Martin Kennedy or others interested:

        I use "Venoject" brand 7cc vials w/ non-silicone coating for water-
carbon dioxide equilibration, and have been for 5 years with fine results.
Equilibration (using 1.4-1.5cc water sample) is done at 25C for at least 90
min.(when shaking) (see Socki, et al. 1992, Anal. Chem. 64, 829-831 for
details). Typically I set up 18-20 samples in the afternoon and extract them
the next morning.

        As far as leaks go, I suspect 50C is too hot for the vacutainer stopper
to seal properly.

Cheers,
Rick Socki
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