ABSTRACT

Heterocyclic bases as pharmacologically active  compounds, widely used as pharmaceuticals and synthetised as secondary methabolites in plants, are the subject of scientific interests. Therefore, it is necesary to analyse these organic electrolytes. Since heterocyclic bases appear in solutions as ionized and unionized forms, they are difficult subject of chromatographic separation. The aim of this paper is to discuss the retention behaviour of model substances such as pyridines and quinolines in the normal and reversed phase systems. The paper^’s emphasis is laid upon chromatographic systems with silica, alumina, magnesium silicate and polar bonded stationary phases with non-aqueous eluents and their use in the analysis of alkaloids, benzodiazepines, barbiturates and other bases. The dependence of retention factor on the pH and modifier concentration in reversed-phase systems are also discussed. The application of RP systems in the analysis of basic compounds is also reviewed with the different methods of suppression of silanols and/or analytes dissociation. The behaviour of heterocyclic bases in systems with ion-pair reagents is also mentioned. The possibilities of optimization of separation by changing the type and/or concentration of ion-pair reagent, modifier, buffer type and pH are also presented. The examples of the use of ion-pair systems in the analysis of alkaloids are reviewed. The use of cation-exchangers in the analysis of basic compounds is also taken into account.