ANALYTE FOCUSING IN CAPILLARY ELECTROPHORESIS USING ONLINE ISOTACHOPHORESIS

The on-line coupling of isotachophoresis with capillary electrophoresis as presented earlier was improved with respect to recovery, reproducibility and ease of operation by developing a new system. Owing to the isotachophoretic sample pretreatment resulting in analyte focusing, the corresponding determination limits in capillary electrophoresis could be enhanced by three orders of magnitude. It is shown that both the reproducibility and selectivity are improved considerably owing to the two-dimensional electrophoretic approach. The potential of one-line coupled isotachophoresis-electrophoresis was demonstrated using a fluorescein isothiocyanate derivative of the peptide angiotensin III as test compound.