Competitive immunoassay using protein G affinity capillary chromatography with laser induced fluorescence detection

A simple approach to perform competitive immunoassay using protein G affini ty capillary chromatography and laser induced fluorescence (LIF) detection was described. Bovine serum albumin (BSA) was used as a model to test the p erformance of the system. The assay used fluorescein isothiocyanate (FITC) labeled BSA as a tracer and an anti-BSA monoclonal antibody as the immunore agent. Capillaries with inner diameter of 150 mu m were packed with recombi nant protein G bound perfusive support and used to capture the immunocomple xes, which were subsequently desorbed by 100 mM glycine (pH 9.0) and then d etected using LIF. The results demonstrated the feasibility to perform comp etitive immunoassay using this system with high sensitivity and small sampl e size.