Hi all,
I'm trying to run the example NOE difference experiment from the 100
and more NMR experiments (4.8) on our ARX-500. I'm using the noediff au
program and zgh1pr pulse program. I irradiate the methyl peak at 1.9
with a decoupler level of 70dB (this power level does not completely
saturate the signal) and expect to see an NOE signal from the proton at
5.5 but not at 6.0. There are a couple of issues I don't understand
with this experiment.
1.) If I only do one cycle of 8 scans, both proton signals (5.5 and 6.0)
show an NOE, however if I do 5 cycles then only the correct signal (5.5)
shows some NOE.
2.) This signal, in the 5 cycle experiment, integrates to 7% of the
methyl signal in the control spectrum. Taking into consideration the 3
to 1 proton ratio, this leads to a roughly 2% NOE. The book indicates
an NOE of about 9%
I'm using a dilute sample (don't know exact conc. but rga set the rg to
4096). I transform the control spectrum with 2hz line broadening and
use the multiefp program to transform the other spectrum. As far as I
know, I'm doing everything correctly. Any suggestions as to why I'm
seeing #1 and #2 above?
BoB
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