Use of capillary electrophoresis with chemiluminescence detection for sensitive determination of homocysteine

A sensitive capillary electrophoresis (CE) method with chemiluminescence (CL) detection was developed for the determination of homocysteine (HCys) in human plasma. In this work, N-(4-aminobutyl)-N-ethylisoluminol was used as tagging reagent to label the analyte for achieving high assay sensitivity. N-(4-Aminobutyl)-N-ethylisoluminol-tagged HCys after CE separation reacted with hydrogen peroxide in the presence of horseradish peroxidase, producing CL emission. Experimental conditions for labeling analyte, CE separation, and CL detection were studied. The CL intensity was proportional to the concentration of HCys in the range of 2.5×10−8 to 5.0×10−6 M. Detection limit (S/N=3) was 7.6×10−9 M. Human plasma samples from healthy donors were analyzed by the presented method. HCys levels were found to be in the range of 9.50–15.3 μM.