I think (ethyl acetete : n-butanol:water:1%formic acid)

(70:20:10)

Thank you

It really depends on the compound you wish to purify. Non-polar flavonoids may be purified with hexane/ethyl acetate, more polar ones need dichloromethane and methanol. Reverse phase also works well.

Please see this application note that I wrote:

https://www.teledyneisco.com/en-us/liquidChromatography/Chromatography%20Documents/Application%20Notes/Purification%20Strategies%20for%20Flavones%20and%20Related%20Compounds%20App%20Note.pdf

Polyamide can work for these compounds, too:

https://www.teledyneisco.com/en-us/liquidChromatography/Chromatography%20Documents/Posters/Purification%20of%20Phenolic%20Compounds%20Using%20a%20Combination%20of%20Flash%20and%20Preparative%20Chromatography.pdf

The HPLC runs show that another purification step would have been helpful, in this case.

Ethanol and ethyl acetate are the best option for Kaempferol. Actually selection of Mobile phase depends on polarity of the compounds.

Thank you all of you