1. Chloroform(CHCl3)–methanol–water (4:3:2) 0.071
2. Ethyl acetate–ethanol–water (10:2:10) 1.233
3. n-Hexane–ethyl acetate–ethanol–water (4:4:3:2) 1.579
4. n-Hexane–ethyl acetate–methanol–water (3:4:2:1) 0.821
5. n-Hexane–ethyl acetate–methanol–water (6:8:4:2) 0.862
Experimental protocol: A small amount of the crude sample 1mg was added to 2.0mL of the mixture containing equal volume of each phase of the two-phase solvent system in a test tube, and the contents were mixed thoroughly. The test tube was caped and shaken vigorously for 2min to equilibrate the sample thoroughly. An equal volume of each phase was then analyzed by HPLC to obtain the partition coefficient (K). The K-value was expressed as the peak area of the compound in the upper phase divided by the peak area of the compound in the lower phase.
Table 1: The K (partition coefficient) values of solvent systems tested.