Study on the accuracy of the elution by characteristic point method for the determination of single component isotherms

The accuracy of the method of elution by characteristic point (ECP) used to determine single component isotherms was studied numerically. Overloaded e lution peaks were calculated using the equilibrium-dispersive model of nonl inear chromatography while varying the four parameters, i.e., the number of theoretical plates, the dimensionless Langmuir equilibrium constant, the r etention and the loading factor, involved in the fundamental equations of t he problem. Single component isotherms were estimated by analyzing the diff use profile of the elution peaks by the ECP method. Similar results were ob tained with the transport-dispersive model. The comparison of these calcula ted isotherms with the initial Langmuir isotherms provided detailed informa tion on the influence of the mass transfer resistances on the accuracy of t he isotherms afforded by the ECP method. The systematic error made on the i sotherms depends on the experimental conditions, described by the four para meters. It is expected that this error could be eliminated by correcting th e influence of nonequilibrium in the column on the basis of results of the nondimensional calculations. The concentration range of the objective isoth erm which can be determined by the ECP method can also be predicted by nume rical calculations. The usefulness of the correction strategy and the predi ction of the concentration range were experimentally demonstrated. (C) 2000 Elsevier Science B.V. All rights reserved.