere, we use evidence from an experiment with tomato plants (Solanum lycopersicum) grown in a hydroponic greenhouse setup to further shed light into the process of N2O production based on the N2O isotopocule method and the 15N tracing approach. Gas samples from the headspace of rock wool substrate were collected prior to and after 15N labeling at two occasions using the closed chamber method and analyzed by gas chromatography and stable isotope ratio mass spectrometry.ResultsThe isotopocule analyses revealed that either heterotrophic bacterial denitrification (bD) or nitrifier denitrification (nD) was the major source of N2O emissions, when a typical nutrient solution with a low ammonium concentration (1–6 mg L−1) was applied. Furthermore, the isotopic shift in 15N site preference and in δ18O values indicated that approximately 80–90% of the N2O produced were already reduced to N2 by denitrifiers inside the rock wool substrate. Despite higher concentrations of ammonium present during the 15N labeling (30–60 mg L−1), results from the 15N tracing approach showed that N2O mainly originated from bD. Both, 15N label supplied in the form of ammonium and 15N label supplied in the form of nitrate, increased the 15N enrichment of N2O. This pointed to the contribution of other processes than bD. Nitrification activity was indicated by the conversion of small amounts of 15N-labeled ammonium into nitrate.Discussion/ConclusionComparing the results from N2O isotopocule analyses and the 15N tracing approach, likely a combination of bD, nD, and coupled nitrification and denitrification (cND) was responsible for the vast part of N2O emissions observed in this study. Overall, our findings help to better understand the processes underlying N2O and N2 emissions from hydroponic tomato cultivation, and thereby facilitate the development of targeted N2O mitigation measures.

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Nitrogen transformation as affected by decomposition of ¹⁵N‐labeled cover crop shoots and roots

Süß,

Kemmann,

Helfrich

et al. 2024

J. Plant Nutr. Soil Sci.

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BackgroundIncorporation of cover crop (cc) shoot and root biomass can have different effects on nitrogen (N) dynamics and the transformation of soil‐derived N and cc N.AimsThe objective was to determine the effects of different ccs, cc compartments (roots and shoots), and pretreatment of cc biomass (fresh vs. dried) on mineralization processes and on the transformation of soil and cc N following incorporation into a silty loam soil.MethodsSoil columns with incorporated 15N‐labeled root and shoot biomass of two cc species (winter rye and oil radish) and different pretreatments (dried and fresh) were incubated for 70 days at a constant temperature and soil moisture (8°C, 40% water‐filled pore space). Carbon and N transformation dynamics were determined repeatedly, distinguishing between N originating from cc biomass and from soil.ResultsNet CO2 emission was related to the amount of soluble cell components added with ccs. Net N mineralization was negatively related to the C:N ratio of cc biomass. The incorporation of dried cc biomass caused higher initial soil respiration and N immobilization than fresh biomass. All treatments with cc incorporation showed increased N2O emission. Emitted N2O‐N consisted mainly of cc N (55%–57%) in treatments with fresh shoot biomass, whereas soil N was the main source of N2O (75%) in the treatment with fresh oil radish roots. Recovery of cc 15N was affected by crop compartment and pretreatment. At the end of the incubation, it was 17.5%–42.3% in soil NO3−, 0.1%–8.1% in microbial biomass N, and less than 0.23% of cc N was found in cumulative N2O emission.ConclusionThe incorporation of cc roots and shoots had different effects on N mobilization and immobilization processes and on the partitioning of cc N. These processes can be influenced significantly by pretreatment of the added plant biomass (dried vs. fresh).

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Nitrogen isotope analysis of aqueous ammonium and nitrate by membrane inlet isotope ratio mass spectrometry (MIRMS) at natural abundance levels

Cited by 10 publications

References 23 publications

Simultaneous ¹⁵N Online Analysis in NH₄⁺, NO₂^–, NO₃^–, and N₂O to Trace N₂O Production Pathways in Nitrogen-Polluted Aqueous Environments

Simultaneous ¹⁵N Online Analysis in NH₄⁺, NO₂^–, NO₃^–, and N₂O to Trace N₂O Production Pathways in Nitrogen-Polluted Aqueous Environments

Sources of nitrous oxide emissions from hydroponic tomato cultivation: Evidence from stable isotope analyses

Nitrogen transformation as affected by decomposition of ¹⁵N‐labeled cover crop shoots and roots

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Nitrogen isotope analysis of aqueous ammonium and nitrate by membrane inlet isotope ratio mass spectrometry (MIRMS) at natural abundance levels

Cited by 10 publications

References 23 publications

Simultaneous 15N Online Analysis in NH4+, NO2–, NO3–, and N2O to Trace N2O Production Pathways in Nitrogen-Polluted Aqueous Environments

Simultaneous 15N Online Analysis in NH4+, NO2–, NO3–, and N2O to Trace N2O Production Pathways in Nitrogen-Polluted Aqueous Environments

Sources of nitrous oxide emissions from hydroponic tomato cultivation: Evidence from stable isotope analyses

Nitrogen transformation as affected by decomposition of 15N‐labeled cover crop shoots and roots

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Simultaneous ¹⁵N Online Analysis in NH₄⁺, NO₂^–, NO₃^–, and N₂O to Trace N₂O Production Pathways in Nitrogen-Polluted Aqueous Environments

Simultaneous ¹⁵N Online Analysis in NH₄⁺, NO₂^–, NO₃^–, and N₂O to Trace N₂O Production Pathways in Nitrogen-Polluted Aqueous Environments

Nitrogen transformation as affected by decomposition of ¹⁵N‐labeled cover crop shoots and roots