Kim,

For NBS-127 d18O = +9.3%o vs. VSMOW was used in laboratories by far, but 
with advent of on-line technique it was found that this value is ca. 0.5%o 
too high, see eg. Boschetti & Iacumin, Rapid Comm. in MS, 2005, vol.19, 
pp.3007-3014.
Other 2 reference materials are IAEA SO-5 and SO-6 calibrated on-line, see
Bohlke, Mroczkowsi and Coplen, ibid. 3003, vol. 17, pp. 1835-1846.

Soon my lab will finish their calibration by off-line approach.

Stan


At 15:30 06-05-24 +1000, you wrote:
>Hi Everyone,
>
>Given that sulfate oxygen has been mentioned lately, I too have a question.
>
>We have recently been looking at sulfate oxygens and are wondering if 
>there a recognized oxygen value for the sulfate standard NBS127?
>
>Also, what other standards exist if any for sulfate oxygen?
>
>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/

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