Question

Darcy got a nice seperation for his 3 component mixture on a tlc plate that was developed in pentane:ethyl acetate (5:1v/v). Unfortunately, his column seperation was woefully unsuccessful.. everything quickly came pouring off the column together. Heres what he did: He made a slurry of silica gel with ethyl acetate to prepare his column, being careful to tap it during loading in order to remove air and compact gel. Once ready, he put a bit of sand on top. Loaded 1 gram of product that he had dissolved in 1 mL of ethyl acetate. he then began to elute with 5:1 pentane/ ethyl acetate solvent combo and collected 8 fractions. What mistake did he make? what should he have done instead?

Answer 1

Solution :-

The solvent used for the dissolution of the mixture was the ethyl acetate

And she again used ethyl acetate to eluste the mixture from the colum

since the mixture is soluble in the ethyl acetate therefore at the time of the separation all the mixture again get dissolved in the ethyl acetate and nothing remain in the pentane therefore all came out together.

Therefore to correct the error Darcy need to use the different eluate combination to separate the componetns from the mixture.