HPLC-Based Method for Estimating the Temperature Dependence ofn-Octanol−Water Partition Coefficients

Retention time measurements on reversed phase HPLC-columns over a 50 K temperature range are used to estimate the enthalpy of octanol−water phase transfer Δ OW H for 38 organic compounds of environmental relevance, including selected chlorinated benzenes (CBzs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated naphthalenes (PCNs) and biphenyls (PCBs). Literature K OW values as a function of temperature for CBzs served as a reference. Δ OW H for these compounds range from 13 to 32 kJ/mol, confirming a relatively minor temperature dependence of their partitioning between water and octanol. For the chlorinated aromatics a strong linear relationship between Δ OW H and molar volume was observed. The temperature-dependent retention volumes are also used to estimate K OW of selected PCNs and PAHs at 25 °C.