I have a mixture of 2 products and I want to know if there is a quick way (maybe with TLC?) of knowing that these two are isomers.
Depends on the type of isomer. Structural (constitutional isomers) can often be resolved, as can cis/trans isomers. Eantiomeric compounds (mirror image isomers) are resolved on chiral media, but not general TLC plates. Some diastereomers can be resolved too on TLC.
You can not isolate two enantiomers by TLC. Other isomers may be separable.
If they are structural isomers so they are different in chemical environment so you have to select specific mobile and stationary phase. Enantiomers show different behavior only in chiral environment. If you select a stationary phase of TLC as chiral it may be possible, Normally silica gel is achiral it can converted into achiral stationary phase by a reaction with a chiral molecule. For column chromatography this very popular for TLC you have to search. After this i also think is their any possibility of chiral mobile phase if not possible to find chiral SP for TLC.
Depends on the type of isomer. Structural (constitutional isomers) can often be resolved, as can cis/trans isomers. Eantiomeric compounds (mirror image isomers) are resolved on chiral media, but not general TLC plates. Some diastereomers can be resolved too on TLC.
Historically, enantiomers can't be separated by TLC.
But, I think if you make a mixture between proportions of cellulose (or one of its derivatives), chitin, or other chiral polymers with silica, and preparing the TLC plates by using these mixtures.
You might succeed to separate some enentiomers.
I didn't try it by my self, but I think it might work!!!!
Go for measurement of Optical rotation, then use HPLC to separate on basis of polarity but that need accuracy and precision. All the best
thank you all for your responses!the information has been very useful!
Welcome,
You would try this one
http://www.sigmaaldrich.com/catalog/product/aldrich/z265799?lang=pl®ion=PL
if these two molecules are diastereoisomers then it could be separated in two spots by using TLC over the use of appropriate mobile phase . if molecules are enanatiomers then it is impossible to sepaerate on TLC ,you can go for chiral HPLC.
I agree with the suggestions by Deepak, Chiral HPLC will be preferred for separation of enantiomers.
The answer by Jack Silver is appropriate as it depends upon the type of isomers you would like to separate. Kindly modify your question accordingly.
from you question I assume that you can separate them as you know you have 2 products but just want to make sure if they are isomers? If you have a LCMS available and it separates them, then isomers would have the same mass. Otherwise you need to separate by any of the suggested methods and characterise further with MS, NMR,..
It is possible through HPLC provided you have chiral columns, in which both the isomers (if present) will have different retention time.
If you can separate your isomers on TLC, then you may not need the chiral column. Even simple column should work....
plz find the link,"How can you predict relative Rf values of cis-trans isomers in thin layer chromatography?"
http://chemistry.stackexchange.com/questions/26835/how-can-you-predict-relative-rf-values-of-cis-trans-isomers-in-thin-layer-chroma
you can creat chiral derivative and get them separate on TLC as normal compound
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