Analytical and micropreparative separation of peptides by capillary zone electrophoresis using discontinuous buffer systems.

The tiny injection volumes that are usually necessary to maintain the high efficiency of capillary zone electrophoresis present a major problem if only limited sample amounts are available. To increase the sample load, discontinuous buffer systems were developed that allow the on-column concentration of dilute samples. Injection volumes can be increased in this way by at least a factor of 30. These stacking systems were applied to the analysis of tryptic peptides, to the purity checking of high-performance liquid chromatographic fractions and for the micropreparative separation of peptides with subsequent amino acid sequence analysis.