Help: Tritium Gas retrieval bags from Aldrich

Randy Willis willis at gandalf.psf.sickkids.on.ca
Thu May 8 10:04:57 EST 1997


Hello all,
  I'm new to the chem newsgroups and am posting this for a friend.  If
you can give him assistance, please send the info directly to him as he
does not have access to any newsgroups, although I will try to keep an
eye on the groups for the sake of forwarding the info myself...thanx. 


  I will be performing a labelling reaction.  On of the by-products
of this reaction is radioacive hydrogen.  I have been trying to come up
with ways of trapping this hydrogen as the Radiation Authority is a
little antsy about releasing that much activity up the stacks.  I have
talked to the appropriate people (e.g. Tritium Recovery Program at
Darlington Nuclear Power Plant, Slowpoke Reactor at The University of
Alberta and believe me, a slew of others) about trapping the hydrogen on
some metal or converting it to radioactive water using some catalyst. 
To make a long story short, neither trapping or conversion is
appropriate for one major reason; as a medical faculty, we just don't
have the "industrial strength" facilities for these kinds of procedures
(cryogenic distillation of hydrogen at 20K, requirement of vacuums
100-1000X better than what our lyophilizer pumps can deliver).  Besides
which, I'm only talking about a couple of hundred microlitres in
volume.  (In case you're wondering, activated carbon is a-ok for
sulphide gas, but an absolute dud vis a vis hydrogen gas.)
        According to Aldrich though, I could use gas bags made of heavy 
natural rubber  (Cat. No. Z18,674-0).  I've called the importer of 
these bags, Walter Stern Inc..  Although they confirm that indeed, these 
bags ARE impervious to hydrogen gas, they won't divulge where they get 
the bags.  Thus, my search for technical information about these bags
has  been temporarily stymied.

Q:  Does anybody know where I could find some technical information
about the permeability of hydrogen gas through gas bags made of heavy
natural rubber?  A search on the Web has thus far produced NASA and Los 
Alamos safety manuals on hydrogen fuel used in jet propulsion!


Thank you for your assistance, 

Joe Papalia, University of Toronto

joe at lec.med.utoronto.ca



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