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An AGP-based chiral stationary phase has been applied successfully for enantioseparation of 4(3H)-quinazolone derivatives. Chiral-AGP is proved to be an excellent selector, as optimized chromatographic conditions allow with one exception baseline resolution for the enantiomers of the potential cholecystokinin antagonist compounds (alpha = 1.19-1.85). Retention and enantioselectivity could be modified to a large extent by varying the eluent pH and adding organic solvents with different types i.e. acetonitrile and 2-propanol to the buffered mobile phase. It was established that by increasing the eluent pH from 6.0 to 7.0 the retention factors of of the model compounds bearing no protonable groups are increased in the presence of 7 v/v % (1.33 M) acetonitrile. However further increasing the acetonitrile content up to 10 v/v % or addition of 2-propanol in equimolar concentration (1.33 M) no similar changes could be detected with the same modification in the eluent pH. These observations are explained by changes in the sorption properties of the selector determined simultaneously by the type and concentration of organic modifier and also the eluent pH. The experimental data give further insight into the chromatographic mechanism on a Chiral-AGP column.

After the survey and characterisation of the solid/liquid chromatographic methods, the author summarized the features of overpressure layer chromatography; the disturbing zone and the multi-front effect as well as the elimination of their influence. In light of these effects, the strategy of the mobile phase transfer possibilities is demonstrated between the various analytical and preparative liquid chromatographic methods, with the OPLC playing a central role. The main point of this strategy is that the examination of biological matrices is always begun with unsaturated TLC chamber, in which the compounds to be separated are placed between the Rf values of 0.3 and 0.8. The optimized TLC mobile phase is transferred without changes to the OPLC technique where a prerun is applied. For separation of nonpolar compounds, the prerun can be performed with hexane; for separation of polar substances the prerun can be performed with any component of the mobile phase in which the components are unable to migrate. The selection of this solvent might be considered during optimization of the mobile phase. Using HPTLC chromatoplate and analytical OPLC technique, highly effective separation can be achieved. The scaling-up for the various preparative chromatographic systems can be performed on basis of the applied chromatographic circumstances. The dry-filled preparative (FC, LPLC, MPLC) columns can be equilibrated with the solvent used for the prerun in analytical OPLC, while in case of filling with slurry technique, the slurry has to be prepared using the same solvent as was used for the prerun of OPLC. The air bubbles can be eliminated in both cases by pumping over the appropriate quantity of the solvent used for prerun, afterwards the preparative separation can be started with the optimized unsaturated TLC mobile phase. The author deals separately with the mobile phase transfer possibilities between the different analytical and preparative planar (OPLC and RPC with various chamber types) chromatographic techniques, where the saturation of the vapour phase is the determinant. The strategy is demonstrated through various plant extracts. The mobile phase transfer possibilities between the different solid-liquid chromatographic methods are summarized in comprehensive figures. Figure 13 demonstrates the direct transfer possibilities, different lines show those applicable with various methods: dotted line stands for off-line and thin line for on-line methods, while the ones marked with thick line ensure the transfer of the optimized mobile phase without change between different solid-liquid planar and column chromatographic techniques in case of both--off-line and on-line--procedures.