Sample self-stacking and sample stacking in zone electrophoresis with major sample components of like charge: general model and scheme of possible modes.
A theoretical study is presented of zone electrophoretic behavior of samples that contain one or more minor analytes and at least one major ionogenic component of like charge. Based on a simple model comprising weak univalent anionic electrolytes, conditions are derived under which analytes are temporarily focused isotachophoretically into very narrow zones by a sample self-stacking effect provided by the major sample components. Requirements for minimal/maximal mobility and a background coion concentration dependent minimal concentration of a major sample component (stacker) are presented. For systems in which sample self-stacking does not apply, an expression for the concentrating factor is derived that involves the effects of both nonselective (classical) and selective sample stacking, the latter being a consequence of electrophoretic separation of the minor analyte from the major component. The theory derived is discussed with selected model examples by using both numerical calculation and computer simulation.
Gebauer
P
P
Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Brno.
Thormann
W
W
Bocek
P
P
D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods*; D008432:Mathematical Computing; D008958:Models, Molecular