Dear Juzhi,
I had the same problem, and I was told (by Gilles StJean) that the reactor
is good only for 2 weeks if you keep it at  high temperature constantly,
after that it could become transparent.  So, it is good to turn the
temperature down to 900 C when the reactor is not used.
Kinga



Kinga Revesz
Chemist, Stable Isotope Laboratory
U.S.Geological Survey
MS 431
Reston, VA 20192
T:703-648-5865
FAX: 703-648-5274

http://www.isotopes.usgs.gov


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|         |           Juzhi Hou        |
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|         |           Sent by: Stable  |
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|         |           Geochemistry     |
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|         |           UVM.EDU>         |
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|         |           11/12/2004 03:25 |
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|         |           Please respond to|
|         |           Stable Isotope   |
|         |           Geochemistry     |
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  |       To:       [log in to unmask]                                                                                      |
  |       cc:                                                                                                                    |
  |       Subject:  a problem on GC-C-IRMS hydrogen reactor                                                                      |
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Dear list members,
I am working  on GC-C-IRMS to measure the dD of some compounds. I want
to ask a question on the Hydrogen reactor.
After a few days running, the leakage of the instrument is a little
higher (Mass39.8 is about 40 mV or a little higher). I could not find
leakage at any connectors. However, when I blow argon directly to the
hydrogen reactor in the GC oven, the leakage (mass 39.8) reachs ~100 to
200 mV. After we change the reactor,  no leakage is found(less than 20
mV). I could not find any cracks on the old reactor when I observe it in
microscope.
I was told this problem (cracking reactor) had never happened.
Has anyone found this problem ever?
Is the reactor really broken?
Thanks for any information!
Juzhi

--
Juzhi Hou
Graduate Student
Department of Geological Sciences
Brown University
Box 1846
Providence, RI 02912
1-401-225-4390