I am doing a research for the isolation, purification and characterisation of polyphenols and other polar compounds from medicinal plant. I have methanol extract of my medicinal plant. I want to do fractionation.so I need a protocol for the series of solvent that can be used one after the other for getting right fractions. What is the best series of solvents and what column should I use for the Fractionation of plant extract?
Dear Abdulelah Ahmed Thabet
You can start with a liquid-liquid fractionation using less polar to more polar solvents (hexane-chloroform-ethyl acetate-butanol and the remaining in water)
1- re-suspend your extract in water
2-wash your suspension with hexane and separate in a funnel; and repeat until the hexane added remain clear before passing to chloroform... and so on
and then check each fraction for its polyphenol content, they should be present either in ethyl acetate and/or butanol fractions and in lesser amount in the water fraction.
For column fractionation, you should standardize your solvent system yourself using analytic TLC. For this purpose you should choose a system of 2 or 3 miscible solvents (1 less polar and other (s) more polar) and check their ability to separate your compounds before going for the column.
Regards!
NOBOSSE
Dear Researcher,
Completely agree with Nobosse, While analyzing polyphenols you need some methods. I am attaching some useful documents here of my respected colleges. Good luck
I am also agree with Nobosse and Ajay . The main step after extraction is to isolate the fractions in pure form. This can be done by Column chromatography and TLC. The purity of compounds can be checked by HPLC. Good Luck!
I think all are on the same wavelength , get the aqueous extract , perform the TLC test on a square type ( 4 X 4 inches size ) to check first on a one dimensional side , the behaviour of the extract contents , the the same plate can be eluted on the second dimension . this will show us the no / amount of the impurities being eluted in the first dimension. The solvent system we just have to find out through the trial basis & use that which gives maximum no. of compounds on the TLC plate. The Column chromatography solvent system has to be fairly stronger due to thickness of the silica or cellulose column bed . Collect the column fractions & do their UV , try to separate them as per their behaviour. Separate the one U R interested most , evaporate them for further study & c=hemical characterixzations .
USE TLC to find out best solvent system for separation of your compounds
I agree with the answers of previous researchers
you will find attached an article published recently explains the method of extraction of phenolic fractions by liquid-liquid extracion.
dEAR Abdulelah Ahmed Thabet
FIRST DESIGN BETTER TLC SOLVENT SYSTEM FOR NETTER SEPARATION THEN DO COLUMN CHROMATOGRAPHY IN BEST SOLVENT FOR BETTER SEPARATION.
Dear
In order to make a good choice of the elution system, you can use the spectrophotometer for the UV-Vis analysis (200-800 nm). The results show characterized absorption peaks, corresponding to a specified polyphenols group.
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