Hydrophobicity parameters determined by reversed-phase liquid chromatography. Xiv. Application of a new hydrogen-accepting scale of monosubstituted pyrazines to analysis of the relationship between octanol-water partition coefficients and retention factors measured in different mobile phases.

We recently proposed a new H-accepting scale, SHA, for monosubstituted pyrazines, and demonstrated that this parameter works effectively in expressing the relationship between logP (P: 1-octanol/water partition coefficient) and logk' (k': retention factor derived from reversed phase liquid chromatography) with aqueous methanol solutions as the mobile phase, according to the equation: logk' = alogP+rhosigmaI+sSHA+const., where sigmaI represents the electronic substituent constant. In this work, we have extended the same treatment to analysis of logk' measured in mobile phases containing different organic modifiers such as 1-propanol, acetonitrile, and dioxane, and found that the above equation is still useful. By comparing the correlations obtained, it was confirmed that the parameter SHA could be universally utilized for representing the difference in H-bonding effects involved in different partitioning systems.