If you don't want to run column for separating terpenes and sesquiterpenes then concentrate your methanol extract about 5-10 times and add hexane to it for extraction. you need to add excess hexane because hexane is partially miscible with methanol.
so add enough hexane to your extract till you could see two separate layers.
These are generally non-polar, and often volatile. If you use silica gel column chromatography with a hexane/ethyl acetate gradient, they'll generally be found in the non-polar fractions containing mostly hexanes. If using reverse phase (C18, for example), they'll generally elute late. If using silica based C18, you may need to use non-aqueous reverse phase to elute them.
I agree with Jack Silver. Another old approach to partitionate a total extract consist in suspending the dried extract in water, the resulting suspension is then extracted with a series of solvents of increasing polarity (e.g. hexane, chloroform, ethyl acetate, butanol,and so on, you may choose your serie of solvents or also refer to several existing eluting series available in literature) so as to distribute the components of the mixture depending on the their polarity.
In any case the best solution for the study of most of the mono-and sesquiterpenes is the hydrodistillation followed by analysis by GC-MS.
thanks sir, I have to ask one more question for performing coloum chromatography how will we select the mobile phase so that I can isolate the compounds properly
Hello. First you do a raw column with Hexane/Ethyl Acetate in increasing polarity (100:0; 90:10; 80:20; and so on) from the methanolic extract. You will get 10 crude fractions from these big column. Then, specifically for each of your crude fractions, then you optimize the mobile phase (Hex, EtAc, Acet, MeOH) to separate the maximum possible. You can also use polyamides to get rid of the chlorophylls.
thanks Ricardo Sir, Sir can I use Chloroform/methanol in increasing polarity
You can do that, but is better to start with less polar solvents. In general, I use chloroform/methanol 1% or 2% to further purify the compounds in a later stage. If you apply that mobile phase too early, you may not be able so separate with success all the compounds.
To add to Ricardo's answer, you can substitute petroleum ether for hexane and acetone for ethyl acetate if you don't have hexane or ethyl acetate. Chloroform is fairly polar compared to hexane, and a hexane/ethyl acetate gradient will probably resolve the compounds better.
If you don't want to run column for separating terpenes and sesquiterpenes then concentrate your methanol extract about 5-10 times and add hexane to it for extraction. you need to add excess hexane because hexane is partially miscible with methanol.
so add enough hexane to your extract till you could see two separate layers.
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