Hi,
First, I would like to apologize for posting this request on this
listserv.  Normally I would look up the answer in the library, but I
am in Barbados for a month and access to scientific literature.
I do my work on a Europa Single Inlet Mass Spec and obtains good result 
for N-15 ratios for animal tissues.  I would like to isolate enough 
nitrate from ground waters here on the island to test for some
human waste origin (which can be as high as 20 o/oo).  My question is:
How can this be done.  Does anbody know of a recipe?  I figure that 
I need about 50 mg N for it to work on the Europa.

Thank you for your time,
                                      Gilbert Cabana
                                        Ph.D. Candidate
                                       McGill University