Noncompetitive capillary electrophoresis based immunoassay for proteins with laser induced fluorescence detection

The noncompetitive capillary electrophoresis based immunoassay for proteins using bovine serum albumin (BSA) and its monoclonal antibody (anti-BSA) as a model system were studied. BSA was labeled with fluorescein isothiocyanate and used as a tracer to determine anti-BSA. The binding reaction between anti-BSA and the tracer reached equilibrium in less than 20 minutes, and separation between the immunocomplexes and the free tracer was achieved in 12 minutes using capillary zone electrophoresis. The linear dynamic range of the standard curve was 8 similar to 150 nmol/L, and the detection limit was 5 nmol/L when a tracer concentration of 320 nmol/L was used. Influences of separation conditions such as buffer concentration, pH and separation voltage was also studied.