OPTIMIZATION OF THE EXPERIMENTAL CONDITIONS AND THE COLUMN DESIGN PARAMETERS IN DISPLACEMENT CHROMATOGRAPHY

Optimization of the experimental conditions (sample size, reduced mobile phase velocity and displacer concentration) and the column design parameters (column length and average particle size) was performed for the maximum production rate of either component of a binary mixture. The displacement chromatograms were calculated by means of the equilibrium-dispersive model of chromatography, assuming competitive Langmuir isotherms. Binary mixtures of separation factor 1.2, 1.5 and 1.8 and relative concentrations 3:1 and 1:3 were studied. For the systems studied, no optimum displacer concentration was found, the maximum production rates being achieved at the highest displacer concentration allowed by its solubility. The optimum column characteristics depend strongly on the separation factor and on the mixture composition. The maximum production rates were achieved at a much lower value of the retention factor than usually chosen in displacement chromatography. The optimum value of the retention factor of the less retained component was found to be between 1.2 and 2.0, depending slightly on the mixture composition and more strongly on the separation factor.