The influence of electric fields on surface interactions in adsorption TLC. Part I

Electrochromatography (ETLC) is one of the newest chromatographic methods. The influence of electric fields an a chromatographic system, in particular the adsorbents SiO2 and Al2O3 is demonstrated. One property characterizing chromatographic adsorption systems is the surface free energy. A thin laye r nicking technique was used to determine the solid surface free energy com ponents fur Merck precoated silica and alumina plates. The approach of Van Oss et al. and the Washborn equation were used to determine the surface fre e energy component for silica and alumina. The surface free energy of these solids depends on the strength of the electric field and on the direction of the lines of the electric field. These phenomena affect chromatographic measurements, and the speed of migration of mobile phases.