Bill,

I am very much interested about your technique.  Could you pleas send me
a copy of your paper as soon as it is accepted?  It sounds like you used
the same idea that we used and worked for us very well (Revesz and
others "Determination of delta O-18 and N-15 in nitrate" Anal.Chem.
1997, 69.), namely we found a temperature range where there was
equilibrium between the two reaction products CO2 and K2CO3.  So it is
enough to analyze the O-18 in the CO2, the rest can be calculated.  I
like your approach very very much, and I would like to try it.  Thanks.
Kinga Revesz

William Buhay wrote:
>
> Barbara, (and others interested)
>
> Neil Loader and I felt it was ultimately best to "feed" Mass Spectrometers
> what they were made for, CO2 rather than CO (thus avoiding all the problems
> associated with using CO).
>
> Measuring CO2 rather than CO came as a necessity to Neil and I initially
> since the Prism and Sira at the GIQR (Cambridge) are utilized regularly for
> CO2 applications (leaving us no chance to try CO applications).
>
> Based on my work with nickel pyrolysis bombs I anticipated that there was a
> possibility of equilibrating CO and CO2 on-line within the right temperature
> range (which eventually turned out to be true).
>
> There really isn't any detour involved in our technique. As in CO
> techniques, our pyrolysis products also pass through the reduction oven,
> however, ours is filled with nickel powder at a temperature set between 500
> and 600 C.
>
> I guess our technique would be of most interest to those who don't have the
> luxury of dedicating a MS soely to CO applications. It seems like a hassle
> (at least to me) to keep converting your MS back and forth between CO and
> CO2.
>
> The proof for our paper (in press: Rapid Communications in Mass
> Spectrometry) has just been mailed in so it should be out sometime this
> fall.
>
> As an additional note: when running organic materials, hydrogen is separated
> off from the main flow through a membrane. This  provides the possibility of
> running hydrogen isotopes using this technique in the future.
>
> cheers, Bill
>
> ----- Original Message -----
> From: Barbara Kornexl <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, August 05, 1999 7:50 AM
> Subject: Re: 16O-18O ratios of nitrate - production of CO2
>
> > Bill,
> > I just wonder why you go on this detour and produce CO2 as a measuring
> > gas... I checked with Rapid Commun Mass Spectrom but couldn't find your
> > paper yet. Maybe you can explain shortly.
> > Thanks
> >
> > Barbara
> >
> > ****************************************************************
> > Dr. Barbara E. Kornexl
> > UFZ - Umweltforschungzentrum Leipzig-Halle GmbH
> > Sektion Analytik
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> >
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> >