It's either that (NO formation and exhausted reduction tube) or your machine
has drifted away from the original tune parameters so cup 1 now samples the
flank of either m/z 28 or m/z 29 and cup 3 collecting predominantly m/z 29.
Cheers,
Wolfram
> -----Original Message-----
> From: Stable Isotope Geochemistry
> [mailto:[log in to unmask]] On Behalf Of Kim Baublys
> Sent: 04 October 2005 05:51
> To: [log in to unmask]
> Subject: Puzzle: SIRMS of N in RNA
>
>
> 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/
>