Hi all,
Sorry this is an old topic that people have discussed a lot before. The
glass insert in the Bruker QNP probe (ARX250) in our lab break frequently.
We have asked users to buy good tubes, we check magnet level routinely, we
put up big red-letter CAUTION sign to ask users to turn on air before
inserting sample and turn off spin before ejecting sample, we took off the
springs in the depth gauge so that it wont slide from the 1.8 cm position
... , and it still breaks! We have never had a broken insert on our other
Bruker instruments which do not have QNP probe. I'm beginning to think
it's due to the QNP switching that may cause shocks to the insert and
therefore break it. The NMR is used routinely for 31P and 19F, so the QNP
switch is used a lot. Spraying a little WD-40 once every few years can
help it to be less noisy.
It seems the only thing left to do is to stock up the glass inserts. The
cost is $80 when we bought from Bruker two years ago. I remember seeing
other vendors' price being less but can't find it. Could any of you please
remind me about the names of these vendors?
Thanks for all your help.
Wei
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Wei Wycoff
Department of Chemistry
601 S. College Ave.
University of Missouri-Columbia
Columbia, MO 65211
USA
voice: (573) 882-3291
fax: (573) 882-2754
email: WycoffW@missouri.edu
http://chem.chem.missouri.edu/nmr/nmr.html
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