Hydrogen bonding. 38. Effect of solute structure and mobile phase composition on reversed‐phase high‐performance liquid chromatographic capacity factors

Reversed‐phase HPLC capacity factors, as log k ′, have been correlated through the LFER equation:\documentclass{article}\pagestyle{empty}\begin{document}$${\rm log k}^\prime = {\rm c} + {\rm rR}_2 + {\rm s\pi }_2^{\rm H} + {\rm a}\sum {\rm \beta }_2^0 + {\rm vV}_{\rm X}$$\end{document} where k ′ is the capacity factor for a series of solutes in a given stationary phase–mobile phase system, and the explanatory variables are the solute descriptors: R 2 an excess molar refraction, π   2 Hthe dipolarity/polarizability, Σα   2 Hthe overall hydrogen‐bond acidity, Σβ   2 0the overall hydrogen‐bond basicity and V x the McGowan volume. This equation was applied to various C 18 stationary phases with methanol–water, acetonitrile–water and tetrahydrofuran–water buffered mobile phases. The solute and mobile phase factors that influence log k ′ values are set out, and a comparison is made between log k ′ values and water–octanol partition coefficients.