Question

For the isolation of lycopene from tomato paste, lycopene and carotene were separated by column chromatography followed by thin layer chromatography, the spot for beta carotene was not seen. Why?

Answer 1

Beta- carotene is the yellow pigment of carrot,which is an isomer of lycopene.

here, the double bond changes to form ring structure and this is also a constituent of tomato. beta carotene is less polar compare to lycopene.
when column chromatography is perfomed, being less polar it doesn't stick to the column and travel faster compare to lycopene.
in column chromatography, different samples are collected at different test tubes from the top of the column, so while collecting the sample, the beta-carotene will be collected first in a separated test tube and sample containing lycopene in another. the later one will taken for thin layer chromatography, where diiferent spot will be formed but,for beta carotene no spot will be formed, because of the absence of it,