Dear All,

I will be working in Jamaica this summer to look at 15N in plant-soil 
systems.  I will be measuring 15N of bulk soil which will be 
straightforward but I am also hoping to measure 15N of ammonium and 
nitrate (which are the forms of nitrogen that will be immediately 
available to plants and are therefore of more interest).  Does anyone know 
of a method which can be used to measure 15N of these two compounds.  

The main drawback I have is that I'll be in Jamaica while our IRMS is in 
Dublin.  This means that I need to be able to process and/or store the 
samples for a few weeks before being able to analyse them.  Also, I won't 
really have access to a lab so the easier and simpler the method the 
better.

Many thanks

Francis