Martin,
       We have analyzed over 1000 water samples last year using a slightly
modified version of Rick Socki's method. We used both Venoject and
Vacutainers (non-silicone coated, 7 ml) with no problems. We even re-used
some of them after greasing the stoppers with Apiezon vacuum grease.
        We equilibrate 2 ml samples overnight at 25C without shaking. We
did some tests to determine minimum equilibration time and the results
showed that 3 hours is sufficient even without shaking if the Vacutainers
lie on their side.
        As Rick already mentioned, the problem that you are having with the
carbonate samples is probably caused by the temperature (50C). You
shouldn't have any troubles with your water samples.

Cheers,
Andrea


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|    Dr. Andrea Lini           |  Stable Isotope Laboratory    |
|    Department of Geology     |  Phone: (802) 656 02 45       |
|    University of Vermont     |  Fax:   (802) 656 00 45       |
|    Burlington, VT 05405      |  E-mail:[log in to unmask]     |
|    U.S.A.                    |  ISOGEOCHEM  list-owner       |
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