Juzhi Hou,

Some pinhole leaks are not easily seen even with a light microscope.

I have had similar problems with quartz and Pyrex glass stock items over
the last twenty years.

If the manufacturer/fabricator gets sloppy or careless, you pay the price.

Also, the quartz reactor tubes do start cracking with use. We have seen
this here. So far, we have not had your problem with gas leaks.

Glen Martin





                      Juzhi Hou
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                      Sent by: Stable          Subject:  a problem on GC-C-IRMS hydrogen reactor
                      Isotope
                      Geochemistry
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                      11/12/04 02:25 PM
                      Please respond to
                      Stable Isotope
                      Geochemistry






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