Separation of Water-Insoluble and Neutral Linear Synthetic Polymers in Nonaqueous Capillary Zone Electrophoresis Using Phosphonium-Based Ionic Liquid

The separation of neutral and water-insoluble linear synthetic polymers in non-aqueous capillary zone electrophoresis using the hydrophobic phosphonium-based ionic liquid trihexyl(tetradecyl)phosphonium chloride (P66614Cl) were investigated using polystyrene, polymethylmethacrylates, polybutadiene, and polycarbonate as test analytes. The solubility of P66614Cl in tetrahydrofuran was above 500 mM, which was significantly higher than that of the general ionic surfactants used in our previous studies. The separation of the four polymers was achieved using a binary mixture of tetrahydrofuran/methanol or tetrahydrofuran/acetonitrile containing P66614Cl as the electrophoretic medium. It was confirmed that an increase in hydrophobicity or bulkiness of the cationic reagent improved the polymer separation. The interaction between polycarbonate with P66614Cl was reduced by the addition of acetonitrile, and enhanced by the methanol addition.