ANALYSIS OF A DILUTE SAMPLE BY CAPILLARY ZONE ELECTROPHORESIS WITH ISOTACHOPHORETIC PRECONCENTRATION

A capillary zone electrophoresis (CZE) apparatus utilizing on-line isotachophoretic (ITP) preseparation was constructed and it was shown that the dependence of the migration time in CZE on sample concentration was avoided by ITP preconcentration. The concentration and volume of the test mixture injected by using a microsyringe were in the range of 166-1.66 muM and 0.5-50 mul, respectively. The ratio of the sample volume to the separation column volume (27 mul) was in the range 1.9-185%. Although the migration time in the CZE stage did not change when ITP preconcentration was utilized, if the latter was not used the migration time was prolonged up to 400% non-linearly to the above ratio. The utility of ITP-CZE for the determination of trace components in a matrix was also demonstrated.