Journal of Chromatography A, 1005 (2003) 35–49 www.elsevier.com / locate / chroma Determination of the single component and competitive adsorption isotherms of the 1-indanol enantiomers by the inverse method a,b,1 a,b a,b, * Attila Felinger , Dongmei Zhou , Georges Guiochon a Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA b Division of Chemical and Analytical Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6120, USA Received 7 February 2003; received in revised form 22 April 2003; accepted 22 April 2003 Abstract The inverse method of isotherm determination consists in calculating the numerical values of the coefficients of an isotherm model that give a set of chromatographic profiles in best possible agreement with the set of experimental profiles available. This method was applied to determine the adsorption isotherms of the 1-indanol enantiomers on a cellulose tribenzoate chiral stationary phase. Both single-component and competitive isotherms were determined by using no more than one or two overloaded band profiles. The isotherms determined from the overloaded band profiles agreed extremely well with the isotherms determined by frontal analysis. Several isotherm models were used and tested. The best-fit isotherm was selected by means of statistical evaluation of the results. The results show that the adsorption is best characterized with a model describing heterogeneous adsorption with bimodal adsorption energy distribution.  2003 Elsevier B.V. All rights reserved. Keywords: Adsorption isotherms; Inverse method of isotherm determination; Chiral stationary phases, LC; 1-Indanol; Cellulose tribenzoate 1. Introduction phases (CSP) which often have a relatively low saturation capacity. So, these separations are usually The production of pure enantiomers is one of the executed under strongly nonlinear conditions. Ac- major fields of application of preparative chromatog- cordingly, the accurate determination of the equilib- raphy in the pharmaceutical industry. These sepa- rium isotherms of the two enantiomers on a CSP is rations must be carried out on chiral stationary of fundamental importance to do computer-assisted optimization or scaling up of the process. Several dynamic methods are available to de- termine equilibrium isotherms by chromatography. *Corresponding author. Tel.: 11-865-974-0733; fax: 11-865- The most common methods are the frontal analysis 974-2667. (FA), the elution by characteristic point (ECP), the E-mail address: guiochon@utk.edu (G. Guiochon). 1 frontal analysis by characteristic point (FACP), and On leave from the Department of Analytical Chemistry, the perturbation (injection on a plateau, PM) meth- ´ ´ University of Veszprem, Veszprem, Egyetem Utca 10, H-8200 Hungary. ods [1]. FA is the most popular method, because of 0021-9673 / 03 / $ – see front matter  2003 Elsevier B.V. All rights reserved. doi:10.1016 / S0021-9673(03)00889-6