Hi Matt,

We have an internal standard here for bioapatite called MEme (for
MacFadden's Elephas maximus enamel). We have run several hundred analyses
of the CO3 fraction of the apatite (d18O ~25.7) and soon expect to measure
d18O from the phosphate.

We don't have a ton of material, but enough to make using MEme worthwhile
as an internal standard for tooth enamel samples in our lab for the next
decade or so.

If you, or anyone else on this list, would like a small sample of MEme to
try out, let me know. I will send you information about how the standard
was developed and how we know its isotopic values. All we ask for in return
is a report on the values for MEme you get. We would like to have other
labs do some replicate analyses, so we might compare inter-lab,
inter-instrument values.

Cheers,

Penny

At 09:53 AM 12/2/2003 -0500, you wrote:
>Hi,
>
>I'm looking for oxygen isotope standards for the CO3 component of
>biogenic phosphates. I've been running NBS-120c, and getting ~28.2
>+/- 0.1 permil (V-SMOW), so it seems reasonably homogeneous (at least
>for a couple mg-sized samples). But firstly, I don't know of any
>publications that have reported a value for the CO3 component in
>phosphate from NBS-120c, so I don't have an independent check on our
>value via other labs. And secondly, I'd prefer a lower d18O standard
>in addition to NBS-120c. Naturally, we have plenty of carbonate
>standards that we also run. But if there's a phosphate standard out
>there, I'd like to know about it.
>
>Any thoughts on the value for NBS-120c CO3 component and on
>alternative phosphate standards are much appreciated.
>
>Matt
>
>--
>
>
>********************************************
>Dr. Matthew J. Kohn, Assistant Professor
>Dept. of Geological Sciences
>701 Sumter St., Room EWS 617
>University of South Carolina
>Columbia, SC 29208
>phone: (803)-777-5565   fax:(803)-777-6610
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>http://www.geol.sc.edu/kohn/index.htm
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