Diann,
Hope this helps....

                      TECHNIQUE                d18O   (n, standard deviation)

Robertson      mercury(II) chloride       32.14     (6, 0.20)
Switsur               mercury(II) chloride       32.7       (4, 0.13)
Yakir              mercury(II) chloride       31.4      (3, -)
Yakir              mercury(II) chloride       31.7      (3, -)
Buhay            nickel tube                   31.8       (6, 0.14)
Trimborn              nickel tube                   31.3      (5, 0.19)
Saurer           nickel tube                   32.20    (7, 0.11)
Saurer           continuous flow           32.52     (21, 0.33)

Refs

Buhay, W.M. and Edwards, T.W.D., Climate in southwestern Ontario, Canada, between AD 1610 and 1885 inferred from oxygen and hydrogen isotopic measurements of wood cellulose from trees in different hydrologic settings. Quaternary Research 44, 438-446, 1995.

Saurer, M., Robertson, I., Siegwolf, R. and Leuenberger, M., Oxygen isotope analysis of cellulose: an interlaboratory comparison.  Analytical Chemistry 70, 2074-2080, 1998.


Iain


----- Original Message -----
From: Diann Whitehead
To: [log in to unmask]
Sent: Thursday, April 05, 2001 8:30 PM
Subject: Data on cellulose standard for 18-O/16-O analysis


I'm looking for d18O data on the IAEA C3 cellulose standard since this is not published in their catalogue. I could also use the ANU sucrose as a primary std but there doesn't seem to be any data there either. I notice from the archives that this topic has been discussed at length. Does anyone have any values that I might use in confirming a secondary (working) standard? And has there been any progress on finding a cotton cellulose standard? We're planning to use the on-line pyrolysis method developed by Farquhar et al. (1997) A rapid on-line technique for determination of oxygen isotope composition of nitrogen-containing matter and water. Rapid Communications in Mass Spectrometry, Vol. 11, 1554-1560.  I hope to be able to verify the provenance of raw cotton cloth being imported into Canada since the country of origin has tariff implications. Has anyone done any work on this?


*********************************************
Dr Iain Robertson
Quaternary Dating Research Unit,
CSIR Environmentek, PO Box 395,
0001 Pretoria, SOUTH AFRICA.

Tel   + 27 12 841 2300
Fax  + 27 12 349 1170
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