Hi All,
In our chemistry department we have a JEOL ESC-400 NMR with a problem which we can't seem to solve. We are unable to lock on CDCl3. All other deuterated solvents that we normally use will lock and shim with no difficulty, but with CDCl3 the error message "autolock detects no signal" appears. Using the sawtooth pattern I can see the deuterium signal but it doesn't appear that the auto lock and gradient shim program can.
I sent our Lock/Shim unit to JEOL in Peabody, Mass. and they were able to make it work on their instrument, however, after it was reinstalled back in our instrument the problem still existed. I know that our shim files are good and we get excellent spectra when we use DMSO-d6, acetone-d6 and D2O. When it comes to student's samples, we run most of them in CDCl3.
After having a WebEx meeting with one of their engineers he confirmed that our shim files were not the problem.
I was wondering if this is a probe issue. Recently it has become harder to tune our probe to 1H and especially to the low frequency nuclei such as 31P and 11B. The folks at JEOL believe that my next move is to send the probe to them for inspection. When that happens we are usually out of commission for a month so I just thought that maybe someone has seen this sort of thing before and could give me some suggestions on how to fix this problem.
Has anyone out there had a similar problem and were able to correct it?
Any input would be most appreciated.
Thank you,
Dan Durant
NMR Manager
Mount Allison University
Dan Durant
Department of Chemistry and Biochemistry
Mount Allison University
Sackville, NB
E4L 1G8
(506)-364-2205
Received on Tue Apr 24 2018 - 08:42:23 MST