1. On-line technique to determine the isotopic composition of total dissolved nitrogen.
- Author
-
Huygens D, Boeckx P, Vermeulen J, De Paepe X, Park A, Barker S, and Van Cleemput O
- Subjects
- Ecosystem, Nitrogen chemistry, Nitrogen Isotopes chemistry, Potassium Chloride chemistry, Reproducibility of Results, Solutions, Water chemistry, Nitrogen analysis, Online Systems instrumentation
- Abstract
A new on-line analytical setup for 15N measurements of total dissolved nitrogen (TDN) has been developed through the coupling of a high-temperature catalytic (Ce(IV)O2) oxidation furnace, a Cu reduction furnace, and an isotope ratio mass spectrometer. The detection limit for accurate delta15N measurements is 20 mg of N L-1. For N-containing compounds dissolved in water, a standard deviation on N concentration measurements of 0.2 mg of N L-1, independent of N concentration, has been found. Reproducibility on delta15N increased with increasing N concentration, with standard deviations varying from 0.8 to 0.1 per thousand in the range of 20-100 mg of N L-1. Salt matrixes, in which the N species might be dissolved, could influence the analysis capacity and continuity, mainly at concentrations above 0.1 M. To our knowledge, this system is the first successful on-line setup capable of performing routine delta15N and N concentration measurements of the TDN pool. Potential applications are large and are believed to result in an increased insight in N cycling and dissolved organic nitrogen behavior in terrestrial and aquatic ecosystems.
- Published
- 2007
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