Chromatography Forum

Hi, I'm a Medical Laboratory Technologist in a Nuclear Medicine Department and this is the first time for me in this forum.
I'm writing a paper on the testing of radiochemical purity of 99mTc-radiopharmaceuticals. The tests are preformed as TLC and I have some rather simple questions (or are they..?) about that:

- Is the strip always supposed to dry after the solvent has reached the solvent front and why? - and does anyone have any references on that?

- Is there any definition to what a good chromatography is/looks like?

There is a Swiss organization which has extensive quality control examples and discussion on the net, sorry I don´t have the address here. Anyway, not all proposed tests are really doing the job, I had to "reinvent" some methods.
It is mandatory that the strip is dried as fast as possible as any diffusion after stopping the elution confuses things. For instance, with the fast eluting silanized glass fiber strips it is impossible to prevent a substance from diffusing byond the solvent front before the strip is dry, that is, before measuring.
A good chromatography is one that does the job, here, and that is just were some suggested methods fail. The "bible" of TLC, namely Stahl´s book is very good for a background.
How are you detecting your TLC results?
I am wondering what sort of paper you are writing up without apparently having much background in TLC?

Hi
Not familar with your application of TLC but, in addition to Muellers answer, I would also add in general that the drying of the stripe/plate in addition facilitates detection. Residual mobile phase may interfer with for example UV detection or the reaction of spray reagents for detection, which is one additional reason why one typically add a standard/reference to each plate/stripe.

The Swiss company HW mentioned is the company Camag. Go on www.camag.com and you will have access to a lot of applications and papers. And keep your hair dryer ready!

Wheras Camag has splendid refs it does not suggest quality control methods for nuclear medicine. I was mentioning an organization of some kind of radiochemistry or nuclear medicine people.

http://www.bing.com/

yielded a simple summary of some methods:

http://www.elimpex.com/new/products/nuc ... hroma.html


next time I go to the lab I will look up what I used, if I think of it and if it is still needed.

Not going to the lab until next week I surfed a bit more and think that I found what was mentioned, it is now arranged differently, though:

http://www.sgrrc.ch/

This is somewhat frustrating, the link I gave goes only to the home page to get to the TLC examples klick on

Qualität>>Radiopharmaka>>in the last sentence of this page klick on IRA