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Hi Eva,

Another thing to check is to make sure the intake capillary is in the right position. The test for dilution is to weigh out 0.1 mg of a standard and run all of the possible dilutions. Then you can see which valve configuration fails. We also had a cracked capillary right at one of the fittings that was very difficult to diagnose.

Marilyn


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Dr. Marilyn L. Fogel, 
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University of California Riverside
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From: Stable Isotope Geochemistry <[log in to unmask]> on behalf of Jack Hutchings <[log in to unmask]>
Reply-To: Stable Isotope Geochemistry <[log in to unmask]>
Date: Sunday, September 15, 2019 at 8:13 AM
To: <[log in to unmask]>
Subject: Re: [ISOGEOCHEM] CO2 dilution too strong

Hi Eva,

Is it possible that the He regulator pressure was inadvertently changed on either the tank or the Conflo? I'd imagine that if either were too high you would have excess He flow for dilutions... although that should also impact your ref gas dilutions, too.

Good luck!
Jack


On Sun, Sep 15, 2019, 4:11 AM Eva StŘeken <[log in to unmask]> wrote:
Hi Dana,

Thanks for your reply! The capillaries in the Conflo are moving as they should be and look to be in the right position. We now also have encountered the same dilution issue with N2 and SO2. As soon as we dial the dilution up to 80% for any of the gases, the peaks disappear. We suspect that one of the He valves in in the Conflo may be malfunctioning, but it's not obvious. If anyone has seen this problem before, please let me know.

Thanks!
Eva