Hydrophobic interaction chromatograph optimization

Equations (16.12) and (16.13) are very important, since they easily can be used to predict the influence of any operational parameter on the steepness factor, h, and therefore on the analysis time, efiSciency, and resolution. However, they are based on the validity of Equation (16.10). It has been shown that some deviations occur for some compounds and chromatographic systems (6), especially when retention is not governed solely by hydrophobic interaction. This is, for example, the case when the solutes are strongly basic and the stationary-phase acidity is high. Nevertheless, it is always possible to modify the form of the mobile-phase variation with time in order to maintain the applicability of the linear-solvent-strength theory [Equation (16.1)]. As we have seen above, this type of gradient offers a considerable help in the fundamental understanding of the retention behavior of the solutes and in the optimization of a separation. 

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