| Summary: | 碩士 === 國立交通大學 === 應用化學系 === 90 === Two methods which are used to separate chitooligosaccharides are HPLC and CE, but they cannot handle great sample volume either. In this study, we try to separate and collect chitooligosaccharides in either of aqueous two phase solvent system and organic/aqueous solvent system in countercurrent chromatography. Experimental factors are composition of solvent, sample concentration and pH value. As the result, in aqueous two phase solvent system, chitooligosaccharides with low molecular weight and high polarity are hardly separated while they almost stay in the upper layer, PEG(polyethylene glycol) - rich phase. Even though we increase the molecular weight or concentration of PEG, add different kinds of salts including phosphate and citrate, change the concentration of salt, or lower the pH value in solvent system, chitooligosaccharides cannot be eluted out. It is suggested that a good affinity exists between chitooligosaccharides and PEG. In organic/aqueous solvent system, however, no matter how greatly we try to increase the polarity or the pH value of our solvent systems, the partition coefficient of chitooligosaccharides between the two phase cannot be increased, so they remain in the aqueous phase.
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