Solute-solvent interactions in chemistry and biology. Part 7. An analysis of mobile phase effects on high pressure liquid chromatography capacity factors and relationships of the latter with octanol-water partition coefficients

log k† values on a C₁₈ stationary phase with 90/10, 75/25, 60/40, 45/55 and 30/70 methanol-water mobile phases are correlated in terms of the generalized linear solvation energy relationship, log k' = XYZ_o + mV₁/100 + sπ* + bβ_m + aα_m where V₁ is the intrinsic (van der Waals) molar volume, and π*, β_m, and α_m are the solvatochromic parameters that measure solute dipolarity-polarizability, hydrogen-bond acceptor basicity, and hydrogen-bond donor acidity. The correlation equations are combined with the corresponding equation for octanol-water partition coefficients to generate new equations that demonstrate the exact relationships between the various log k's and log K_ow.