EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Applying the denitrification method to 15N and 18O analysis of nitrate in natural groundwater samples

Patricia Stock, Susanne Roder, and Diana Burghardt
Patricia Stock et al.
  • Technische Universität Dresden, Institute of Groundwater Management, Hydro Sciences, Germany (

This study aims to develop a simplified denitrification method for the δ15N and δ18O analysis of nitrate (NO3) in natural groundwater samples following Zhu et al. (Sci Total Environ. 2018; 633: 1370–1378) and Sigman et al. (Anal Chem. 2001; 73: 4145–4153). With the help of Pseudomonas aureofaciens bacteria, the simplified method induced denitrification of the sample and completely converted the NO3into measurable N2O while avoiding sample fractionation. In contrast to the classic denitrification method (Sigman et al., 2001), which is based on anaerobic cultivation, the bacteria are cultivated aerobically in the simplified method (Zhu et al., 2014). In this study, aerobic cultivation was performed in a nitrate-free medium. Unlike the other two methods, aerobic cultivation was performed without the addition or removal of nitrate in the liquid medium. This eliminates the need for another preparation step, saving time. There was no contamination with external NO3. After further optimising the influencing factors, the method yielded high accuracy and precision (standard deviations were generally ≤ 0.7‰ for δ18O and ≤ 0.3‰ for δ15N), confirming the suitability of this procedure. Finally, the potential applicability of the method was demonstrated by measuring the isotopic composition of NO3 in natural groundwater samples.

How to cite: Stock, P., Roder, S., and Burghardt, D.: Applying the denitrification method to 15N and 18O analysis of nitrate in natural groundwater samples, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4864,, 2020

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