First of all you need to search in literature the plants you're working with to have an idea of what type of mono- or diterpene you have. Depending on the terpene type and dyeing reagent, you will obtain different colours, but in the majority of cases they are not specific, e.g.:

1) 0.5 mL anisaldehyde in 50mL glacial acetic acid plus 1mL conc. H2SO4; brown spots for diterpenes (Phytochem Anal. 2012;23(2):184-9)

2) vanillin reagent (50 mL of reagent grade ethanol, 0.3 mL of

reagent grade sulfuric acid, and 1 g of vanillin (‡98.5% HPLC

Grade), and then slowly heating on a hot plate; pinkish-purple spots (not specific, because you can obtain this colour with different terpene types) J Forensic Sci. 2009 May;54(3):612-6.

3)vanillin-H2SO4 solution (1 g vanillin dissolved in 100 mL 1% H2SO4) and heated at 85°C on a plate heater; dark blue spot for linalool, purple or blue for cineol & caryophyllene, depending on the concentration (Chem Cent J. 2012; 6: 46).

In order to differentiate between mono- or diterpene, you have to carry out other analysis like NMR ou GC.

The most reliable method to differentiate sesquiterpenes from diterpenes is without doubt the GC and or GC-MS methodology. In the light of the possibility of the laboratory, if this cannot afford this type of apparatous, I believe that also a trivial TLC system can be suited for this purpose: for this it would be necessary an accourate glance of the published literature.

Look in book Thin-Layer chromatography: Reagents and detection methods by Jork F. Wimmer F. for suitable detection reagnet. Best regards

I have never used this system before but I saw in "Dyeing reagents for Thin Layer and Paper Chromatography", E.Merck, Darmstandt, Federal Republic of Germany, 1980

Antimony (III) chloride- acetic acid for steroids and diterpenes.

Spray solution : Dissolve 20 g antimony trichloride in a mixture of 20 ml glacial acetic acid and 60 ml chloroform.

Treatment: Heat 5 min at 100 C

Diterpenes show red-yellow to blue-violet spots.

Inspect in long-wave UV light.

Literature:H.P. Kaufmann, AK. sen Gupta, Chem.Ber. 97, 2652 (1964)

Chemical:

-antimony (III) chloride GR, Cat.No.7838

-Acetic acid glacial min. 96% (1.06) GR, Cat.No. 62

-Chloroform GR, Cat.No. 2445

Good luck ^_^

Dear Ammar, I agree with Atallah, in TLC the appearance will only depend on the functional groups. In this sense, only sesquiterpene lactones can be easily differenciated from the rest with the Kedde Reagent (only interference may be lactone ring of cardenolides):

3,5-dinitrobenzoic acid + NaOH → violet/pink colour

the problem with Kedde is that (1) it's based on a water solution, and it damps badly the TLC (2) it fades out quickly and may give very faint positives. The water must be very pure as metal traces may react with kedde and give violet backgrounds which makes it even more difficult to detect the STLs.

I will send to you a copy of Rios, JL, Simeon, S., Jimez, FJ, Zafra-Polo, MC and Villar, A. (1986) Reagents for screen- ing medicinal plants by thin-layer chromatography. A review.Fitoterapia tomorrow. Best Wishes

A problem I did not think of all these years! I do not think there is any color reaction that can distinguish between sesqui and diterpenes. May be as Prof.Woodward said in his Nobel lecture , this could be an opportunity to study the problem. As far as I can see , it is difficult.

Triterpenes and steroids can be distinguished from each other and from lower terpenoids by Liebermann-Burchard reagent (Sulphuric acid -acetic anhydride).

GC-MS (not GC) and 1H NMR and 13C NMR can distinguish these two groups- but a little careful study would be required in some cases. The number of skeletons, modified skeletons and the functional groups make it very complex.

First of all you need to search in literature the plants you're working with to have an idea of what type of mono- or diterpene you have. Depending on the terpene type and dyeing reagent, you will obtain different colours, but in the majority of cases they are not specific, e.g.:

1) 0.5 mL anisaldehyde in 50mL glacial acetic acid plus 1mL conc. H2SO4; brown spots for diterpenes (Phytochem Anal. 2012;23(2):184-9)

2) vanillin reagent (50 mL of reagent grade ethanol, 0.3 mL of

reagent grade sulfuric acid, and 1 g of vanillin (‡98.5% HPLC

Grade), and then slowly heating on a hot plate; pinkish-purple spots (not specific, because you can obtain this colour with different terpene types) J Forensic Sci. 2009 May;54(3):612-6.

3)vanillin-H2SO4 solution (1 g vanillin dissolved in 100 mL 1% H2SO4) and heated at 85°C on a plate heater; dark blue spot for linalool, purple or blue for cineol & caryophyllene, depending on the concentration (Chem Cent J. 2012; 6: 46).

In order to differentiate between mono- or diterpene, you have to carry out other analysis like NMR ou GC.

I agree miss Margareth Gallo. You will have purified your extract and after carry out with NMR or GC/MS. Maybe just GC/MS.

Ammar, to distinguish between diterpenes and sesquiterpene you wil need to make use of both the GLC/GC and TLC. If you can get this book " Phytochemical Methods; A Guide to Modern techniques of Plant Analysis" by J.B. Harborne.

Yes there is a spraying reagent (Absolute Ethanol: Glacial acetic acid: Sulphuric acid: Anisaldehyde ; 84.5: 10: 5: 0.5) which can be used to distinguished sesquiterpenes & diterpenes spots on TLC plate.

Thanks to all for their valuble replies.

I think best spray reagent for

sesquiterpenoids : Anisaldehyde-sulphuric reagent

and for diterpenoids : 5%-Aqueous –sulphuric acid

DrGP: That is when you have only these two groups. Even not applicable to all in each group. What will happen if you have steroids and triterpenoids? It is often not possible to separate all di and sesqui from triterpenoids and steroids! I feel a combination of GC-MS and NMR is the only dependable solution. Pl consider.

i agreed with the Bapuji,

I agree with Dr. Bapuji too.

No that I am aware of. Spray reagents are usually functional group reagents. i.e, they react with functional groups present in your molecule. Sometimes the color of the spot will also tell you something about the nature of the FG involved; thus, anisaldehyde gives shades of blue with alcohols, no matter they are part of mono, di or triterpenes, whiche it will yield orange type spots with aldehydes and ketons, etc.