Paul,

      Ours inserts are from Costech and they 're also open at both ends. --
Steve

Steven Silva
U.S. Geological Survey
345 Middlefield Rd., Mailstop 434
Menlo Park, CA 94025
ph:  (650) 329-4558
fax: (650) 329-5590
email: [log in to unmask]




                      Paul Eby
                      <[log in to unmask]>           To:       [log in to unmask]
                      Sent by: Stable          cc:
                      Isotope                  Subject:  Re: EA insert tubes
                      Geochemistry
                      <[log in to unmask]
                      UVM.EDU>


                      09/25/2004 03:44
                      PM
                      Please respond to
                      Stable Isotope
                      Geochemistry






Troy,

The inserts that we've been getting are not open at the bottom. I'm
assuming that if you are putting a quartz plug in the bottom of yours that
they are open at both ends?

Paul


At 03:35 PM 9/24/2004, you wrote:

>Paul,
>If you put a small (~1/4") plug of quartz wool at the bottom of the insert
>you should be fine, along with the quartz wool at the top of the chromium
>oxide in the combustion reactor.  This is especially necessary if you are
>combusting glass fiber filters.  As long as you change the insert before
>too much ash builds up, the insert should come out easily.
>Troy
>
>Troy E. Gunderson
>University of Southern California
>Wrigley Institute for Environmental Studies
>3616 Trousdale Pkwy., AHF 108
>Los Angeles, CA  90089-0371
>
>[log in to unmask]
>Office:  (213) 821-1431
>Lab:     (213) 740-5782
>FAX:    (213) 740-6720
>www.usc.edu/dept/LAS/biosci/tricho/index.html
>
>
>----- Original Message -----
>From: Paul Eby <[log in to unmask]>
>Date: Saturday, September 25, 2004 3:22 pm
>Subject: [ISOGEOCHEM] EA insert tubes
>
> > On our Fisons 1500 EA, we generally use insert tubes to collect sample
ash.
> > Lately though, I've been having trouble with them breaking when I try
to
> > replace them.
> >
> > They don't slide right out - they are at first stuck at the bottom, and
> > when I try to wiggle it loose, it breaks near the bottom leaving a
large
> > chunk inside. That means replacing the entire combustion tube. I'm not
> > running anything unusual in terms of samples, N and C in tin capsules,
> > sediments and freeze dried marine tissue.
> >
> > The inserts have the slits cut into them, so I suspect that sample
residue
> > is seeping through and fusing with the quartz outer tube. Has anyone
else
> > experienced this, and perhaps have a trick or two? Do others put a
small
> > plug of quartz wool on top of the chromium oxide?
> >
> > Paul Eby
> > University of Victoria
> >