Bidirectional analytical isotachophoresis: Simultaneous determination of anionic and cationic boundaries

This paper deals with electrolyte systems capable of producing suitable isotachophoretic zone structures in either migration direction. These systems contain moving reaction boundaries. A dilute solution of a strong acid as anolyte and the sodium salt of a weak acid as catholyte are analyzed to provide insight into the features of such dual systems. For various electrolyte arrangements the boundaries are examined for resolving capability in isotachophoresis. Both anionic and cationic boundaries were followed simultaneously using a capillary type apparatus with an array detector.