Simultaneous effects of amines and alkylsulphonates in reversed-phase ion-pair liquid chromatography--application to the separation of 2-imidazoline drugs.
The reversed-phase liquid chromatographic separation of several pharmaceutically important 2-imidazoline derivatives using eluents containing both amines and alkylsulphonates, is described. The addition of N, N-dimethyloctylamine and sodium octanesulphonate to an acidic aqueous methanolic eluent, resulted in an eluent with much higher separation power than mobile phases containing only one modifier. The combined effect of the amine and of the alkylsulphonate enabled baseline (or nearbaseline) separations of all the 2-imidazolines studied. The use of such eluents is described in terms of efficiency, selectivity, peak symmetry and separation time and the mechanism of retention is discussed. Some separation examples are given to demonstrate the applicability of the developed technique in the quality control of these drugs in pharmaceuticals.
De Schutter
J A
JA
Department of Pharmaceutical Chemistry and Drug Quality Control, Faculty of Pharmaceutical Sciences, State University of Ghent, Harelbekestraat 72, B-9000-Ghent, Belgium.
Van Den Bossche
W
W
De Moerloose
P
P