Question

What is the stationary phase of your system?

What is the mobile phase that you selected?

Why is it necessary to wait for the solvent to reach the top of the sand layer before adding the sample? Why wait for the sample to travel into the sand before adding the eluting solvent?

Answer 1

(i) Sand is the stationary phase.

(ii) The solvent system (eluent), i.e. a mixture of n-hexane and ethyl acetate is the mobile phase.

(iii) The solvent should reach the top of the sand layer before adding the sample in order to avoid the disturbance of the sample absorbed in the sand by the next addition of the eluting solvent.

The sample should travel into the sand uniformly so that the eluting solvent will not disturb the sample and will clearly separate into the individual components of the mixture. Hence, the sample can be 100% purified.