Improved reversed-phase gradient retention modeling.

An empirical nonlinear equation is used to describe the relationship between chromatographic retention and solvent composition in both isocratic and gradient chromatography. The integration of the gradient equation can be solved with our equation, allowing a simple transition between isocratic and gradient conditions. Precise interpolation between experimental data points and reasonable extrapolation outside the directly measured data range are possible. Also, the dependence of the parameters of the equation on temperature has been explored, allowing the simultaneous exploration of temperature, gradient starting composition and gradient slopes. A unique quality criterion is used to judge the quality of the separation. Copyright 2010 Elsevier B.V. All rights reserved.