Development of mass transfer model for chromatographic separation of free lutein and fatty acids in de-esterified marigold lutein

Abstract

This article was aimed to construct a mathematical mass transfer model for chromatographic separation of free lutein and fatty acids in de-esterified marigold lutein. Required model parameters: adsorption isotherm, overall mass transfer and axial dispersion coefficients, were first determined. The adsorption isotherms of the compounds were studied using batch adsorption experiments, while the axial dispersion and overall mass transfer coefficients were determined from published empirical-correlation and correlation developed experimentally from this study, respectively. The adsorption isotherms were found to be linear within the equilibrium concentration of ≤100μg/ml. The isotherm constants of fatty acids were about twice those of free lutein. The isotherm constants and the mass transport parameters were then applied to the mass transfer model. The predicted results were compared with the experimental data at the optimum mobile phase velocity (0.16cm/s). Good agreement was found, i.e., the average absolute deviations were less than 2% and 7% for semi-preparative and preparative columns, respectively.