N-(polyethyleneglycol monomethyl ether)-N-methylmorpholinium-based background electrolytes in capillary electrophoresis

A homologous series of N-(polyethyleneglycol monomethyl ether)-N-methylmorpholinium hydroxides has been synthesized, characterized and used as the source of cationic co-ions in mobility-matching background electrolytes designed to eliminate the efficiency-degrading effects of electromigration dispersion. The mobilities of the new cationic co-ions vary in the 6.10(-5) to 35.10(-5) cm(2)/V s range in 25 mM mobility-matching background electrolytes, prepared from phosphoric acid and the respective N-(polyethyleneglycol monomethyl ether)-N-methylmorpholinium hydroxide. It is demonstrated experimentally that electromigration dispersion-related peak broadening can be minimized and difficult electrophoretic separations can be realized without significant alteration of the separation selectivity when these N-(polyethyleneglycol monomethyl ether)-N-methylmorpholinium cations are used as co-ions in mobility-matching background electrolytes.