OPTIMIZATION OF THE EXPERIMENTAL CONDITIONS IN PREPARATIVE LIQUID-CHROMATOGRAPHY WITH TOUCHING BANDS

Relationships are derived between the sample size permitting the elution of the components of a binary mixture as two touching bands and the parameters characterizing the separation and the column performance. These equations take into account the competitive interactions of the mixture components. They permit the determination of the optimum experimental conditions for maximum production rate with touching band elution. The production rate increases monotonically with increasing inlet pressure available, provided that the column of optimum characteristics is used. For a given column, there is an optimum flow velocity and hence an optimum inlet pressure. Because of the competition between the mixture components for interaction with the stationary phase, the production rate under touching band conditions can be larger (under conditions of a predominant displacement effect) or lower (under conditions of a predominant tag-along effect) than the value derived when this competition is ignored. © 1990.