Ethyl Acetate extraction...i forget how to do it..help!

[seamoro]

I performed an methanol extraction of a material. Now i must do further extraction with a mixture of ethyl acetate and water (1:1) to give an ethyl acetate-soluble fraction (EAE) and an aqueous-soluble fraction (AE).
Last time i did this i remember using a separating funnel in which i separated the EAE and AE. But do i just pour the ethyl acetate and water in the round bottom flask containing the methanol extract and swirl it around and then pour that into the funnel and perform the separation?...obviously do this a number of times...is this correct or am i missing something...Thanks in advance

[Alexandre]

I suspect it is needed to be evaporated to dryness to get rid of MeOH. It can be done on rotary, for example.
Then extract with 1:1 EtAc/W. Otherwise at a certain ratio of MeOH/EtAc/W it will be one phase.
If you need to do it few times – repeat. You may need to wash EtAc and W fractions with few mLs of saturated W and EtAc accordingly if purity/recovery/yield are important.

[seamoro]

thanks very much....but one more question...........the methanol extract that has been rotary evapourated....i just pour in the ethyl acetate/water in with the extract and swirl around to disolve it?

[Alexandre]

If your protocol says - extract with EtAc/W 1:1, then it is. You may need to repeat 2-3 times.

If there is some water left after you get rid of metho – add equivalent amount of EtAc.
If it is only a few mLs of water and you want some practical volumes for separation, e.g. 25- 50 mL, then scale it up. Most of the times you don’t need large amounts of solvent if your stuff dissolves well in etAc. Keep in mind the environment too.