Nitrogen (N₂) & Nitrous Oxide (N₂O) by GasBench-Precon-IRMS Sample Preparation

N₂ & N₂O gas samples must be supplied in septum capped vials preferably at atmospheric pressure (~100 kpa) but pressures up to 200 kpa are acceptable. Over-pressurized vials may burst during shipping. Vials should be evacuated prior to sample collection. Label each vial with a unique ID# as your data will reference your samples using this ID#.

Samples must be provided in 12 mL Exetainers with plastic screw-caps (Labco Ltd, High Wycombe, UK) or 20 mL headspace vials with rubber butyl septa crimp caps (see Supplies list). Other vial types are not acceptable.  Smaller Exetainer vials may be acceptable but must be approved prior to sample collection and shipment. Labco has a wide vial that ends in ###W/W.  The SIF DOES NOT accept the wide vials because they are too wide for our autosampler racks.   For ordering information, see the Supplies section below.

Sample vials should be free of particulate matter or slurries, as the particles will clog our autosampler needle. 

Sample vials or sample preparations not conforming to SIF requirements will not be analyzed.

Dissolved Gas Samples

If N₂ & N₂O gas samples are from the dissolved gases of waters, samples may be preserved using 10 µl of 50% w/v ZnCl₂ per milliliter of water sample.  Due to university regulations, we cannot accept samples preserved with mercuric chloride (HgCl₂). All samples originating from waters should be stored immersed in a secondary container that is filled with the source water (see Dalsgaard et al. 2000 for detailed procedures). 

We require at least 35-40 mm of headspace in 12 mL Exetainers or 20 mL Restek vials, to allow for needle penetration during analysis.

Enriched Gas Samples

If the analysis of enriched samples > 10 atom% is desired, or you do not know your range of isotopic enrichment, we require that you supply a small set of test samples or replicates that can be used to determine the appropriate instrumental configuration for your experimental samples.  

N₂O Isotopomer Samples

Samples with bulk N₂O concentrations >5 ppm should be submitted in 12-ml Labco Exetainer vials.

Samples with bulk N₂O concentrations <5 ppm must be submitted in 100-ml serum bottles (max OD, 52 mm).

Helpful Resources

Hamilton, S.K. and N.E. Ostrom 2007. Measurement of the stable isotope ratio of dissolved N₂ in ¹⁵N tracer experiments Limnol. Oceanogr.: Methods 5: 233–240.

Dalsgaard, T., et al., 2000. Protocol handbook for NICE—nitrogen cycling in estuaries: a project under the EU research programme: Marine Science and Technology (MAST III). National Environmental Research Institute, Silkeborg, Denmark

Laughlin, R.J. and R.J. Stevens. 2003.  Changes in composition of nitrogen-15-labeled gases during storage in septum-capped vials. Soil Sci. Soc. Am. J. 67:540–543.

LINX II (Lotic Intersite Nitrogen eXperiments) protocol: Lotix Intersite Nitrogen eXperiment/

Shipping
Carefully package groups of Exetainers in Ziplock bags, small boxes, or their original boxes with dividers. Then package these sets in larger, sturdy boxes with Styrofoam peanuts or bubble wrap. Make sure the samples are very secure; loose vials can shatter during shipping. Gas samples do not require refrigeration during shipping.

Please complete and submit the online Analysis Order Form and Sample List for your samples. Also, be sure to include a printed copy with your samples. The SIF uses this form to track your samples and to contact you regarding receipt of samples, data, and invoicing. For mixed analysis requests, we require the completion of a separate form for each type of analysis.

 

Supplies

*Note: Labco has a wider vial style that ends in ###W/W.  We DO NOT accept these vials at the SIF because the vials are too wide for our autosampler racks.