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 achievc 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.

Recent methodological advances in the analysis of nitrite in the human circulation: Nitrite as a biochemical parameter of the l-arginine/NO pathway

“…column. An increase in sensitivity usually is obtained through improvement of the detector [70,71,[79][80][81].…”

“…However, the detection sensitivity needs to be improved. Strategies to improve the detection limit in CZE have been described and include: injection of low-conductivity sample matrices in which the diluted sample components are preconcentrated during the stacking across the stationary concentration boundary between the sample and the background electrolyte [65][66][67], use of an on-line packed precolumn [68], variation of pH [69][70][71], removal of chloride from the sample matrix (either by solid-phase extraction or reversed pre-electrophoresis) [72], and the use of on-line coupled column isotachophoresis-CZE [66,70,71].…”

Mathematical modeling of field-amplified sample injection in high-performance capillary electrophoresis

“…Several techniques have been reported to perform on-column concentration to enhance the detectability in HPCE. (4,5). However, a careful choice of leading, terminating, and background electrolytes is required to perform this isotachophoretic preconcentration step.…”

Electrophoretic sample stacking

“…This method was introduced by Dolník et al . 27. As everything must be done in one capillary, elaborate operation must be applied.…”