RE: Locking on the standard

Zennie, Thomas (Thomas.Zennie@wl.com)
Mon, 11 May 1998 17:23:09 -0400

We use the 0.1% ethylbenzene in CDCl3 standard to lock and shim between
users on our open access NMR's. I have a macro that adjusts the lock
level, and gain level and Z0 optimum for CDCl3 and then runs autolock
and autoshim. Each users when they are done with their samples, puts the
lock standard in the magnet and runs the macro and leaves. We have many
different samples in many differents solvents being used all day. A D2O
sample may be followed by a CDCl3 containing sample. The chemists can
have a problem trying to lock and shim using the weaker CDCl3 lock
solvent with some pretty dramatically changed shims values used for
reactions mixtures in DMSO and D2O!. The shim values have stayed pretty
stable with very little adjustment on Z3 and Z4 to make s/n and line
shape for our monthly SOP calibration. It has worked VERY well for us.

***************************************
Dr Thomas M. Zennie
Parke-Davis Pharmaceuticals
Analytical Development
188 Howard Ave
Holland, Michigan 49424
email: thomas.zennie@wl.com
phone 616-392-2375 ext 2423
fax 616-392-8916

> -----Original Message-----
> From: Charles L. Anderson [SMTP:shiulong@bayou.uh.edu]
> Sent: Monday, May 11, 1998 12:22 PM
> To: ammrl@wwitch.unl.edu
> Subject: Locking on the standard
>
> I have always be taught that it is common courtesy to lock and shim on
> a
> standard before you leave an NMR. This way the person coming after
> you
> knows what to expect when they set down at the spectrometer. However,
> I am
> getting the feeling that not all NMR facilities do this. Before I
> arrived
> here they did not lock and shim on a standard so there has been some
> resistance to this. I would be interested in hearing some input on
> this
> subject. What do you do in your facilities?
>
>
>
>
>
>
> Charles L. Anderson, Ph.D.
> Manager NMR Facilities
> Department of Chemistry
> University of Houston
> Houston, TX 77204-5641
> Office: (713)-743-2728
> Fax: (713)-743-2709
>
> "Anything one man can imagine
> others can make true"
> Jules Verne