ISOTACHOPHORESIS WITH 2 LEADING IONS AND MIGRATION BEHAVIOR IN CAPILLARY ZONE ELECTROPHORESIS .1. ISOTACHOPHORESIS WITH 2 LEADING IONS

A mathematical model for isotachophoresis with two leading ions is presented and, based on this model, computer programs are set up for the calculation of the parameters of the different zones. With this model it is possible to calculate at what level a second leading ion may be present, e.g., carbonate ions in the separation of anions at a high pH, without disturbing the isotachophoretic separation. Calculated values of the specific zone resistance and response values are compared with values experimentally obtained showing good agreement. Calculations with this model show that with the presence of a second leading ion the zone lengths elongate (higher values of the response factor) and at a certain concentration ratio of the two leading ions, also dependent on the effective mobilities of the ions, the isotachophoretic condition is lost and isotachophoresis changes into zone electrophoresis. © 1990.