We have to choose a nondestructive visualisation technique for TLC- Carla is observing that all the triterpene spots are UV insensitive. If one goes for HPLC, RI detector has to be used. On TLC, spray with distilled water- you will find opaque bands (triterpenes and other hydrophobics will give you opaque bands).

If you want to use destructive reagents, cut one edge of the TLC plate, spray and then match to cut the un-sprayed main part of the TLC plate.

I would suggest you to use a preparative GC.

I meant to say GC for analytical purposes and preparative TLC or classical or flash chromatography for purification.

I would suggest you to use a refractometer detector

Anisaldehyde sulphuric acid reagent can be used for detection in TLC. After visualistion, calculate Rf values and do a preparative TLC and scrap the required spots. If required you can cover a portion of the plate (vertically) and spray the reagent to avoid reaction to all portion of the spot.

You can refer Plant Drug Analysis by Wagner for the reagent preparation and application. See if it works...

you could try iodine for TLC detection (it's the only trick that worked for me few years ago when I was facing a similar problem with sugars separations), or phosphomolybdic acid. A preparative TLC following the indications of Muruganantham should work.

perhaps you can have a look at this document, it contains helpful solutions:

http://chemwiki.ucdavis.edu/@api/deki/files/3816/=TLC_plate_visualization.pdf

gook luck!

I recommend separation by column chromatography using ethyl acetate/hexane mixtures in gradient elution as mobile phase and visualization of components in fractions by TLC plates sprayed with sulfuric acid solution (25%v/v) or immersion in sulfuric acid solution (10%v/v) or iodine vapor as TLC visualization reagents.

I belive 10% H2SO4 in Ethyl alcohol and subsequent charring should do the trick. CAN might be a good choice also. There´s a Merck book of developing stains for chromat. maybe you can get it. best wishes, Juan

Check their speraration on C18TLC (Methanol /Water) if it works , go a head and use C18 column chromatography.

I would suggest flash chromatography in ethyl acetate/hexane; you can check tlc with iodine or H2SO4 10%sol. If the Rf of compounds are very similar to each other, you can use a gradient elution or a preparative TLC with the same solvent mixture... good luck :)

I would suggest flash chromatography or dry-column flash chromatography (Vogel´s; fith edition, pages 216-217) with ethyl acetate/hexane gradient, and detection by TLC with iodine vapour.

If these methods were not satisfactory, you could try preparative TLC with the same solvents or ethyl ether/hexane.

You should use refractive index detector attached to HPLC. For TLC you can use iodine jar or iodine solution or vaniline solution. Good luck.

First of all you are asking for which chromatography method to follow...?? now chromatography method solely depend upon your need. Means how much quantity of terpenes you are aiming that decides your method of separation.

Generally, if you need lesser amount, then preparative TLC is the best method as we can check by spraying with Anisaldehyde in sulphuric acid (as people explain before you should follow the same trick)

If you are needing even more then go flash chromatography or column chromatography (but detection method is ultimately running TLC of several fractions as several terpenes are UV inactive)

While talking about HPLC then you should go for preparative HPLC normal HPLC will not solve the purpose.

Apart from all things explained above TLC is faster in case of optimization and also economical. GOOD LUCK FOR YOUR STUDY.

For all, thank you very much for your support ...

For TLC reagent :

0.5 mL of anisaldehyde in 50 mL of AcOH anhydrous + 1 mL H2SO4 . after heating terpene = purple color

or SbCl3 (25 g) dissolved in CHCl3 (75 mL). heat or see in UV

SbCl3 (20 g) dissolved in a mixture of AcOH anhydrous (20 mL)/CHCl3 (60 mL).

If you have a good system of TLC solvent try to use preparative TLC and one of these reagents.

Good luck

Thank you ^^

Small modification: anisaldehyde: 0.5 mL; EtOH: 50 mL; Conc. H2SO4: 1 mL. Use it as a spray. Violet with most terpenes and alcohols; orange with ketones.

You can use 5% sulphuric acid in methanol as derivatising agent which gives pinkish turns to light brownish colour for triterpenoids.....for the solvent system your choice is right you can also try for the toluene:ethylacetate:methanol combination(7:3:1)or other modifications of gradients

Thank your for all sharing.

Flash with TLC or evaporative light scattering detector.

Carla, Use PMA stain for TLC, on heating on hot gun, triter pens gives blue color.....just try and see...best wishes.

Thank you

We have to choose a nondestructive visualisation technique for TLC- Carla is observing that all the triterpene spots are UV insensitive. If one goes for HPLC, RI detector has to be used. On TLC, spray with distilled water- you will find opaque bands (triterpenes and other hydrophobics will give you opaque bands).

If you want to use destructive reagents, cut one edge of the TLC plate, spray and then match to cut the un-sprayed main part of the TLC plate.

Hello Carla,

When you have run your TLC, try spraying or dipping or applying with pipette to the plate a solution of 10% Phosphomolybdic Acid in Ethanol. This should give you a green-yellow plate as it dries. Then heat the plate with a hot-air gun -you may then see your triterpenes as distinct spots. Or stand the plate after running in a tank containing a few crystals of Iodine.

John Johnson

Thank u so much

Use liberman reagent as detecting agent.

I think you can run your sample in a suitable solvent system then develop by a 10%  sulphuric acid- ethanol reagent and heated at 120 degrees C for 5 minutes. After visualisation, calculate Rf values and do a preparative TLC and scrap the required spots. If required, you can cover a portion of the plate (vertically) and spray the reagent to avoid reaction to all portion of the spot.