Thermodynamic behaviour in capillary electrochromatography

Eindhoven University of Technology, Department of Chemical Engineering and Chemistry, Laboratory of Instrumental Analysis, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; Fax: +31 40 245 3762
Journal of Separation Science (Impact Factor: 2.59). 06/2002; 25(9):569 - 576. DOI: 10.1002/1615-9314(20020601)25:9<569::AID-JSSC569>3.0.CO;2-3

ABSTRACT The thermodynamic behaviour of solutes was examined on four reversed-phase (RP) stationary phases under pressure-driven (viz. high performance liquid chromatography, HPLC) and electro-driven (viz. capillary electrochromatography, CEC) conditions. Thermodynamic constants such as standard enthalpy, entropy, and Gibbs free energy were compared for both separation modes. Differences and/or similarities observed were used as a tool in gaining a better understanding of the separation mechanism in CEC compared to HPLC. In addition, effects of temperature on the magnitude of electroosmotic flow (EOF) are explained in detail.