Paul,

What works for us is to decalcify with 2M HCl and then dry the residue on a
hot
plate on low setting overnite.  If you try and run this product in the EA, it
commonly rehydrates leaving a gooey mess.  So we then add a couple of ml of DI
water and freeze dry the sample, that leaves a nice fluffy product that can be
put in boats and dropped into the EA.  We are doing this on clam shells, have
not tried it with sediment at this point, but it should work.  What appears to
be impotant is not to wash the sample with water to remove the Cl prior to
isotopic analysis.  We tried phosphoric acid and it would not dry or freeze
dry.

Good luck,
Bill


At 12:34 PM 5/7/2001 +1000, you wrote:

>
> Would Phosphoric acid help you?
>
> -----Original Message-----
> From: Paul Brooks
> [<mailto:[log in to unmask]>mailto:[log in to unmask]]
> Sent: Wednesday, 2 May 2001 7:47
> To: [log in to unmask]
> Subject: Re: [ISOGEOCHEM] soil carbonate removal
>
> Dear list members,
>
> I have just had a query from some one preparing soils for 15N and 13C
> analysis by CN analyzer/IRMS.  They want to remove carbonate prior to
> analysis.  Does the addition of HCl work, or does leave so much HCl residue
> that Cl becomes a problem in the combustino tube?  Is there an accepted
> published method?  I seem to recall one method using HCl vapor instead of
> the acid directly on the soil itself, but I cannot find the reference.
>
> Thanks in advance,
>
> Paul Brooks.
>
>
> Paul D. Brooks,
> Dept. ESPM-ES,
> 147 Higard Hall MC 3110,
> UC Berkeley, Ca. 94720-3110.
>
> phone (510)643-1748,
> FAX (510)643-5098.



William J. Showers
Dept of Marine, Earth & Atm Sciences
North Carolina State University
Raleigh NC 27695

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