Dear all,
we have just discussed cleaning and re-using the Cr-filled quartz reactors
for the Finnigan H/Device. In our opinion, and we have a lot of experience
in using Cr for H/D measurements, the H-device reactors are used only once.
We do not recycle chromium by special chemical treatment because of
changing the internal surface, reaction surface and possible other
impurities. At the beginning to work with the H-device, Reiner (a colleague
of our group) tried to recycle the reactor by several mechanical and magic
tricks. The sintered Cr is too hard for removing out of the reactor. And
now, we do not use quartz chips for the quartz reactor of the H-device.
 However, as Willi Brand wrote, doing a number of samples, it will reduce
the costs per sample. And it seems to much more cheaper than all chemical
treatments to save the Cr or the reactor.
In the past, we mixed the Cr powder with quartz chips in order to clean up
the reaction tube. However, the tube was shaped like a real tube, and we
could remove the sintered Cr with a strong wire (mechanically). It worked
for our off-line Cr reactor.
Regards from the Halle's Isogroup
Gerhard
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