Dear Ammrlists
I'm in one of those mind raveling situations trying to run
something very simple which does not appear to work at all,
even after multiply rechecking EVERYTHING.
Particularly I am trying to get Expt 9.4 "29Si NMR
Spectroscopy with DEPT" in Berger's '150 & More..' to run, in order
to decrease spectrometer time and get rid of the glass signal.
This expt also appears in the earlier version of the book
so surely it is right as writ...but maybe not.
In my hands doing straight decoupled 29Si on my TMS sample I
get s/n 900 in a single scan. With the Berger DEPT sequence
I get only 250 after jiggering the final delay.
I have quadruply checked my pulse calibrations for 29Si and 1H,
being sure my '90s' are not 270s, that I have not reversed powers
or labels for the two nuclei/pulses, that my constants and
multipliers are right (his example is TMS!) that I have his
pulse sequence correctly translated, correct phase cycles,
etc., etc. etc!!!
I was puzzled at the discussion in the Comments for Expt 9.4
on the length of the final delay ...for INEPT which this is not.
When I do vary that delay at least I get some Si signal but
nothing like the predicted enhancement.
I am hoping some lab is out there which does a lot of routine
29Si can straighten me out on applying DEPT to 29Si. I am
running xwinnmr 2.5 on an AVANCE600.
Thanks in advance
Charlie Dickinson
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+ Charlie Dickinson, PhD -
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Received on Mon Jul 07 2003 - 09:36:52 MST