Dear AMMRL,
I have failed at getting any signal using Varian's gnoesy pulse sequence
(set up via gnoesy macro from a 1D proton experiment).
My sample is 10% strychnine in cdcl3. Thinking (eventually, when all else failed)
that I might have a problem with the PFG hardware I tried a second instrument --
where PFG is used more routinely, but with the same result.
I used the recommended gradient levels and gradient times for organic samples.
with ni=1 the signal is verrrry weak, since I was expecting something not too
far off what I would see in a simple H spectrum (phase reversed by 180).
mix by default is .15. If I set this just .001 sec longer than gt2 and ni=1
I got a much larger signal, though still not approaching the 1D proton.
Initially, I was confident this would work and had set up an experiment with
nt=4 and ni=128 but saw no signal, not even a diagonal.
My object was to be able to run a noesy quicker, than with the non-GS
version. Usually quite a bit of sample is available -- and thought this would be
a reasonable expectation.
With thanks,
Carl
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Carl Bachmann
UT Southwestern Medical Center
Department of Biochemistry
Dallas, TX 75390
Received on Thu May 22 2003 - 16:21:04 MST