Greg,

You may find the idea in Holt & Engelkeimer (1970) Anal. Chem. 42, 1451-1453
and perhaps also in vol.1 edited by Pier de Groot.
The method bases on reliable delta-66 and delta-50 measurements in SO2
prepared by thermal decomposition of BaSO4. However in my opinion it is
hard to avoid oxygen isotope exchange with nearly soft quartz (T=1500oC)
used for reactor. The expected precision is ca. 10 times lower than in CO2
analysis.
Perhaps Roy Krouse will add a comment.

Greetings to All,
Stan


At 19:16 04-11-29 -0800, you wrote:
>Is anyone familiar with the sulfate 18O analysis technique of Van Stepvoort
>and Krouse?  In the literature Ive found discussions about SiO2/V2O5
>conversion to SO2.  Im assuming the oxygens are all exchanged during this
>reaction and this is the means to get the 34S number, but its unclear where
>the 18O numbers are coming from.  Im assuming its graphite reduction to CO2
>or CO but I can not find that explicitly stated in any of the papers.  Are
>there any references to the 18O aspect other than Van Stepvoort's PhD thesis?
>
>Greg Michalski
>Stable Isotope Lab, 5108 Urey Hall
>University of California, San Diego
>9500 Gilman Dr.
>La Jolla, Ca. 92093-0356
>858-534-6053

Dr. Stanislaw Halas
Mass Spectrometry Laboratory
Institute of Physics, UMCS
20-031 Lublin, Poland
phone: +48 81 537-62-75
fax: +48 81 533-36-69