Direct Detection of Biomolecules in a Capillary Electrophoresis-Chemiluminescence Detection System - Analytical Methods & Tools for Lyophilization

Direct Detection of Biomolecules in a Capillary Electrophoresis-Chemiluminescence Detection System
Received for review October 1, 2003. Accepted April 20, 2004.
Web Release Date: June 30, 2004
Kazuhiko Tsukagoshi,* Koji Nakahama, and Riichiro Nakajima
Anal. Chem.
ACS Publications
Copyright © 2006 American Chemical Society
Department of Chemical Engineering and Materials Science, Faculty of Engineering,Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
Abstract:
Direct detection of biomolecules, such as -amino acids, peptides, and proteins, was accomplished using a capillary electrophoresis-chemiluminescence detection system, in which a luminol-hydrogen peroxide-Cu(II)-catalyzed chemiluminescence reaction was utilized. Biomolecules migrated in the capillary, where they mixed with luminol and the Cu(II) catalyst included in the running buffer. The capillary outlet was inserted into a batch-type chemiluminescence detection cell with hydrogen peroxide-supplemented electrolyte solution. Chemiluminescence was observed at the tip of the capillary outlet. The chemiluminescence peak from biomolecules appeared due to the enhancement of Cu(II) catalytic activity for luminol-hydrogen peroxide chemiluminescence. The Cu(II) was more catalytically active when it interacted with biomolecules forming Cu(II)-biomolecule complexes. In this study, biomolecules were directly separated and detected in a capillary electrophoresis-chemiluminescence detection system. Twenty -amino acids, 4 peptides, and 11 proteins were examined. Most of them were detected with satisfactory CL intensity response. Glutamic acid, an -amino acid, was detected at concentrations ranging from 2.0 ? 10-7 to 1.2 ? 10-5 M with a detection limit (S/N = 3) of 1.0 ? 10-7 M (0.6 fmol). Glycylglycine, a peptide, was detected at concentrations ranging from 1.7 ? 10-7 to 1.2 ? 10-5 M with a detection limit (S/N = 3) of 1.7 ? 10-7 M (0.9 fmol). Hemoglobin, a heme protein, in which the heme structure was independently catalytically active, was detected at concentrations ranging from 1.2 ? 10-7 to 1.0 ? 10-5 M with a detection limit (S/N = 3) of 1.2 ? 10-7 M (0.6 fmol). Representative mixtures of -amino acids and peptides were well detected with superior separation.
You can view the abstract online. A subscription is required to view the full text or it can be purchased online.