Thanks very much to everyone who replied to my previous post regarding
my attempts at decoupling 19F from 13C. I won't post a summary of
responses this time since almost all of them said basically the same
thing. Most responses indicated that a low-pass filter is necessary on the
13C channel to cut out any 19F frequencies.
Unfortunately this did not work for me. Again I did a coupled 13C
spectrum and saw the solvent peak in very few scans but in the 19F
decoupled spectrum there is only noise.
The instrument is a venerable Bruker DRX, 500 MHz (actually, my favorite
machine out of all we have here), 13C channel amp is a BLAX1000 switchable
between 300 and 1000 watts, 19F channel amp is a BLARH100, I am using a BB
preamp with a low pass filter (31P and lower) and a (from the label)
HP/19F preamp with a high-pass 13C stop filter. The probe is a TXI
1H/13C/15N probe.
I still think that we must be able to do this because with the setup
above I can observer 19F without problem. Perhaps a different probe?
Grasping at straws at this point.
Hope everyone is having a fine summer. Cheers.
Dr. Keith Brown
Department of Chemistry/
Saskatchewan Structural Sciences Center
University of Saskatchewan
Saskatoon, Saskatchewan
306-966-1725
http://chem4823.usask.ca/kbrown.html
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There are only 10 types of people, those who understand binary
... and those who don't.
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Received on Fri Aug 05 2011 - 06:41:23 MST