For optimum extraction of a compound, the textbook says "The main selection criteria is the polarity of the solvent in relation to that of the analyte. The maximum Kd value occurs when the polarity of the extraction solvent matches that of the analyte".

I can check the polarity of the organic solvent from the table. However, I forgot (I might have learned from Chemistry Courses)how to calculate the polarity of the analyte. Please advise!

Thank you!

Doing the calculation might be an interesting exercise, but when all is said and done there are but a handful of commonly used extraction solvents-aromatic(toluene), ether, ethyl acetate, chloroform or methylene chloride, hexane. These are commonly used because they work for about everything and they have other useful properties as an extraction solvent-boiling point, purity,cost, etc. Odds are that if something can be extracted from water one of the entries on this list will do it. These same solvents wind up being the things to also use for extracting polymers and numerous other applications.

I agree with Bill. You will have to check recovery anyway, so an empirical approach is the method of choice.
However, if you find a method to calculate a value that is comparable to the polarity indices for solvents (apparently empirically determined) let me know! Nobel is waiting.

Thanks for your help. I sometimes find that the art of chrmomatography is a "trial and error" process!