Dear Kim,
In your message to Isogeochem you say

"We have found reference to such a standard in a paper by
L. Ayliffe et al. The standard they used was supplied by a Y. Kolodny".

Here is the above responding. The standard we here, Linda Ayliffe,  Bill Showers
from the Univ. of South Carolina, as well as several others (J. O'Neil,
H.Schwarcz, L.Roe...),  used is NIST standard phosphate NBS-120b. We got a best
value for that of 20.5 permil, using BiPO4. Jim O'Neil used NBS-120c and got a
set of values around 23.1, using a AgPO4 precipitate. Bill Showers also used
AgPO4, and obtained somewhat heavier numbers than we did. I suspect the true
value is somewhat heavier than ours, most people who run our BiPO4 got about 0.5
permil heavier than we did.
It seems there are many advantages to running AgPO4.
Currently we here are not analyzing phosphate; much work is being done by ONeil
at the Univ. of Michigan.
We do have some standards left, that includes NBS-120b, as well as a KHPO4
standard, and possibly the BiPO4 derivatives from that. We alos have so KP-64
which is sometimes quoted in the literature. Let me know when you want specific
items.
For more on methods see
O'Neil et al. 1994, A rapid and precise method of oxygen isotope analysis in
biogenic phosphate: Isr. Jour. Earth Sci. 43:203-212.
Also: Crowson et al. 1991, Anal. Chem.63: 2397-2400.
and references in both.
When referring to delta 18O as del, please remember the limeric by H. Craig
which was also distributed on this users list:

There was a young man from Cornell
Who pronounced every "delta" as "del"
But the spirit of Urey
Returned in a fury
And transferred that fellow to hell
regards
yehoshua




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Yehoshua Kolodny,
Dept of Geology, The Hebrew University . Jerusalem. ISRAEL 91904
PHONES: off:(972) 2-6584685; dept.:2-6584686; home 2-5636879;FAX:(972-2) 662581
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