[dexangeles]

im trying to do a microscale column chromatography on tomato paste separating lycopene from beta-carotene
alumina adsorbent
but using hexane as an eluting solvent, there is only 1.5 cm of separation so far between an orange-reddish (lycopene) and yellow band (beta-carotene)

what is a better eluting solvent?

1. ive been told 10% acetone in ligroin --- but i wasnt told what comes out first
2. petroleum ether --- same, i wasn't told which one comes first

[movies]

Hexane, petroleum ether, and ligroin behave essentially the same in column chromatography.  Pet. ether and ligroin are mixtures of hydrocarbons and are defined by boiling range.

Adding a more polar eluent might help.  Something like acetone, ethyl ether, or ethyl acetate are the most common choices.  It's not always obvious what compound will elute faster though.  Generally, switching solvent systems won't affect the order that compounds will elute.  If you can identify them by their color (which apparently you can) then you can tell which one elutes first, too.

[Mitch]

Yeah, I don't think your eluent is polar enough. You should try to take a TLC and see which solvent system will get you a retention time of 0.3