New option in capillary zone electrophoresis: Use of a transient ionic matrix (dynamic pulse)

Abstract

A method which allows the separation possibilities of capillary zone electrophoresis and zone electrophoresis to be improved and extended is described. The analyte, injected into the primary electolyte and migrating from the injection point to the detector, passes during this migration through the zone of a transient ionic matrix which separates selectively some of the components, and before detection (the analyte) returns to the primary electrolyte. The zone of the transient ionic matrix also migrates through the separation column (in the demonstrated cases in the direction from the detector to the sampling point) and both its composition and effective time can easily be changed in order to attain complete separation of all components as well as the minimum separation time. The transient ionic matrix may be advantageously formed by solvolytic (H +, OH −) and/or complex forming ions. This method extends the working p K a of weak acids or bases separated in one analysis, i.e., it enables single stage analyses which are not normally realizable. The advantages of the method are its speed, its suitability for automation and its perfect quantitative interpretation of the record (detection always proceeds in the original background electrolyte). It is in principle also possible to use more than one type of transient ionic matrix in a single analysis.