Thin layer chromatography

[ovidius]

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]

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]

Like what solvent to use for extraction of the compound?

[Nick]

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]

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

[Nick]

yea thats easier :wink:

[ovidius]

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]

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