Paul,
I assume you need a tank of hydrogen gas that is not depleted by
something like 75% as hydrogen gas normally is when produced by
electrolysis. With Linde AG (Leuna, Germany) we have a source of
hydrogen gas that manufactures from natural gas. It's isotopic
composition is at -220 per mill on the VSMOW scale. So, you should ask
the hydrogen gas supplier whether the gas production is electrolysis or
natural gas. Good luck.    Willi

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Willi A. Brand, Stable Isotope Laboratory       [log in to unmask]
Max-Planck-Institute for Biogeochemistry
Tatzendpromenade 1a, 07745 Jena, Germany        Tel   +49-3641-643718
P.O.Box 100164, 07701 Jena, Germany             Fax:  +49-3641-643710
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