Zitat von Vernon M Russell <vrussell_at_wlgore.com>:
> I've starting running DOSY experiments to look at changes in liquid
> diffusion constants in restricted environments. The manuals recommend
> caution when using a 5mm BBFO probe with z gradient in terms of limited
> gradient strength available, recommend using restricted volume tubes or
> limiting sample volume to a cm or two and center over coil region, etc.
> Does anyone have advice on this setup? Should I use a very small sample
> height? How can one tell if the experimental setup isn't giving valid
> data?
Yes. Most important issue to overcome is convection within the tube.
This kills all diffusion experiments.
Please: use high temperature gas flow, small samples (in height as
well in diameters):
In normal liqiuds the 60 G/cm of hires probes are sufficient. Longest
gradient time is about 3 ms (try!). Play ith BIG DELTA (diffusion tine)-
In highly viscous smaples this gradiewnt strength maybe to less.
Cheers
Matthias Findeisen
Univ Leipzig
Received on Thu Jun 15 2017 - 11:25:28 MST