Depends on the detector, but even if you could detect them, volatile terpenes won't be easy to recover from fractions, usually mixtures of water, MeCN, MeOH, etc.
If your product is a volatile terpene it may evaporate even bofore water or it could coevaporate with it or with the other solvents. Considering the dillution of fractions collected with semi-preparative methods, distillation might be troublesome too.
If your compounds are too volatile to rotaevaporate from water, MeOH, MeCN, etc. then I would go for "normal" phase semipreparative columns, insted of standard HPLC-lilke reverse phase columns. That would give you fractions with easier to evaporate solvents; the same you could use for silica gel columns.
Of course all this means that you wouldn't be using the same column. In the end it all depends on the boiling point of your terpenes.
Thank you Xavier, my compounds are not too much volatile its molecular weights are 264,290,234 and 324 it is easly soluble in ethyl acetate and methanol, Insoluble in water ,It was collected from repeated column chromatography with Hexane and Ethyl acetate Now i am using preparative HPLC for the final purification with C18 column under UV detector, Can u suggest any method available for the seperation ?
Found solution? Preparative PLC doesn't necessarily mean reverse phase so organic solvents (hexane-IPA) can be used and then removed by fraction distillation instead of rotavaporate them.
More tricky is the fact that terpens might not be detectable in UV detector, it would help a diode array detector maybe