SecretSquirrel - 20-3-2007 at 10:51
I'd be very grateful if somebody could tell me the retention factors for these three compounds: paracetamol, propiphenazone, caffeine. I searched
Merck index and some web pages, but I can't seem to find these information. I unfortunately don't have access to any other literature.
Thanks in advance.
matei - 20-3-2007 at 11:07
I assume you mean chromatographic retention factors. Before trying to find those in the literature you might find quite useful to read some basic
facts on chromatography in general (try wikipedia).
The retention factor does not depend only on the particular chromatographic method you are using (e.g. HPLC, GC, TLC etc.) but also on the stationary
phase and mobile phase. Retention factors are only valid for a specific method-stationary phase-mobile phase combination.
Nicodem - 20-3-2007 at 11:59
There is only one useful source of such information. You need to perform the chromatography on each of the three compounds on the system you intend to
use.
SecretSquirrel - 21-3-2007 at 00:16
Thank you Matei and Nicodem. I didn't know the result depends on the selection of stationary and mobile phases. I already performed TLC on a sample
and have even calculated the retention factors so I just wanted to make sure if I got correct results for these compounds.
[Edited on 21-3-2007 by SecretSquirrel]
matei - 21-3-2007 at 10:05
SecretSquirrel,
Usually these retention factors are not reproducible so they are rarely reported in the literature. If you want to correctly identify these substances
you should try a specific reagent for each one and dip the TLC plate in it - the spot corresponding to that substance will become coloured.