The use of metalion-supplemented buffers to enhance the resolution of peptides in capillary zone electrophoresis

Abstract

The potential of metal ion-containing buffers to enhance the resolution of peptides in capillary zone electrophoresis was evaluted. The impact of adding Cu(II) and Zn(II) salts to electrophoresis buffers is shown to affect the migrational behavior of several dipeptides containing histidine. Interaction with a metal ion differentially decreases the electrophoretic mobilities of peptides which comigrate in the absence of metal ions, thus causing their separation. This effect is obtained at low pH where the large net charge on the samples yields short analysis times. The dependence of the resolution on Zn(II) concentration is presented for two different samples. The influence of the background buffer is discussed.