Estimation of adsorption isotherms using nonlinear frequency response of a chromatographic column : experimental study

Experimental study of a nonlinear frequency response of a chromatographic column to variations of the input concentration, performed using a standard HPLC instrument and a test system silica/cyclopentanone, is presented. The experiments were performed with variations of the input concentration in a square-wave form, for different steady-state concentrations, frequencies and amplitudes of the input change. A procedure for estimation of the first, second and third order frequency response functions from experimental data was developed. A critical analysis of the experimental procedure, from the point of view of the applicability of the nonlinear frequency response to estimation of adsorption isotherms, is given