Dear Spinlanders,
Here is the summary wrt NMR of 3H and 14C labeled cmpds.
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Regarding 3H NMR, a good source of information is the web page
of the National Tritium Labeling Facility at the Lawrence Berkeley
Laboratory (http://www.lbl.gov/LBL-Programs/NTLF/).
This will direct you to many more recent references on 3H NMR. In
particular the following reference gives some good sample handing
info : "Applications of High Resolution 3H NMR Spectroscopy", P.G.
Williams, Fusion Technol., 14, 840-844 (1988).
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Dave Wemmer might be a good person to consult.
He gave a talk on doing 3H NMR at the ENC.
wemmer@cchem.berkeley.edu
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Phil Williams at Berkeley has a lab set up specifically for such
things. I'm sure he could give you the best up-to-date advice. His
telephone number is: (510)-486-7336. Some people from here did 3H NMR with
him and found him very easy to work with. I have no idea what it would be
like to contact him from industry but I would try it.
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thanks for the citation. It's not a bad introduction to 3H NMR, but a bit
dated now, as far as the instrumentation goes anyway. I've no info on
USA-specific licensing requirements, try Phil Williams at the National
Tritium Labelling Facility at Berkeley, he usually reads the BUM mail
anyway. PGWilliams@lbl.gov http://www.lbl.gov/NTLF/PGW.html
Look in "Journal of Labelled Compounds and Radiopharmaceuticals" for
general background.
As far as the spectroscopy is concerned, the proton spectra of tritiated
compounds shouldn't be affected at all, by the presence of tritium, at the
sort of isotopic abundance that you will probably be dealing with, just as
we don't usually notice the presence of natural-abundance deuterium, and a
sealed sample will present no "external" radiation hazard. These days we
are using Wilmad ptfe/fep tube-liners, inside Screw-cap Do check the legal
requirements carefully though, they tend to be complicated and inconsistent.
I have run spectra of C-14 labelled material, from time to time and don't
remember any particular problems. We have Departmental and University
Radiation Safety Officers to sort out the (UK) safety and legal
requirements, I just work within the framework they give me.
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I wrote a communication in Rev. Sci. Instruments and presented a 3H
spectrum as an illustration of a bb technique I thought I had invented. I
think it was 1973. Look up lewis w cary and you should find it. I hope
this helps.
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I can't speak to 14C issues since I've never handled the stuff (gamma
versus beta, etc.) but I have done 3H NMR about ten years ago while at
Parke-Davis Research. As you know, 3H is a beta emitter and as such the
"hottness" is contained within the walls of the NMR tube. The real danger
would be if the sample spilled and you injested it or breathed an aerosol.
Our radioisotope people would isolate the material, put it in the NMR tube,
check for external contamination and then deliver the tube to me in an
appropriate safety container. I ran the samples and returned to them.
Basically, this meant using gloves and GLP. As for the spectrometer
itself, we put a plastic container under the probe to collect spills from
breakage (never happened!) and turned off air to probe and magnet after
lowering the sample to reduce the possiblity of aerosol in case of breakage
(never happened!). Typically, the samples sat in the probe for hours since
the actual molar quantity of tritium was quite low. All in all it was
quite easy to do and since we were careful and prepared, Murphy never
showed up. (And, I kinda like the third eye that's grown in the back of my
head since I've got kids now!)
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I have done some 3H NMR. I think the standard precautions are teflon tube
inserts and possibly probes which will not leak out of the bottom
(although we have none of those). The teflon inserts do limit your ability
to shim, so I try not to use them. We did have to get a permit from our
department of radiation safety, but I don't know what the actual
requirements are.
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I know we have had 3H labeled samples run on our instruments by students in
the John Katzenellenbogen group here at Illinois. His contact info is:
name: katzenellenbogen john a
email: katzenel@aries.scs.uiuc.edu
phone: (217) 333-6310
address: 461 ral box 37, mc 712
: 600 s mathews
: urbana, il 61801
I don't remember the concentrations they were working with. The students
always told me (at least I like to think they did) when they were running
3H labeled samples, and I said the only thing they had to realize is that
if the sample broke, they might be paying for a probe.
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Dave Wemmer's group at Berkeley does this. A nice talk was given at the
ENC (Tues. 10 AM). The abstract can be found at www.enc-conference.org.
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Thanks to all for sharing your experiences and citations.
Best regards,
Lawrence
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