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Peter,
You should add a cm of silver wool in the end of your combustion tube.
That will hold the sulphur.
By the way: I think your computer is a day behind.
regards,
Arnold

Peter Vervloedt wrote:
>
> Dear Listmembers,
>
> I need some help on the following:
>
> We extracted soils with K2SO4 (0,125M, 50mL), and then freeze dried those
> samples in tin cups. It was the first time we used this technique and didn't
> realise the danger.
>
> Apparantly the very high sulfur-content in the cups causes serious
> contamination of the GC (we use Anca-SL), when measuring the samples for
> 13C.
>
> Are there any of you that have experienced the same problem? Is there a way
> to modify the equipment (to scrub out the sulfur), or is there another way
> to get rid of the sulfur?
>
> Thanks a lot in advance!
>
> Best regards,
>
> Peter
>
> ---
> Peter Vervloedt
> Laboratory Of Applied Physical Chemistry
> Ghent University
> Coupure 653
> 9000 Gent
>
> tel.: +32 9 264 6000
>        +32 9 264 6048
> fax.: +32 9 264 6230
> ---
> -----Oorspronkelijk bericht-----
> Van: Stable Isotope Geochemistry <[log in to unmask]>
> Aan: [log in to unmask] <[log in to unmask]>
> Datum: vrijdag 20 oktober 2000 9:06
> Onderwerp: Re: [ISOGEOCHEM] Isotopic
> carbonatealterationduetothermaltreatment?
>
> Micha,
>
> depending on the water content and the presence of metastable carbonate
> phases in the core there may be transformation of the carbonate fraction
> into
> more stable phases. Depending on a number of boundary conditions O isotope
> exchange may occur. This will probably be not a serious problem for C
> isotopes. During roasting some OM will decompose and create CO2.
>
> Regards, Michael
>
> Micha Horacek wrote:
>
> > Dear isogeochemists,
> >
> > I think I have to formulate my request more precisely:
> >
> > The palmag cores are demagnetised by heating to temperatures above 350 C
> > for at least two hours (but I do not think much longer) and "roasted" at
> > maximum temperature of 500 for twenty minutes.
> > The cores consist of massive rock, not powder. The cores are from impure
> > carbonate rocks with low organic contents.
> > Can the demagnetisation process possibly change the isotope ratios, for
> > example if the carbonate content of the sample is rather small?
> >
> > Cheers,
> > Micha