We have a Bruker 1.7mm cryoprobe that most of the time works great, however, fairly regularly we cannot find a lock signal. It seems to be related to the NMR tube because other samples with the same solvent produce a lock signal and transferring the sample to a different tube often produces a lock signal. 1.7mm tubes use a special spinner turbine that lets the tubes hang from their caps rather than gripping the glass tube. I suspect that when placed in the magnet, slight misalignment of the cap on the tube mis-orients the tube, prevents it from falling into the opening in the top of the probe and the tube is instead pushed up out of the spinner. Unfortunately, Bruker is the only source of 1.7mm NMR tubes that I have been able to find. Does anyone know of another source, and has anyone else seen this lock problem?
Brendan M. Duggan, PhD
NMR Facility Director and Associate Project Scientist
Skaggs School of Pharmacy and Pharmaceutical Sciences
University of California at San Diego
9500 Gilman Drive, MC 0684
La Jolla CA 92093
office phone: (858) 534-8763
lab phone: (858) 822-7826
cell phone: (858) 692-2298
email: bmduggan_at_ucsd.edu
http://sopnmr.ucsd.edu
Received on Wed Dec 10 2014 - 12:18:37 MST