HI Kim--

I think you hit the nail on the head....reduction column probably used 
up, so you're seeing NO, and it's landing in your most sensitive 
detector, so it goes off scale quickly.

take care

gerry

Kim Baublys wrote:

> Hi Everyone,
>
> Does anyone have experience in doing nitrogen on RNA or DNA?  I have 
> run DNA samples for carbon with no problems but the Nitrogen is 
> proving problematic and I freely admit that I haven't a clue and that 
> I am hoping that someone can provide a 'quick fix' :)
>
> I am using an Isoprime with a Carlo Erba EA.  The problem is that my 
> 28 peak was only 5X10-10 Amps while the detector for mass 30 was 
> swamped and there still appears to be mass 30 coming from the EA.  
> Never having run RNA for nitrogen is it possible that the combustion 
> was not complete and that I am getting NO?  What other species could 
> it be?  I wouldn't have thought it would be hard to combust properly.  
> (I will be checking my reduction tube tomorrow morning just in case 
> something has gone wrong there)
>
> Any suggestions on the analysis would be appreciated plus 
> recommendations on which papers to read.
>
> Thanks
> Kim
>
>
>
> Kim Baublys
> Stable Isotope Laboratories
> Department Of Earth Sciences
> University of Queensland 4072
> Australia
>
> Ph:   +61 7 3365 1131
> Fax: +61 7 3365 1277
> http://www.uq.edu.au/geochem/
>