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ASITA-2013

ASITA-2013.

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ASITA-2013

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  1. ASITA-2013 Simultaneous analysis of nitrogen and triple oxygen isotopes in low-amount atmospheric samples on filters – How low can we go?Chemical preparation combined with gold-furnace breaking of N2O – CF-IRMSAnna Smirnoff1, Martine M. Savard1, Robert Vet2, Joelle Marion1 and Marie-Christine Simard11Geological Survey of Canada, 490 rue de la Couronne, Quebec (Quebec), Canada G1K 9A92Environment Canada, 4905 Dufferin Street, Toronto, Ontario, Canada M3H 5T4

  2. Outline • Remind what we have been doing previously • Explain new challenges • Describe how we are trying to overcome them • Discuss pros and cons of our approach

  3. 5-cm ID 85 mL 10 cm 2-mm ID 25 cm 3.5-mm ID 18.5 cm Cu-Cd granules Glass wool plug Sample Preparation with Cd Reduction • Prepare a reduction column based on EPA method 4500-NO3- • Using EDTA (C10H14N2Na2O8) as a chelate agent • Pass sample through Cd-reduction column • Reduce NO2- to N2O using NaN3 (sodium azide) • Analyze N2O using slightly modified Pre-Con

  4. Valco 6 port vent vent vent Analytical Setup To IRMS He water trapMg(ClO4 )2 MoleSieve GC Column Mg(ClO4 )2 + NaOH He RT-Q Bond Plot, 15m Gold Furnace auto auto He manual U U U Modified from Brand,1995 LH2 LH2 LH2 Pre-Con

  5. 2009-2010 2010 – 04/2013 80mL 80mL Developed for: 0.28 mg/L N-NO3 Modified and tested for: 0.10 mg/L N-NO3 Preparation for Cd-reduction

  6. Objectives Analyze • new atmospheric samples with lower amount of material Assess • if lower concentrations affect accuracy of 15N, 17O and 18O determinations

  7. Western Canada N-cycle Research Sampling Transport Coal-Fired Power Plants Upgraders Gas compressors and plants Agriculture Atmospheric sources of nitrogen-bearing compounds • Characterized by 15N, 17O and 18O Desulphurization and hydrogen plants, boilers, heaters, turbines, vehicles, tailings ponds, etc. OS Operations

  8. 1- Teflon filter • 2- Nylon filter • 3- Citrated cellulose filter • 4- Maxxam cartridges Wet-only samplers - precipitation Filterpacks - dry material

  9. Sample details

  10. 80mL 50mL Reason • Filters from individual pumps were not combined Samples - Before and Now Before Now 0.10 mg/L N-NO3 0.05 mg/L N-NO3

  11. Standards - As before

  12. d15NResults Calibration Curves 200 NOW y = 2.05x - 1.1 150 100 50 y = 2.04x - 0.5 0 Before -50 -10 0 10 20 30 40 50 60 70 80 90 100

  13. 60 70 60 50 50 Now 40 Now 40 y = 1.62x + 4.6 30 30 y = 1.62x + 20.4 y = 1.45x + 1.2 y = 1.47x + 16.2 20 20 Before 10 Before 10 0 -10 0 -20 -10 -30 -20 -40 -30 -20 -10 0 10 20 30 -30 -20 -10 0 10 20 30 40 50 d17O and d18O ResultsCalibration curves d17O d18O

  14. Why slope is different? Possible reason… • Replacement of Imidazole with EDTA?

  15. Imidazole Ethylenediaminetetraacetic acid (EDTA) O H HO O C N OH N C C N H H N HO O OH H O Replaced: • Imidazole with EDTA: Protocol modifications

  16. Validating results using standards

  17. Bacterial method: • higher sample throughput • smaller amount of material Chemical preparation – Gold Furnace: • prompt return to analyzing sets of samples • more reliable d15N results from analyzing N2 in atmospheric samples as compared to analyzing N2O with contributionmass-independent 17O 15N, 17O and 18O analysesWhich method?

  18. Further Details • Smirnoff, A., Savard, M. M., Vet, R., and Simard, M.C. 2012. Nitrogen and triple oxygen isotopes in near-road air samples using chemical conversion and thermal decomposition. Rapid Communications in Mass spectrometry,v. 26, 2791-2804. • This research is a part of the CORES project of the Geological Survey of Canada conducted within the Environmental Geoscience Program of Natural Resources Canada. The research is conducted in close collaboration with Environment Canada.

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