Nonlinear direct inverse method: a shortcut method for simultaneous calibration and isotherm determination

This work addresses a way to combine isotherm determination and nonlinear calibration. In this method, like the classical inverse method, experimental elution profiles are compared with the results of a detailed model that accounts for nonlinearity in equilibrium, axial dispersion, and mass transfer kinetics. However, unlike the classical inverse method, the calibration of detector is carried out simultaneously with isotherm determination thereby reducing cost and saving time. In this study no limitation is imposed on the linearity of the detector signal or on the overlapping of elution profiles for the separation of enantiomers. The method has been experimentally validated for the separation of a mixture of guaifenesin enantiomers over a wide range of concentration.