Definitely purely academic:
I recently saw an article on NMR of 99Tc which is spin 9/2. For this nucleus, there exists an excited state which is called 99mTc. This state decays by gamma-emission with a half-life time of 6h to 99Tc (used in medical imaging).
In our NMR group this triggered a discussion whether an "excited nuclear state" has a different spin-state or gyromagnetic ratio compared to a "nuclear ground" state? Any ideas around in this community?
Thanks and Cheers.
Tc99m has, to my knowledge, a nuclear spin of -1/2. Thus I would expect a difference in magnetogyric ratio and chemical shift range as well, but I think this has not been measured yet.
Agree w Christian. Spin - 1/2. It is probably difficult to do NMR on 99Tcm for two reasons. A). The amount of material made for radio tracers is probably very small, possibly nanomols or less, so sensitivity would be an issue. B) consider the special facilities needed to handle the material! There used to be a tritium NMR facility at Berkeley...
James is right in what he is saying. 0.2 µg (!) of 99mTc has an activity of roughly 10 GBq, so, if you want to have half a mg in your NMR tube the activity will be aroung 25 TBq, which would need to be handeled in a lead-shielded hot cell (if this can be handeled at all). Since the concentrations that can be obtained e.g. by radionuclide generators are so small, I seriously doubt you can gat enough material (and that in short time) in one place to do the NMR measurements.And yes, you will need to work in a controlled area for that research.Although I have to point out that there are a few NMR spectrometers in radioactive controlled areas in the US (e.g. LNNL) and in Europe (KIT-INE, ITU) as well.
I would add that there also a lab in France (CEA) where tritrium NMR experiments are performed.
Yes, Gaspard is right there. France also has an NMR spectrometer dedicated to actinde research (at CEA Marcoule).
Dear colleagues,
thanks for all your comments - now we know! It actually was never planned to use it for experiments. We were only wondering to what extent the excitation of a nucleus may affect the magnetic moment. Obviously there is quite a influence.
In our company we also have a Tritium probehead for synthesis control of tritiated compounds used for metabolic studies....radiactivity is an issued but it can be handeled!
Thanks again
Alfred
- Badges
- Science topic