Dear Rebecca:

The number of laboratories analyzing 18O/16O ratios of dissolved nitrate is
constantly increasing. Since several years, this analytical technique is
successfully used at the University of Waterloo (Canada, contact Bob
Drimmie, Ramon Aravena, or. S. Schiff), at the NHRI in Saskatoon (contact
Len Wassenaar), at the University of Calgary (see address below), and at
the USGS in Menlo Park, California (contact Carol Kendall), among other
laboratories. To the best of my knowledge, most of these groups use a
preparation technique, which converts dissolved nitrate into AgNO3 (see
Wassenaar, 1995, Appl. Geochem. and Silva et al. submitted to J. Hydrol.
for further details). There are numerous potential pitfalls dependent on
the nature of your samples. For isntance, high DOC contents and high
salinities can pose serious problems.

Best wishes,

Bernhard

Bernhard Mayer
Stable Isotope Laboratory
University of Calgary
Calgary, Alberta, Canada T2N 1N4

-----Original Message-----
From:   Rebecca Hood [SMTP:[log in to unmask]]
Sent:   Wednesday, August 04, 1999 4:09 AM
To:     [log in to unmask]
Subject:        16O-18O ratios of nitrate

Who out there is out there doing 16O-18O ratios on nitrate? if so what's
the
latest technique and easiest ?

Someone asked me for this information, as we don't do it here yet  I would
be interested to find out how and what are the pitfalls.
Samples they are thinking of are soil-water samples, at natural abundance
levels. It has some interesting potential....

I would be most grateful for all suggestions, comments, references etc...

Thanks in advance for any assistance........
Long live isogeochem....

Rebecca Hood