The binding constant( K b) between fluorescein isothiocyanate labeled bovine serum albumin(FITC BSA) and its monoclonal antibody was determined using the ligand separation mode of affinity capillary electrophoresis(ACE) with laser induced fluorescence detection(LIF). Free FITC BSA and the complexes were separated by capillary electrophoresis in 7 min after incubation. The running buffer was 100 mmol/L HEPES at pH 7 4, and separation voltage was 30 kV. The K b was determined to be 4 7×10 8 L/mol using Scatchard plotting method. The influences of incubation time and electrophoresis conditions on determination were also studied.
