Simon,
are you adding V2O5 to your samples? you should add 1-2 mg as a combustion
additive.
Cyndi
**************************************************************
Cyndi Kester
Ecologist--Stable Isotope Lab
U.S. Geological Survey
Denver Federal Center, Bldg. 21, MS 963
Denver, Colorado 80225
office: 303-236-0278
lab: 303-236-7694
fax: 303-236-4930
email: [log in to unmask]
----------
>From: Simon Poulson <[log in to unmask]>
>To: [log in to unmask]
>Subject: d34S of BaSO4 by EA
>Date: Thu, Feb 1, 2001, 9:44 AM
>
> Hello everyone,
>
> As there's a small S conversation going on, I thought I'd ask if anyone
> might have any suggestions as to how to analyse d34S of BaSO4 by elemental
> analysis? I find that I often get very variable yields of SO2, which I
> think is due to inconsistent heating of BaSO4 during Sn combustion, and
> hence incomplete decomposition of BaSO4. I've tried a couple of things to
> try and increase the temperature/duration of the Sn combustion (e.g. using
> a larger Sn cup, using two Sn cups, adding PbO or sucrose, etc.), and this
> helps, but doesn't completely solve the problem. I'm currently using a
> single quartz tube at 1000 C - has anyone tried using a double tube
> configuration with an alumina tube at higher temperature (1300+ C) for the
> combustion, and then a quartz tube with Cu at 1000 C? Alternatively, has
> anyone identified an effective additive to promote complete BaSO4
> decomposition?
>
> Thanks in advance for any help or suggestions.
>
> Cheers,
> Simon
>
> *****
> Simon R. Poulson
> Dept. of Geological Sciences, MS-172
> University of Nevada-Reno
> Reno, NV 89557-0138
> USA
> Phone: (775) 784-1104
> Fax: (775) 784-1833
> [log in to unmask]
> *****
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