Preparation of a Hydrophilic Stationary Phase Immobilizing an Acetylated Diallylamine_Acrylamide Copolymer and Its Retention Characteristics for Water-soluble Compounds

Abstract

A new hydrophilic stationary phase (Ac-DAA resin) that was acetylated after immobilizing a diallylamine-acrylamide copolymer into a hydrophilic base resin was prepared. The retention characteristics for the water-soluble compounds on the Ac-DAA resin were evaluated by comparisons with the diallylamine-maleic acid copolymer immobilized stationary phase (DAM resin). The copolymer-immobilizing content of the Ac-DAA resin was approximately 2.5-times higher than that of the DAM resin, but the contents of holding-water and hydration water were almost the same. Water-soluble compounds, such as nucleobase, nucleoside and glucoside, were clearly retained on both stationary phases by hydrophilic interaction. However, for the nucleobases, the specific affinity, which was estimated to be a hydrogen associativity, was observed in the Ac-DAA resin. Further, the strength of the electrostatic interaction in both stationary phases was compared using ionic water-soluble compounds as analytes. The electrostatic interaction of the Ac-DAA resin was stronger than that of the DAM resin. However, by adjusting the buffer solution pH of the mobile phase above 8, the electrostatic interaction of the Ac-DAA resin could be suppressed without a decrease of retention based on the hydrophilic interaction. It was concluded that the Ac-DAA resin was effective for the separation of water-soluble compounds including ionic compounds by employing the mobile phase adjusted with an appropriate pH. © 2012, The Japan Society for Analytical Chemistry. All rights reserved.