Dear Dennis and others,

I'm currently in the process of trying to arrange for direct shipment of a
CO tank from BOC in the UK to the US.  As far as I can tell, CO from the UK
typically has a "normal" isotopic abundance, like gas from Germany.  I've
gotten a quote of 88 pounds sterling for 1.7 cubic metres of CO, purity
99.9%.  We have to purchase the gas cylinder outright (another 150 pounds
sterling), but BOC tells me that they will re-fill the tank in the future,
as needed.  Right now I'm waiting for a quote for shipping by surface
freight, as the price for shipping by air freight is expensive (245 pounds
sterling, and even then that's only to San Francisco, not Reno).

As an aside, I was wondering if anybody had any thoughts as to whether very
high purity CO is necessary, i.e. a purity better than 99.9%.  I've used a
small tank of CO with purity 99.5% and a very light isotopic composition,
and was finding that I could get what I thought was acceptable
reproducibility, with a standard deviation of d18O of 0.2 per mil (or
slightly better), which makes me think that very high purity CO is
unnecessary.

Cheers,
Simon

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Simon R. Poulson
Dept. of Geological Sciences, MS-172
University of Nevada-Reno
Reno, NV 89557-0138
USA
Phone: (775) 784-1104
Fax: (775) 784-1833
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