Question

With respect to liquid column chromatography in which the stationary phase is silica, propose a suitable strategy for separating two components of a binary mixture that fail to move when hexane is the mobile phase and move the same distance when methanol is the mobile phase. Explain your reasoning.

Answer 1

For separating two components of a binary mixture that fail to move when hexane is the mobile phase and move the same distance when methanol is the mobile phase, which implies the both the compounds are polar.

Hence we have to try different polarity range of mobile phase to separate the compounds.

So first try 5% (v/v) methanol in hexane. Check any compound is coming or not. If yes then continue passing same solution unless there is nothing in final round.

Then increases the polarity of the mobile phase. Say, 10% (v/v) methanol in hexane. Then follow the same procedure unless you get the two compound in two different polar mobile phase.

Both the compounds are polar. But polarity value for both the compounds are different. So, they are highly soluble in respective polar mobile phase. So by this way we can separate these two compound.