Hello Jane,

I remember that the late Tom Hoering at the Carnegie Institution had great
success in using simple electrolysis (DC applied to graphite electrodes)
in a large reservoir of slightly acidified water in a
sealed Pyrex round flask with attached stopcock.  Electrolysis of water
produces D-depleted hydrogen gas, so Tom had added just the right amount
of D-enriched water to obtain hydrogen gas "at the push of a switch" with
a deltaD value around zero.  I understand that he had to pass the wet
hydrogen through a cold trap before using it at the mass-spec.

This method seemed to be very reliable and low-cost.

                                         Best wishes,      Arndt
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Arndt Schimmelmann
Biogeochemical Laboratories
Indiana University
Department of Geological Sciences
1005 East Tenth Street
Bloomington, IN 47405-1403
U.S.A.
ph 812-855-0154
ph 812-855-7645
fax 812-855-7961
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