Investigation of Adsorption Thermodynamics at Electrified Liquid-Solid Interfaces by Electrochemically Modulated Liquid Chromatography

A method to investigate electrosorption thermodynamics has been developed by examination of the temperature dependence of solute retention by means of electrochemically modulated liquid chromatography (EMLC). This hybrid technique couples electrochemistry and liquid chromatography, which enables the manipulation of solute retention through changes in the potential applied (Eapp) to a conductive stationary phase like glassy carbon, porous graphitic carbon, and boron-doped diamond. An understanding of the thermodynamics of the EMLC separation mechanism would further interpretations of the rules to predict retention, which may also provide fundamental insights into sorption processes and the structure of the electrical double layer of importance to a number of other technologies (e.g., battery and fuel cells). This paper describes a study in which the dependence of retention for two naphthalene disulfonates (1,5- and 2,6-naphthalene disulfonate) was measured at different fixed values of Eapp [-200 to +200 mV...