Hi folks,
For unknown samples we would often like to make use of INADEQUATE,
But it's pretty rare that we have enough material to make this completely
trivial.
We have considered 1,1-ADEQUATE, but we have only carbon optimised cryoprobes
and my experience is that on these particularly you don't get anywhere near
as much gain as you might think from proton detection (obviously the situation
is completely reversed on 1.7mm cryoprobes, but we don't have access to one).
We also often need correlations between pairs of quaternaries which you don't
see there.
In my general experience, the standard Bruker inadphsp, which uses a phase cycle
designed for suppression of rapid pulsing artefacts, gives good results with
minimal artefacts. However, in principle single-transition variants
(INADEQUATE-CR, LASSY) should give a measureable S:N improvement (in theory
factor 2), so this would seem to be worth pursuing since we get more and more
cases where this might be a useful experiment.
Does anyone have a pulse sequence for either INADEQUATE-CR, LASSY, or any other
preferred variant for Bruker systems, and / or any comments on whether the gains
are really worth it? And for the rare cases where we really have a lot of sample,
any views on the best fast implementations?
Will summarise comments, and if no one has a sequence I might cobble something together....
Kind regards
Pete
--
Peter Gierth
Senior NMR Specialist
Yusuf Hamied Department of Chemistry
University of Cambridge
https://www.ch.cam.ac.uk/analytical/nmr
Received on Mon Nov 21 2022 - 19:02:44 MST