Paul

I see that Willi Brand has responded to your query with news that
Linde supply H2 with a dD value of -220 per mil.

A few years ago Willi organised a 'ring test' (via Isogeochem) of
hydrogen gas samples supplied by Messer Griesheim. One of these
(ISO-TOP Ring-test Gas-A) has a dD value very close to SMOW, and we
have been using this (the cylinder contains about 1 litre at 12 bars)
ever since as our reference.

Willi - is this gas still available?

Tim Heaton

NERC Isotope Geosciences Laboratory
British Geological Survey
Keyworth, Nottingham NG12 5GG, England

Tel. +44(0)115 936 3401
Fax +44(0)115 936 3302
E-mail: [log in to unmask]