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There’s another recent update with tips and tricks for the method that may be useful to folks:

Weigand, M. A., Foriel, J., Barnett, B., Oleynik, S. & Sigman, D. Updates to instrumentation and protocols for isotopic analysis of nitrate by the denitrifier method. Rapid Commun. Mass Spectrom. 30, 1365–1383 (2016). https://onlinelibrary.wiley.com/doi/abs/10.1002/rcm.7570


On Mon, Sep 3, 2018 at 10:47 AM, Andrew Schauer <[log in to unmask]> wrote:
Hi Naomi,

The amount of time your collect N2O in your first trap depends on the flow rate while sparging the sample vial. You can check if your sparge time is long enough by repeatedly collecting from the same sample vial. You should also consider whether or not to bubble. Bubblers place their needle below the liquid level so that the carrier gas strips the dissolved N2O from the media / sample. Non bubblers leave the needle above the liquid level, probably do not gather all of the N2O, and run standards to account for that fact.

As Callum suggested, McIllvin and Casciotti 2011 have some great tips (e.g. needle design and septa).

andy

On Sun, Sep 2, 2018 at 7:49 PM Naomi Geeraert <[log in to unmask]> wrote:

Dear all,


We have just set up our Gasbench to do the denitrifier method for nitrate analysis in water. I would like to know from other users of this method how long they keep the LN-traps down. Is there a way to test after how much flushing time all the sample is retrieved? Right now, our method takes 30 minutes per sample, but that seems pretty long.


Any other advice/mistakes to avoid are also much appreciated.


Cheers,
Naomi


Dr.  Naomi Geeraert
Swire Institute of Marine Science
The University of Hong Kong
Kadoorie Biological Sciences Building
Pokfulam Road, Hong Kong, PRC
[log in to unmask]

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Sebastian Kopf
Assistant Professor
Geomicrobial Physiology Lab
University of Colorado Boulder
Department of Geological Sciences
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+1 (303) 735-6207