On-line electrodialysis capillary zone electrophoresis of adenosine triphosphate and inositol phosphates

Electrodialysis (ED) has been coupled to capillary zone electrophoresis (CZE) as an on-line sample pretreatment technique. Analytes are introduced into the fused-silica capillary through a membrane with a molecular mass cut-off of 30 000. As reversed polarity is applied only small negatively charged ions are injected whereas positively charged and/or large compounds are retained. ED takes only ca. 20 s and is comparable with electrokinetic injection in several respects. ED-CZE has been applied to adenosine triphosphate in blood plasma and to inositol phosphates in fermentation broth.