[Study on factors affecting reproducibility of migration time in capillary electrophoresis]

The effects of running buffer on reproducibility of the migration time in the modes of capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MECC) were investigated. The parameters include concentration, pH value and the properties change of the running buffer. The results showed that the reproducibility of migration times may be improved through three approaches. First, the correlation between running buffer concentration and migration time was established and the running buffer concentration was determined by conductivities in order to improve the reproducibility. Second, it was found that the residual running buffer in the capillary showed significant influence on the repeatability of migration times. Thus, appropriate running or washing procedure between separations is necessary. Finally, the inlet reservior buffer plays an extremely important role in affecting the migration behaviors of solutes. Through improving the test apparatus, reproducible migration time was achieved as a result of increasing the frequency of replacing the buffer in the inlet reservior.