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Hello Analytical Experts-

I am running a Costech Elemental Analyzer attached to a Delta V Advantage
IR-MS, and have been having issues with the combustion chamber quartz
insert fusing to the oxidation column (we have had to the replace the
oxidation column three times now because of this, and this is less than
ideal).

Our setup:
The insert has ~ 1 cm of quartz wool at the bottom with ~2-3 mm of
Chromium(III) oxide on top of that. I have been using the medium (5x9 mm)
tin capsules for loading samples (49 per run, 2 to 3 runs per insert). The
samples I have been running include volcanically-derived glacial sediments,
snow algae, and hot spring biofilms (mostly composed of amorphous silica).
Some of the samples have been acidified with HCl to remove DIC and
carbonates, but have all been rinsed with 18.2 MOhm/cm water to remove all
Cl- before drying and grinding.

It seems as though the insert quartz is fluxing and being stripped away,
enlarging the slit openings and weakening the insert, allowing the tin to
leave the side slits and fuse the insert to the inside wall of the
oxidation column. Also, there seems to be a tendency for yellow-ish
melt/precipitate to form at the bottom of the insert, fusing it to the
oxidation column there as well. I have attached an image (pdf) of the last
failure with examples of what I am trying to describe.

The temperature of the combustion chamber/oxidation chamber is at 1000 C
(checked with thermocouple). This has happened a few times in the past, but
never consistently like this.

If any of you happen to have had this problem and might know 1) what is
going on, and 2) the best way to fix the problem, I would be eternally
grateful for your time and help.

-Jeff

-- 
Jeff Havig, Ph.D.
Adjunct Faculty
Room 517
Geology-Physics Building
Department of Geology
McMicken College of Arts and Sciences
University of Cincinnati
Cincinnati, OH 45221-0013


MAD EGG LAB Website <http://www.jeffhavig.com>

https://scholar.google.com/citations?hl=en&user=wMfFwp8AAAAJ


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