Thin layer chromatography

ovidius · Junior Member Joined: 06 Apr 2005 Posts: 7

Hello. I need a little help. For what purpose is thin layer chromatography good? I read that its the method to separate compounds. But for what purpose? only to detect which compounds are present in a mixture or to separate this mixture like by destilation or krystalization? From what i read i got that it is only used for detection. Please dont explain me what destilation and crystalization is. I know it.
Any help would be great. Thanks

Nick · Regular Joined: 06 Apr 2005 Posts: 23 Location: Spain atm

you need it in labs, if you have e.g. mixture of organic compunds and want to look how far a reaction has gone.
or a fast and cheap method for pre analytical methods, to know what collumn you have to use for the separation of the compounds.

hope this helps

ovidius · Junior Member Joined: 06 Apr 2005 Posts: 7

Like what solvent to use for extraction of the compound?

Nick · Regular Joined: 06 Apr 2005 Posts: 23 Location: Spain atm

you use mixtures of organic solvents, --> different retention times for the different compounds on the thinlayer.
depends what you expext to find.
if you think you have polar substances in the solution , you use polar solvents. and nonpolar solvents for nonpolar substances.

i take it you know how thin layer chromatography works?

seuss · Posted: Wed Apr 06, 2005 4:56 pm Post subject:

just see this link http://orgchem.colorado.edu/hndbksupport/TLC/TLC.html Wink

Nick · Regular Joined: 06 Apr 2005 Posts: 23 Location: Spain atm

yea thats easier Wink

ovidius · Junior Member Joined: 06 Apr 2005 Posts: 7

Thanks thanks thanks. So it is used for detection how many compounds are present in a mixture and which. One last question. If i spotted the plate by three standard compounds and by one unknown compound, and unknown compound had equal colour and distance from the start with one of the three standards, does it mean that this compounds (one of the standards and unknown comp.) are identical?

Nick · Regular Joined: 06 Apr 2005 Posts: 23 Location: Spain atm

with a very high percentage yes.

if the matrix (mixture of compounds) is not too complex, the concentration of the compounds not too high (overloading the plate), its very likely.
if you are not exactly sure, a 2-D TLC is helpful. (flip the plate 90º and let it develope in an other solvent).

some compounds are colourless (UV-lamp needed)

hope thats not too confusing