yes you can use 70% acetone or you can use 70% methanol for catechins in tea. If you have any question, you can ask me.

gudluck

:)

Chloroform for alkaloidal extraction. :)

Chloroform for caffeine extraction from tea as said above by Darwin

I am using 70% acetone on my other extractions. Glad to hear that I can apply those on tea. How about DCM?

well, will depend what you´re planning. For instance, if you want check it out which compounds are present in the very polar fraction, the one that simulates the ordinary drink, you may use the soxhlet and a system ethanol-water 50%. In other hand, if you want do a screenning you will need use different systems with a progressive increase of polarity, maybe start with hexane, then dichloromethane or chloroform, then ethanol (both percolating in enviroment temperature) just after that you can use heat(soxhlet) for extraction.

You will probably need a hi-polarity solvent for the heterocyclic compounds in tea, like DMF, DMAC or DMSO. However these solvents are difficult to get rid of also.

If you want to extract catechins then go for 70%acetone or 70% methanol and if you want to extract caffeine then go for chloroform. For flavour extraction you can use DCM in SDE.

Thanks for all your input. I think I'll try 70% acetone first, and then use more polar solvents after.