Question

TLC Lab question:

Zeaxanthin is the pigment that gives paprika its characteristic color. Based upon your knowledge of the structure of b-carotene, would Zeaxanthin have a higher or lower R_f value compared to b-carotene if a mixture of Zeaxanthin and b-carotene were to be spotted on TLC plate which is then developed in a 60 % acetone in hexane solvent system? (Assume that normal phase thin-layer chromatography is being carried out).

Answer 1

If a mixture of Zeaxanthin and b-carotene were to be spotted on TLC plate which is then developed in a 60 % acetone in hexane solvent system, the Zeaxanthin spot on the TLC will be lower in comparison to the spot of b-carotene due to the polarity differences. Thus Zeaxanthin will have a lower Rf value compared to b-carotene because Zeaxanthin is a polar molecule in comparison to b-carotene. If structure observtion of the both the molecules is carried out this is evident. The b-carotene is a non polar which moves ahead and other one lags below hence the Rf values also.