Aggregate of Amphiphilic Block Copolymer as a Pseudo-Stationary Phase in Capillary Electrophoresis

The use of an aggregate of amphiphilic block copolymer 1, which consists of poly[(N-acetylimino)ethylene] and poly[(N-pentanoylimino) ethylene], for a pseudo-stationary phase in capillary electrophoresis has been examined. From gel-filtration chromatography, the aggregate from 1 (1-AG) was found to incorporate phenol. When the running solution contains 1-AG and sodium dodecyl sulfate (SDS), the electrophoretic mobility of phenols increases as the concentration of SDS is raised. In the absence of either 1-AG or SDS, the electrophoretic mobility becomes nearly zero. Thus, it is found that when 1-AG and SDS are added to the running solution, SDS is incorporated in 1-AG, giving negative charges on the 1-AG, which works as a pseudo-stationary phase. By the addition of 1-AG and a low concentration of SDS in the running solution, six phenols are separated and the migration order of phenols is basically dependent on their lipophilicities. However, the migration order of some phenols is different from that in the micellar electrokinetic chromatography (MEKC) using a high concentration of SDS.