Dear Patrick Dauby,

We were also performing the D/H analysis in water with sealing water 
sample and zinc in pyrex tube. We also observed that there was on 
hydrogen in the tube after leaving the sealed tube for sometime. 

In our opinion you are right that the diffussion of hydrogen from pyrex 
tube may not be so high. As we were having our hydrogen standards for 
more than year in pyrex tube without any alterations. We suspect the 
possible reason for it could be  the formation of Zn(OH)2. We never made 
any analysis of remaining zinc shot. 

I wish it could be of some help.


Best regards


Mahendra
   

Patrick Dauby wrote:
> 
> Dear friends,
> 
> I regularly receive samples of water in vacuum-sealed pyrex tubes
> furnace-combusted with zinc shots for D/H analysis.
> As I am not only doing such type of measurement, I often cannot perform
> analyses immediately.
> So I'd like to know whether these samples can be conserved for a while or
> not. May someone of you provide me with references on the subject? I
> personnaly cannot imagine hydrogen gas to diffuse through an amorphous
> glass wall. But I was told by colleagues of me that D (preferentially to H)
> could do bonds with SiO2 and thus induce fractionation.
> Thanks for advices and help.
> 
> Pat
> 
> __________________________________________________________
> 
> Patrick DAUBY
> Universite de Liège
> Laboratoire d'Océanologie
> Unité de Recherche en Biogéochimie des Isotopes Stables (URBIS)
> B6 Sart Tilman
> B-4000 Liège, Belgium
> Phone: +32.4.3663322  -  3663307
> Fax: +32.4.3663325
> Beep: 0454.700.671 (inside Benelux only)
> WWW: http://www.ulg.ac.be/oceanbio/urbis.htm
> __________________________________________________________