Sample stacking in capillary zone electrophoresis: Principles, advantages and limitations

Abstract

The principles of stacking procedures are described and their properties are discussed, including the fundamentals of the behavior of zone boundaries and the consequences of the self-correcting properties of boundaries in moving boundary electrophoresis, isotachophoresis, and zone electrophoresis. Further, the diverse possibilities of stacking procedures and the unavoidable destacking are described, and several examples of practically applied stacking procedures are given, besides many references to applications. Some limitations in the use of stacking procedures are discussed. The paper is arranged in such a way that it can serve both as an introduction into the field and as a reference overview.

Dynamic computer simulations of electrophoresis: A versatile research and teaching tool

“…Dynamic simulation led to a detailed description of many types of steady-state and non-steady-state (i.e. progressively broadening) electrophoretic boundaries that are produced between strong and weak electrolytes upon current flow [2,3,46,64,126,127,139] (for examples see Figs. 4-6 and 8-12), was used to discover and understand new types of migrating boundaries [140][141][142][143], provided insight into the regulation principles associated with current flow [2,3,46,123,124,127,144] , which is a strong acid with a mobility equal to that of the buffer additive and which was sampled together with the neutral analytes.…”

“…ITP is one of the oldest electrophoretic separation techniques and as such there have been a number of simulations on ITP and the behavior of the boundaries, although many of these have been used for the verification of the simulation software and for educational purposes [2][3][4]64]. In one of the first non-trivial studies on ITP boundaries, Mosher et al…”

“…MBE configurations, i.e. systems with multiple components of like charge in either or both of the two buffers forming a discontinuity, were studied by dynamic simulation in a number of laboratories [3,23,36,43,60,61,64,161,162]. Most of these produce zones with constant concentration and of gradually increasing length.…”

“…In the case of components with higher mobilities than the leading constituent, penetration of the faster migrating compound into the leading zone occurs [162]. Examples investigated were those associated with classical MBE [3,23,43,61,64], ITP systems in which the leading electrolyte, the terminating electrolyte or both electrolytes contain another common component (ionic admixture, e.g. a difficult to remove impurity) [36,161], and SDS electrophoresis [3,60].…”

Integration of various stacking processes in carrier ampholyte-based capillary electrophoresis

“…In dynamic pH junction, pH differences along the separation path are used to enhance the sensitivity. These methods have been well described in recent review articles [15][16][17][18]. When used individually, sensitivity enhancement factors (SEFs) ranging from few tens to few thousands can be achieved.…”