Dear Anders:

In the Stable Isotope Laboratory at the University of Calgary, we have a
couple of ground pine tree bark samples, which we occasionally use to test
our sulfur CF-IRMS system. Total S contents of these samples range between
5 and 12% (!) and the d34S values are close to +22 per mil. Our supply of
these samples is limited, but we might be able to spare a few milligram, in
case you are interested.

Keep in mind that sulfur isotope analyses by CF-IRMS on plant material are
often complicated by the fact that S contents are typically around 0.1%,
while C contens are closer to 50%. Another problem, which is currently
unresolved for sulfur isotope analyses on plant material by CF-IRMS is the
oxygen isotope correction (contribution of 32S18O16O to mass 66 in case you
use SO2). The person closest to resolving this problem might be Brian Fry
(presumably in Louisiana these days). All I am saying is that you don't
necessarily need to blame your mass spectrometer, in case you obtain
erroneous results during sulfur isotope analyses on plant material by
CF-IRMS.

Good luck,

Bernhard

Bernhard Mayer
Stable Isotope Laboratory
University of Calgary
Calgary, Alberta, Canada T2N 1N4

-----Original Message-----
From:   Anders Ohlsson [SMTP:[log in to unmask]]
Sent:   Friday, July 30, 1999 2:41 AM
To:     [log in to unmask]
Subject:        Plant material Sulfur-SRM

Dear All,

What I need is a plant material Sulfur-SRM for 34S/32S determination. We
want to test the accuracy of the Continuous Flow (CF) -IRMS method for
sulfur when applied directly to plant materials. There seems to be no such
SRM issued by IAEA or NIST. Does anybody know of such material or if there
is some ongoing work to produce it ? Is there some recent study on
establishing the accuracy of CF-IRMS method for this analysis?

With Best Regards
Anders Ohlsson
======================================================
Anders Ohlsson, forskare, FD i analytisk kemi
Institutionen for Skogsekologi
Sveriges Lantbruksuniversitet (SLU)
901 83 Umea
tel. 090-786 5892
fax  090-786 7750   email:  [log in to unmask]
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