Dear Bernhard and all others,

Bernard, I would certainly appreciate it a lot if you could spare us some
of your pine tree bark sample.

To all of you:
-Who would be interested in having a few different plant material sulfur
SRMs ? Could we organize the production and certification of such a
material through this list ?
-Does anybody know the address of Brian Fry, because I would be interested
to here what he has to say about the oxygen correction for SO2 measurement
(see below).

To all CF-IRMS users:
Is anybody working on validation of CF-IRMS for sulfur isotopic analysis of
plant material or other S containing organic compounds?

With Best Regards

Anders Ohlsson


At 08:14 1999-07-30 -0600, you wrote:
>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

==============================================================
K.E.Anders Ohlsson
PhD, Researcher
Address:  Department of Forest Ecology, Swedish University of Agricultural
Sciences,
Petrus Laestadius väg, SE-901 83 Umeå, SWEDEN

phone +46 (0)90-786 5892
fax   +46 (0)90-786 7750
email:  [log in to unmask]
==============================================================