Dear All,
        One of my graduate students needs to analyze d15N of NH4+ dissolved
in lake water. We have tried to obtain some of the same zeolite (Union
Carbide ION-SIV W-85) used by other investigators (Lipschultz et al. 85,
86; Velinsky et al. 89, Gu and Alexander 93) for similar studies but UC
stopped production of this particular zeolite a long time ago and
apparently they have none left. Does anybody have a few spare grams of UC
W-85 for sale? Or, can anybody suggest an alternative zeolite which can be
used to trap ammonium or an alternative (and not too painful...) method for
extracting NH4+ from lake water? We are dealing with very low NH4+
concentrations (<5 microM/liter).
Thank you very much!

Andrea


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|    Dr. Andrea Lini           |  Stable Isotope Laboratory    |
|    Department of Geology     |  Phone: (802) 656 02 45       |
|    University of Vermont     |  Fax:   (802) 656 00 45       |
|    Burlington, VT 05405      |  E-mail:[log in to unmask]     |
|    U.S.A.                    |  ISOGEOCHEM  list-owner       |
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| ISOGEOCHEM URL: http://beluga.uvm.edu/geowww/isogeochem.html |
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