The stacking boundary in capillary electrophoresis

The stacking boundary (SB) in capillary electrophoresis (CE) is elucidated. The SE is different from the electrolyte boundaries; for example, the comp osition of the SE changes with time while the composition of the electrolyt e boundaries ideally does not change with time. All these boundaries origin ate from an original concentration boundary found between the sample soluti on and background solution zones before application of voltage. The differe nces in electrophoretic mobilities cause them to separate from each other, as verified from the enhanced field Vacancy CE experiments and a special ex periment. Theoretical and some experimental studies on the fate of analyte zones in vacancy and differential CE are presented. Some equations are deri ved that provide insight into the behavior of analyte zones in enhanced fie ld vacancy CE. Furthermore, it was found that the composition and especiall y the conductivity of the sample solution in vacancy and differential CE ex periments are crucial in maintaining reproducibility of data and reliabilit y for qualitative and quantitative analysis. (C) 1999 John Wiley & Sons, In c.