Stable Isotope Geochemistry


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Zachary Sharp <[log in to unmask]>
Reply To:
Stable Isotope Geochemistry <[log in to unmask]>
Mon, 23 Feb 2004 07:17:02 -0600
text/plain (71 lines)
Dear Carolyn,

We did this a long time ago with very good success.  We made a pellet out
of AgPO4 and a huge excess of graphite.  Our products were CO and CO2, so
that we had to convert the CO back to CO2.  If this were to be done today
in a He flow, perhaps with less C, the products might be much more CO2 and
less CO, although this could still be a problem.

Z.D. Sharp and J.R. O'Neil, A laser-based carbon reduction technique for
oxygen isotope analysis of silicates and oxides., Carnegie Inst. Washington
Yearbk 21, 72-78, 1989.



At 03:37 AM 2/23/2004, you wrote:
>I tried this some years ago and the results were a mess, poor O2 yields,
>and very poor values.  I used ClF3 and the residue was like solidified tar
>( we didn't bother to analyse it though).
>Has anyone tried a laser without a fluorinating reagent on Ag3PO4 mixed
>with graphite ?
>[Chenery, Carolyn A]  -----Original Message-----
>From: Sandro Meli [mailto:[log in to unmask]]
>Sent: 20 February 2004 14:51
>To: [log in to unmask]
>Subject: [ISOGEOCHEM] silver phosphate reaction with CO2 laser
>fluorination technique
>Dear listmembers,
>I'm trying to react silver phosphate, chemically precipitated from organic
>stuff (bones and teeth, mainly), in a laser fluorination line. I'm
>employing a CO2 laser (10.66 mm) and BrF5 as reagent. Until now, I never
>got a satisfying oxygen yield, being always lower than 90%.  Does anyone
>have any experience about the laser fluorination technique applied to
>silver phosphate? Does anyone know which are the residues of such
>reaction? At present I've found in the literature a couple of recent
>papers about its application on apatites, but nothing on silver phosphate.
>Thank you in advance
>Sandro Meli
>Sandro Meli Ph.D.
>Dip. Scienze della Terra
>UniversitÓ di Parma
>Parco Area delle Scienze 157/a
>43100 - Parma
>Tel. +39-0521-905376
>Fax. +39-0521-905305
>e-mail: [log in to unmask]
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