Prediction of a suitable mobile phase composition in reversed-phase high-performance liquid chromatography using fragmental constants

An expert system is described that proposes an optimal mobile phase composition in reversed-phase high-performance liquid chromatography. This is achieved by predicting the retention index of the compound of interest from fragmental constants. Using a calibration line, set up with reference compounds, it is possible to infer from the retention index the percentage of organic modifier in the mobile phase that will result in a capacity factor between three and ten. The expert system can be trained to find optimal retention index values for newly defined fragments based on a set of compounds with known retention index.