[en] For optimizing a liquid chromatographic method, direct modeling some responses like minimum resolution is sometimes difficult to perform. By modeling the retention time at apex and the times associated to 13.4% of the peak height, it is possible to obtain estimations of these responses using an adequate cascade of equations, these equations being the definitions of these responses. As a multi-criteria decision has to be taken in most of these optimizations, a Derringer's function can be defined for each response of interest and a overall desirability, on which the final is taken, can be derived. In addition, the chromatogram in any experimental point can be predicted. (C) 2004 Elsevier B.V. All rights reserved.