| Autor: |
Wassenaar, Leonard I., Douence, Cedric, Fortson, Susan, Baer, Douglas S. |
| Předmět: |
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| Zdroj: |
Isotopes in Environmental & Health Studies; Jun2023, Vol. 59 Issue 3, p297-308, 12p |
| Abstrakt: |
The nitrogen and oxygen (δ15N, δ18O, δ17O) stable isotopic compositions of nitrate ( N O 3 – ) are crucial tracers of nutrient N sources and dynamics in aquatic and atmospheric systems. Methods to reduce aqueous N O 3 – to N2O gas (microbial or Cd method) before 15N and 18O isotope analyses require multi-step conversion or toxic chemicals, and 17O in N2O cannot be disentangled by IRMS due to isobaric interferences. This technical note describes the automation of the stable-isotope analyses of nitrate by coupling the new Ti method with a headspace autosampler and an N2O triple-isotope laser analyzer based on off-axis integrated cavity output spectroscopy. The automation yielded accurate and precise results for routine determinations of δ15N, δ18O, and δ17O values for aqueous nitrate in environmental waters. Systematic corrections were required for cavity pressure, N2O concentration and water vapour content to obtain the highest precision for all three isotopic ratios. For the first time, an automated laser-based system facilitates routine low-cost triple isotope analyses in studies where high-temporal resolution isotope analyses of NO3− are required but have been, until now, cost-prohibitive and time-consuming (e.g. atmospheric N pollution). [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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