Use of Three-Dimensional Minimum -Plots for Optimization of Mobile Phase Composition for RP-HPLC Separation of Sulfonamides

Abstract

The use of mixture designs for the mathematical modeling of the dependence of the capacity factor (k) on ternary mobile phase composition in RP-HPLC was investigated. Regression models for 11 sulfonamides in three ternary mobile phase systems [water:methanol:acetonitrile, water:methanol:tetrahydrofuran (THF), and water:THF:acetonitrile] were calculated. Evidence was found that it is possible to transfer the regression models between columns using the same packing materials. The calculated models were used for the optimization of the separation of three mixtures in these mobile phase systems. The optimization method employed was an extension of the window diagram method of Laub and Purnell to three interdependent variables and non-linear models. It appears that the method is well suited for the optimization of routine analyses because of the large amount of information it provides.