For phenolic extraction use 70% Methanol or 70% ethanol

Use Methanol

For extraction of phenolics use aqueous solvent like methanol, acetone and ethanol or by using hot water 80-90 degree C u can also get phenolics by green and efficient methodology followed by partial purification using partition chromatograpgy using immisible solvents. In this way u can get extract inriched with phenolics.

Generally, methanol or ethanol works for me. Some phenolics (tocopherols are an example) are non-polar and would be better extracted with ethyl acetate, hexanes, or similar non-polar solvent.

I am more into the green extraction technologies, so an aqueous mixture of solvent like ethanol and water under pressure and temperature gives comparable if not better results!

Hi, three years ago I worked with phenolic compound and I tried a green extraction with water and ultrosonic extraction, but was necesary to add ethanol or methanol, because the recoveries were very low.

Yes, I agree that it is important to with ethanolic solvent mixture. I believe you can avoid methanol if you want to keep it green!

You can use methanol for preparing total extract and then extract n-butanol fraction to separate some of them, targeting phenolic compounds purification.

A mixture of methanol/acetone/water will release most of the soluble phenols with subsequent partitioning in ether/ethylacetate. But, depending on the sample you're working with (we work on cereal flours), you wll need more aggressive strategies to release the bound and conjugate fractions. Hydrolysis with NaOH is reccomended prior to partitioning. If it can help, feel free to contact me

Firstly you use water for extracting phenols. Use n-Butanol to separate water immisible parts. After separate aqueous phase, then you simple dried out your aqueous phase via rotary evaporatory. Now you treat your dried extracts with 100% MeOH.

I found ion exchange columns work well (SAX, strong ion exchange).

For examples, please see:

http://www.isco.com/WebProductFiles/Applications/101/Poster_and_Paper_Reprints/Purification_of_Phenolic_Flavonoids.pdf

http://www.isco.com/WebProductFiles/Applications/101/Application_Notes/AN87_RediSep%20Rf_SAX_Column_Applications.pdf

do we must use a mixture of water and ethanol? is it a necessary step?

I'm working on green coffee and I plan to use 70% ethanol

It all depends on the solubility of you compounds of interest and the extraction technology and method!

If extracting chlorogenic acid, why does it requires water?