[Ifeffit] Pellet sample preparation

[Welter, Edmund]

Hi Dominik,

you can use cellulose powder (Aldrich) it forms very stable pellets and 
does not stick to your pressing tool like BN. Chemically it is 
definitely less inert than PE but I never saw that it reacted with 
samples. An advantage of the cellulose powder over the Uvasol PE is that 
the grain size distribution is much more homogeneous and the particles 
are smaller enabling much more homogeneous samples than the PE (That is 
you must not sieve it before use). If you use BN be sure to have some 
vaseline at hand, otherwise you will not be able to remove the pellet 
from the pressing tool. Some people used PTFE powder, don't know if it 
works but at least F is a heavy element compared to H. When Merck ceased 
to sell the Uvasol PE we tested a all PE powders we could lay our hands 
on but couldn't find one that formed stable pellets.

Regards,
Edmund

Dominik Samuelis wrote:
> Dear list,
> 
> for many years, I have used  "Merck Uvasol Polyethylene for  
> spectroscopy" PE powder as a diluent and binder for pressing  
> self-supporting pellets especially of air-sensitive substances. When I  
> today wanted to order a new bottle, I had to learn that it's not  
> available anymore (actually, since 2002... :-)).
> 
> Does anyone of you know about any other supplier of spectroscopy-grade  
> polyethylene powder? And more general, which binder/diluent do you use  
> for preparing pellets of sensitive substances ?
> 
> Best regards,
> Dominik
> 
>