Question

In a chemistry experiment in which you extract and isolate caffeine from tea leaves...what is the mobile and stationary phase?

Answer 1

First of all ,it is not mentioned the relation between extraction of caffiene vs mobile phase and stationary phase.For your convenience,extraction of caffiene from tea leaves is done involving addition of hot water to tea leaves as caffiene is soluble in Hot water not in cold water.Further addition of cholroform(CHCl₃) to aqeous fraction is done to isolate caffiene from aqeous layer which is concentrated to get solid caffiene whose presence can be detected using thin layer chromatography. The stationary phase in TLC (thin layer chromatography) meant for caffeine identification is silica gel and the solvent system used is hexane ethyl acetate mixture (7:3). which acts as the mobile phase.