Question

7. How does TLC complement column chromatography? Explain your answer with an example (2 points).

Answer 1

TLC helps in identifying the suitable solvent which needs to be used during column chromatography.

correct solvent choice is very important in column chromatography, otherwise if we use some undesired solvent whole compound will come down altogether and we will get a mixture of products. Thus, identification of correct solvent to use is precondition to get a good separation using column chromatography.

Eg : if we have ferrocene and diacetyl ferrocene mixtute, we will first do TLC by marking a spot on the TLC plate. we will use less polar solvent like hexane. we will observe that ferrocene will go with the solvent at a faster rate while Diacetyl ferrocene will be strongly adsorbed on TLC plate. Thus, we can conclude that at the starting of column chromatography we will start with non polar solvent like hexane.