We used to have the problem of having a hole on a new glassy carbon
tube. Soaking the ceramic tube in 1N HNO3 for three days solved the
Hope it helps.
On 18.03.2015 08:47, Misuk Yun wrote:
> Hi All,
> I am a beginner on TC/EA. Your advice will be very helpful!
> The story is....we have been trying to set up a method of dD
> measurement with silicate minerals (dD only, not d18O).
> I think that the method is fine...
> The problem is...when I reduced reactor temperature to change the C
> crucible, I found both ceramic tube and glassy C tube were cracked.
> This happened twice in a row. I reduced the temperatures of reactor
> slowly at the rate of 50C/20-30mins.
> The cracking was on the hot spot (both incidents).
> There was dark gray-black material built on the surface of glassy
> carbon (hot spot).
> I think this is the carbide, which other users mentioned before?
> This time, the glassy C tube (at the hot spot) got thinner and had a
> small hole.
> I do not see the expansion of ceramic tube though.
> It looks like that there was some reaction going on.
> I only ran biotite and muscovite with this packing.
> When I ran silver phosphates a few years ago, this did not happen.
> Anyone had same problem? Then, how did you solve this problem?
> One curiosity as the beginner is that I was wondering if anyone tried
> the analysis with ceramic tube only (no glassy carbon)?
> I am interested in hydrogen isotope only (not oxygen isotope).
> What if I pack the ceramic column with glassy carbon chips, and add
> nickelized carbon powder in sample Ag cups?
> Then, I have to change the bottom feeding setup to the standard setup.
> Right now, we have the bottom feeding setup.
> Thank you.