UW CHEMISTRY NMR

Dear Users

Thank you for those of you who brought the following intermittent issue to my attention :

Locking fails sporadically, but mostly on solvents with a weak lock signal, such as CDCl3.  The autolock failure has been observed, sometimes after Topshim completes and at other times, even during initial locking attempts.

The good news is that, the subtle issues underlying this behavior have been identified and remedied. Part of the solution was to optimize the Locking related parameters for respective solvents.  So far, these parameters have been generic values that are supposed to be sufficient for most of the solvents, i.e. factory set values.   But, for some solvents like CDCl3, these were borderline acceptable values and that led to this unexplained failure for some sample tubes and not the others, even though you used the same solvent in both cases.

I am confident that it should be smooth sailing from now on as far as Auto Locking goes.  Please do post a log message, if you observe anything to the contrary.

NMR Facility Manager

10/19/2022