METHOD DEVELOPMENT BY AN EXPERT-SYSTEM - ADVANTAGES AND LIMITATIONS

Several approaches can be used for the prediction of the optimum eluent composition in RP-HPLC, but only a few are known that use the structure of the solute. The latest release of the computer program EluEx, version 3.0, was developed to help the chromatographer in practical work. The program is based on the prediction of the pK(2) and log P (logarithm of 1-octanol-water partition coefficient) values of the solutes. The first eluent suggestion can be done without any preliminary practical work, based on the structural formulae of the solutes. In our experience, two or three experiments are usually sufficient to determine the optimized binary conditions. The surface heterogeneity and the diversity of RP columns, such as the effect of silanol interaction, can be handled by the program only to a limited extent. If the difference in hydrophobicity between two compounds is small, the elution order cannot be predicted properly in all instances. The same is true for some isomers, e.g., diastereomers. In this paper, the results of applying the program to some neutral, acidic and basic solutes are summarized.