Optimization of ternary mobile phases in reversed-phase thin-layer chromatography by use of a mixture-design approach with the solvation-parameter model

The retention factors for a varied group of solutes were determined on cyan opropylsiloxane-bonded silica layers for five binary and ten ternary mobile phases containing methanol, acetonitrile, and water. A retention model was formulated at each composition using the solvation-parameter model. A mixt ure-design approach was then used to model the individual system constants as a continuous function of mobile phase composition, producing system surf aces from which retention surfaces could be calculated for method developme nt. Regression analysis for the full data set indicated that the mixture-de sign models can be used to estimate solute migration properties with accura cy similar to that of the original solvation-parameter models. The predicti ve ability of the mixture-design models is demonstrated for the estimation of retention factors for solutes and mobile phase compositions not used to construct the original models.