Liposome electrokinetic chromatography (LEKC) is a good model evaluating the interaction of a drug with a biomembrane. Partition coefficients of neutral aromatic solutes in LEKC between 288～323 K were measured. A series of thermodynamic parameters were obtained by third-order polynomial fitting Van't Hoff plots. The thermodynamic partitioning behavior of those solutes was investigated. The results showed that the partition coefficient became greater with the increment of temperature and the number of CH₂ functional groups on benzenering. During the whole experiment temperature range (288～323 K), ΔH and TΔS were positive while ΔG was negative, which indicated that the partitioning process of solutes in LEKC system was entropy-driven. From 288 to 298 K, ΔC_p was negative and the LEKC partitioning system exhibited typical hydrophobic effect. From 303 to 323 K, ΔC_p was positive and the LEKC partitioning system betrayed a typical hydrophobic effect. A linear relationship between ΔH and ΔS indicated the occurrence of enthalpy-entropy compensation in the LEKC system.

Key words: neutral aromatic solute, liposome electrokinetic chromatography, thermodynamics, entropy-driven, hydrophobic interaction