CHROMATOGRAPHIC OLIGOMER SEPARATION OF POLY(OXYETHYLENES) ON K+-FORM CATION-EXCHANGE RESIN

Compounds having poly(oxyethylene) chains as a part of the structure were separated on a cation-exchange resin according to the number of oxyethylenes by utilizing a difference in the complexation with K+. The retention strongly depended on properties of mobile phases, for example, dielectric constant of the solvent, the concentration of water, the concentration of K+, etc. More than 30 oligomers were successfully separated with the gradient elution from pure methanol to methanol containing K+. in addition, the formation constants of K+ complexes in methanol were chromatographically determined. Logarithms of formation constants linearly increased with increasing number of oxyethylene units. © 1990, American Chemical Society. All rights reserved.