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