Pauline et al.

We had HPDE containers from Nalgene that we had tested for diffusion
effects.  The company neglected to mention that the interior diameter had
at some point been increased, while the exterior diameter remained the
same.  Part numbers and specifications listed were all identical.  It
turned out that the new bottles were too thin -- less than 2 mm as I
recall -- and significant diffusion occurred.  We never worked out a
diffusion rate vs. thickness but I think this could be easily done from
the data.

These problems are discussed in Stuiver, M., P.M. Grootes, and T.F.
Braziunas. 1995. The GISP2 18O climate record of the past 16,500 years and
the role of the sun, ocean and volcanoes. Quaternary Research 44:341-354.

You might also try contacting Travis Saling ([log in to unmask]) about
the details.

Eric Steig

________________________________________________________________________
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Department of Earth & Environmental Science  tel: 215/898-9890 lab
University of Pennsylvania                   FAX: 215/898-0964
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On Fri, 10 Sep 1999, Pauline Treble wrote:

> Greetings listmembers,
>
> I'm collecting cave water samples for D/H and del-18 analysis. I wanted to
> know if anyone could offer any advice regarding HDPE plastic storage
> containers. The samples would be collected over a month and stored in HDPE
> drums under a good few cm's of paraffin oil prior to more satisfactory
> storage in glass bottles.
>
> I have the option of using drums with either 2 mm or 6 mm wall thicknesses.
> Since there is a LARGE difference in price between the two drums, I wanted
> to know if anyone could offer any advice on the minimal wall thickness that
> could be used while still avoiding diffusion through the plastic?
>
> Thanking you,
>
> Pauline.
>