Direct analysis of peptides and amino acids from capillary electrophoresis

Capillary zone electrophoresis of peptides on a preparative scale and direct analysis of both amino acid sequences and compositions are demonstrated. Using native and synthetic peptides prepared by repetitive runs and appropriate collections, sufficient material for direct sequence analysis is obtained after just a few runs, while single runs suffice for total compositions. Electrophoretic direct amino acid analysis without derivatization is also possible and gives especially high sensitivity for aromatic residues (less than 200 fmols) plus convenient distinction of amidated versus free C-terminal residues after carboxypeptidase digestions.