Just last week we ran a single sample that was a positive control for
someones d15N tracer experiment. The material was already packed into a
tin. After this sample, three in house standards were dropped, the insert
was changed, and another ten in house standards and then our d15N of in
house standards was normal.
Earth and Space Sciences
University of Washington
Seattle, WA 98195
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On Wed, 25 May 2011, Chang, Alice wrote:
> Hi all,
> Has anyone run really enriched (d15N = ~1000 per mil) samples through their EA-IRMS system? In a
> previous thread (Nov 2009) I had asked about how to clean surfaces after using enriched tracers,
> and someone suggested that I not run anything >500 per mil. My student with the 1000 per mil
> samples would like some quick results instead of sending the samples elsewhere, and I am just
> wondering if it's worth running these samples on my sole EA that is used for both natural
> abundance and less-enriched samples.
> If I were to run these highly enriched samples, what would be the proper protocol to prevent
> carryover to the next sample, and to decontaminate the EA-IRMS altogether? Run 5-10 acetanilides
> in between each sample? Run these samples near the end-of-life of the column chemicals? Run an
> autosampler tray full of acetanilides before analysing natural abundance samples again? If
> contamination arises in the connecting tubings, how best to clean those?
> If I decide not to run these samples on my EA, is there anyone out there who can?
> Thanks for your thoughts.
> Alice Chang
> Stable Isotope Facility
> Department of Forest Sciences
> University of British Columbia
> Vancouver, BC, Canada
> phone: 604-822-3047