Hi Beth
I would support Feng's suggestion with checking the 2H tuning. Easiest way
is: rpar gradshim1d2h, wobb.
Unfortunately adjusting the 2H tuning is not that easy.
You can add an option to topshim to increase the scans. Add the option
"durmax=xx" typically a value of 60 will improve matters.
If that helps you need to change the shim command in ICONNMR to
"topshim durmax=60"
Shimming will take a bit longer but it is more likely to succeed.
Best regards
Clemens
On 1/17/2025 1:16 PM, Beth Moscato via groups.io wrote:
Hi everyone-
We have an AVANCE III (TS 3.7pl5) that’s been sporadically failing
samples saying that the signal to noise is too low. Most of the samples seem
to be marginal quality – usually CDCl3, sometimes with precipitate
or water droplets – but they often manage to successfully shim on
our AV III HD spectrometer, and I’ve noticed a dramatic uptick in
the number of failures recently.
Note that most samples, including most samples in CDCl3, have successfully =
run in TS. The TS data I’ve seen from the failed samples show a similar
pattern to those from normal samples (suggesting that the difference is
quantitative and not qualitative).
I’ve done a 3D shim recently, but it hasn’t helped. The lock
phase is set appropriately.
Is there a way to increase the number of scans acquired in TS for specific
solvents? I’m not thrilled with it as a work around, but if it stops
failing the samples, that would be an improvement over the current situation.
Thank you!
Beth Moscato
Temple University
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Received on Sat Jan 18 2025 - 05:39:06 MST