The Quaternary Case Paper VI

There are, so far, only two reports on the determination of isotherm data from mixtures containing more than two components. In both cases, the FA method was used for ternary mixtures [135, 136], There are no reports on the experimental determination of adsorption isotherms for quaternary mixtures using any chromatographic method. The competitive quaternary adsorption isotherm parameters could be very valuable for the separations of the four isomers of a compound with two chiral centers, or for the preparative separation of two compounds in the presence of one or two impurities. 

The agreement between the experimental and calculated profiles was great in all cases and the overlaps between simulated and experimental data were all between 91 to 96 %. 

To conclude, in paper VI were for the first time ever the adsorption isotherm parameters successfully determined for a quaternary mixture. This was done using the newly developed injection technique with the PP method. Accurate adsorption isotherm parameters were determined without the need of pure components in large quantities. With our injection technique only about 0.3 mg of two of the components have to be available in 

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