Presentation on theme: "Simultaneous analysis of nitrogen and triple oxygen isotopes in low-amount atmospheric samples on filters – How low can we go? Chemical preparation combined."— Presentation transcript:
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 N 2 O – CF-IRMS Anna Smirnoff 1, Martine M. Savard 1, Robert Vet 2, Joelle Marion 1 and Marie-Christine Simard 1 1 Geological Survey of Canada, 490 rue de la Couronne, Quebec (Quebec), Canada G1K 9A9 2 Environment Canada, 4905 Dufferin Street, Toronto, Ontario, Canada M3H 5T4 ASITA-2013
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
Sample Preparation with Cd Reduction Prepare a reduction column based on EPA method 4500-NO 3 - Using EDTA (C 10 H 14 N 2 Na 2 O 8 ) as a chelate agent Pass sample through Cd-reduction column Reduce NO 2 - to N 2 O using NaN 3 (sodium azide) Analyze N 2 O using slightly modified Pre-Con 18.5 cm 25 cm 10 cm 5-cm ID 85 mL 2-mm ID 3.5-mm ID Cu-Cd granules Glass wool plug
Analytical Setup vent He vent Mg(ClO 4 ) 2 + NaOH water trapMg(ClO 4 ) 2 He LH 2 manual Valco6 port vent U LH 2 auto He RT-Q Bond Plot, 15m LH 2 auto Modified from Brand,1995 Gold Furnace MoleSieve GC Column To IRMS U U Pre-Con
Preparation for Cd-reduction Modified and tested for: 0.10 mg/L N-NO 3 Developed for: 0.28 mg/L N-NO 3 80 mL – 04/2013
Objectives Analyze new atmospheric samples with lower amount of material Assess if lower concentrations affect accuracy of 15 N, 17 O and 18 O determinations
Western Canada N-cycle Research Sampling Atmospheric sources of nitrogen-bearing compounds Characterized by 15 N, 17 O and 18 O TransportAgriculture Gas compressors and plants Coal-Fired Power Plants Upgraders OS Operations Desulphurization and hydrogen plants, boilers, heaters, turbines, vehicles, tailings ponds, etc.
15 N, 17 O and 18 O analyses Which method? Bacterial method: higher sample throughput smaller amount of material Chemical preparation – Gold Furnace: prompt return to analyzing sets of samples more reliable 15 N results from analyzing N 2 in atmospheric samples as compared to analyzing N 2 O with contribution mass-independent 17 O
Further Details Smirnoff, A., Savard, M. M., Vet, R., and Simard, M.C Nitrogen and triple oxygen isotopes in near-road air samples using chemical conversion and thermal decomposition. Rapid Communications in Mass spectrometry, v. 26, 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.