Hi all
    In the 12 years I've been working here no one ever asked to do 
N-15.   Well odds were against me.  Someone asked.
    The materials are plant samples where the 14N/15N ratios are to 
be determined at natural abundances.  The samples are from a growth 
chamber.
     Instead of reinventing the wheel, or finding the blueprints for 
it, I am looking for the following info.
     I have a Carlo-Erba with an off line prep system to capture the 
effluents. I am presently using it for 13C and 34S. I know about
the Keljall prep methods, but I am not equiped for it.  What I would 
like is to find a way to trap the N2 in a sample holder from the Erba 
to take to the MS. I've heard of someone using a molecular sieve, but 
I have no idea what materials are used.  Any info would be greatly 
appreciated.
    Also what is the best way to calibrate (ref gas, standards)????

Gilles
Gilles St-Jean, U. d'Ottawa / Geologie
140 Louis Pasteur, Ottawa, Ontario, Canada, K1N 6N5
Tel: 613 562-5800 ext: 6839(Bureau / Office)
     613 562-5800 ext: 6836(Lab)
Fax: 613 562-5192