Dear Kouame Mathieu

The best method based on my expertise is the use of serial extraction with solvents having different polarities. Please find the attached files which may help you further.

Regards

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Methanol

Use partitioning chromatography, by changing the polar to non polar solvents, or from less polar to high polar. In general prepare aqueous extract and partition it with methanol, then you can go for ethanol only absolute.

Thank you !

if it is leaf ensure extraction of chlorophyll first then follow Ravi suggested most time before getting to this polar solvents the chlorophyll might have been extracted with the polar solvent. So i will advise you start from non polar to polar.

Sequential extraction using solvents of different polarity starting from non polar to polar solvents. Good luck

Serial extraction with soxhlet method using solvent of different polarity. viz. Hexane, chloroform, methanol/ethanol. methanol/ethanol-water (1:1). etc. the same sample 1st extracted with hexane, then chloroform, then methanol/ ethanol and so on. 

For high yield you can used Ultrasonication and microwave assisted extraction or super critical fluid extraction with similar way as state above.  

For best yield go for hydroalcholic extraction (Ethanol 50% + Aqeous 50 %).