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 |---------+----------------------------> | | Juzhi Hou | | | <[log in to unmask] | | EDU> | | | Sent by: Stable | | | Isotope | | | Geochemistry | | | <[log in to unmask] | | UVM.EDU> | | | | | | | | | 11/12/2004 03:25 | | | PM | | | Please respond to| | | Stable Isotope | | | Geochemistry | | | | |---------+----------------------------> >------------------------------------------------------------------------------------------------------------------------------| | | | To: [log in to unmask] | | cc: | | Subject: a problem on GC-C-IRMS hydrogen reactor | >------------------------------------------------------------------------------------------------------------------------------| 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