Capillary zone electrophoresis of dilute samples with isotachophoretic preconcentration

Abstract

Abstract A method for concentrating dilute samples prior to separation by capillary zone electrophoresis (CZE) is described. The principles of isotachophoresis are used to achieve higher local concentrations of the sample solution within a preconcentration capillary that is attached directly to the CZE separation capillary. Through a judicious choice of leading, terminating, and background electrolytes, the isotachophoretic preconcentration step can be performed on‐line with the CZE separation using common CZE instrumentation. The use of isotachophoretic preconcentration allows larger volumes of dilute sample solutions to be analyzed effectively in the zone electrophoretic mode, thereby reducing the stringent CZE requirements of small sample volumes and concentrated sample solutions.