Influence of the Modifier Type and its Concentration on Electroosmotic Flow of the Mobile Phase in Pressurized Planar Electrochromatography

Aneta Hałka-Grysińska; Paweł W Płocharz; Andrzej Torbicz; Ewa Skwarek; Władysław Janusz; Tadeusz H Dzido

doi:10.1007/s10337-014-2689-6

Influence of the Modifier Type and its Concentration on Electroosmotic Flow of the Mobile Phase in Pressurized Planar Electrochromatography

Chromatographia. 2014;77(13):941-950. doi: 10.1007/s10337-014-2689-6. Epub 2014 Jun 1.

Authors

Aneta Hałka-Grysińska¹, Paweł W Płocharz², Andrzej Torbicz¹, Ewa Skwarek³, Władysław Janusz³, Tadeusz H Dzido¹

Affiliations

¹ Department of Physical Chemistry, Medical University of Lublin, Lublin, Poland.
² Department of Cosmetology, Faculty of Physical Education and Sport in Biala Podlaska, Jozef Pilsudski University of Physical Education in Warsaw, Biala Podlaska, Poland.
³ Department of Radiochemistry and Colloid Chemistry, Maria Curie-Skłodowska University, Lublin, Poland.

Abstract

The aim of this work was to find a relationship between electroosmotic flow (EOF) velocity of the mobile phase in pressurized planar electrochromatography (PPEC) and physicochemical properties like zeta potential, dielectric constant, and viscosity of the mobile phase as well as its composition. The study included different types of organic modifiers (acetonitrile, methanol, ethanol, acetone, formamide, N-methylformamide and N,N-dimethylformamide) in the full concentration range. In all experiments, chromatographic glass plates HPTLC RP-18 W from Merck (Darmstadt) were used as a stationary phase. During the study we found that there is no linear correlation between EOF velocity of the mobile phase and single variables such as zeta potential or dielectric constant or viscosity. However, there is quite strong linear correlation between EOF velocity of the mobile phase and variable obtained by multiplying zeta potential of the stationary phase-mobile phase interface, by dielectric constant of the mobile phase solution and dividing by viscosity of the mobile phase. Therefore, it could be concluded that the PPEC system fulfilled the Helmholtz-Smoluchowski equation.

Keywords: Dielectric constant; Electroosmotic flow velocity; Organic modifier; Pressurized planar electrochromatography (PPEC); Viscosity of the mobile phase; Zeta potential.