POSTCOLUMN DERIVATIZATION OF PEPTIDE WITH FLUORESCAMINE IN CAPILLARY-ELECTROPHORESIS

Fluorescamine is used as a postcolumn derivatization reagent for fluor escence detection of peptides after separation by capillary electropho resis. The problems resulting from the use of an organic solvent have been solved by introducing LiClO4 and 5% water into the postcolumn der ivatization reagent. The reaction rate and detection sensitivity of am ino acids and small peptides observed with fluorescamine and OPA were compared. Fluorescamine gives much higher sensitivity than o-phthaldia ldehyde (OPA) for small peptides, with detection limits for the select ed peptides and amino acids below 0.1 mu mol l(-1). Under optimized ex perimental conditions, the method has a good reproducibility and separ ation efficiency for peptides. The method was applied for the analysis of the protein tryptic digests. Only submicromolar concentrations of proteins were required. (C) 1998 Elsevier Science B.V. All rights rese rved.