Potential of on-line isotachophoresis-capillary zone electrophoresis with hydrodynamic counterflow in the analysis of various basic proteins and recombinant human interleukin-3.

Isotachophoresis-capillary zone electrophoresis with hydrodynamic counterflow was applied to the analysis of various basic model proteins and recombinant human interleukin-3. The use of coated capillaries and simple modifications of a commercial capillary zone electrophoresis (CZE) system allowed the detection of concentrations in the 10(-8) M region. The limit of detection was decreased by a factor of 100 compared to conventional CZE. The separation efficiency was unaffected by the preceding isotachophoretic step. Our method is applicable to the analysis of proteins with an isoelectric point higher than 7.0.