Hello fieldworkers,
A melted-off NMR-sample tube queuing in the samplechanger carousel
can develop pressure and unexpectedly act as a time bomb, thus
becoming dangerous for people in the area nearby, particular in open
access work routine.
Burst of sealed tubes is possible from several reasons:
* chemical processes inside the sealed tube with development of gas,
* warming up a tube, which was sealed inappropriate at low temp
without sufficient evacuation,
* strained glass from the sealing process.
For prevention of accidents (and by the way saving the money for a
new probehead) we recommend our safety precaution:
Freshly sealed tubes have to be tested after reaching room
temperature either by immersing into warm water for 30 min or by
holding for 1 hour at RT in the lab before bringing it to the NMR department.
Additional security we provide by a shield around the carousel built
by our institute's workshop
(made from VA-tubing and VA-rod as well as sheets of PETG and PC).
If you want to view one of theese shields, visit my homepage:
http://schwalbe.org.chemie.uni-frankfurt.de/~zim/Samplechanger/
Take care,
JGZim
Dr. Johannes Gottfried Zimmermann
Goethe-Universitaet Frankfurt
Institut f. Organ. Chemie und Chem. Biologie
Raum N160-15
Max-von-Laue-Strasse 7
D-60438 Frankfurt
Tel: +49 69 798 29122 oder +49 179 2859 067
Fax: +49 69 798 29515
Received on Fri Sep 28 2007 - 10:38:55 MST