Intermolecular interactions in normal-phase HPLC systems with alcohol hydrocarbon eluents

Summary We apply our new retention model introduced elsewhere to the studies of intermolecular interactions between the solute and the remaining components of a normal-phase HPLC system using a binary mobile phase consisting of an alcohol and a hydrocarbon. This can be achieved through the analysis of the regressional parameters A, B, and C appearing in the relationship of solute retardation (R_F) vs. mobile phase composition. Negative values of these parameters indicate a greater affinity of the solute to the stationary phase than to a given mobile phase moiety, whereas positive values have a reverse meaning. According to the absolute values of A, B, and C solute groups can be arranged according to the affinity toward a given mobile phase moiety, which is a detailed and important information regarding their separation, the stationary phase and with each individual constituent of the mobile phase.