I've been trying to do hydrogen in water by equilibration on our
PrismIII with a multiprep. I am having trouble getting consistantly
good results. I have 4 questions.
1) Does anyone use the foam insulation on top of the sample holder?
I'm finding it causes needles to bend.
2) What sort of needle do others use (diameter, type of tip)? Since I
bent the needle I had been using for ages (for oxygen in water) I've had
a lot of problems with the replacement needle clogging. It is getting a
clear plastic (presumably Kel-F) in the tip of the needle.
3) What function does the Kel-F septum perform? Once the vial has been
filled there is a hole in the Kel-F sepum which allows the gas to be in
contact with the silicone septum.
4) Can you reuse the silicone rubber septa and how often? The manual
says you can reuse them a few times but I'm beginning to wonder whether
they are leaking.
Any advice or insights will be most welcome.
School of Earth and Environmental Sciences
University of Wollongong,
Wollongong, 2522, NSW
Phone 02 4221 4586 (office)
02 4226 5903 (lab)
Fax 02 4221 4250
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