Stable Isotope Geochemistry


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German Mora <[log in to unmask]>
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Stable Isotope Geochemistry <[log in to unmask]>
Wed, 11 Feb 2004 17:16:31 -0600
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We have a problem with our Conflo-III system, which is attached to a
Delta Plus XL. When we turn on any of the reference gases (CO2 or N2),
we get a large signal (>14 volts).  My first thought was that the
pressure was too high. We decreased the pressure using the gauge in the
Conflo unit, but there was no luck. We checked the pistons and the
distances of the capillaries inside the open split glass cell when they
are on and off, and all of them looked ok.  I also thought that we were
not getting any or low flow of helium. We measured the flow of the
helium stream entering the open split glass cell and it was what is
expected (~2 ml/min).  We even disconnected the EA to see if somehow the
problem was with the EA, but we still see the same problem.  What makes
this problem so particular is that when we turn on the CO2 reference gas
we only get a large signal on mass 44. Masses 28, 40, or 18 only show a
slight increase. When we turn on the N2 reference gas we only get a
large signal (>14 volts) on mass 28, not on any other mass.  I ran out
of ideas, so I would  really appreciate any help.



Germán Mora
Assistant Professor
Depart. of Geol. & Atmosph. Sci.
Iowa State University
Ames, IA 50011-3212

Phone: 515-294-7586
Fax:   515-294-6049
E-mail: [log in to unmask]