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    Dear all,

I'm looking for a good procerure to sererate ammonia and nitrate in
agricultural soils that have low concentrations of nitrogen in them. I'm
using a Carlo Erba nitrogen analyzer coupled to a Uropa Tracermass 20/20, I
would like to take a small volume of solution put it on chromosorb and
combust the sample for nitrogen isotope ratios if possible.

                       Thanks  Armand

--- end quoted text

In our lab, we use a diffusion method co-developed by my boss, John Stark.
I don't have a reference here at home, but I can get one for you at work.
The process involves extracting the N in 2 M KCl solution and then
filtering out the soil. The solution is then run on a colorimetric
analyzer for total NH4 and NO3. Then a certain amount is diffused with a
MgO catalyst and the NH4 is collected on acidified paper disks sealed in
PTFE tape. The solution is later diffussed for NO3 by adding Devarda's
alloy and collected on the same acidified paper disk trap. These disks are
run on our Europa 20/20 analyzer for 15N enrichement. If this is something
you are interested in, please let me know and I'll look up the reference
for the procedure and mail it to you.

Regards,

Myq Larson



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| Myq Larson | Stable Isotope Analysis | [log in to unmask]   |
|            | Utah State University   | 435.753.0753 (h) |
| Knowledge  | 5305 University Hill    | 435.797.0060 (w) |
| Liberates  | Logan  UT  84322-5305   | 435.797.1575 (f) |
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