A novel approach for a non competitive capillary electrophoresis immunoassay with laser-induced fluorescence detection for the determination of human serum albumin

A new non competitive capillary electrophoresis immunoassay format based on a separation into a capillary modified by analyte immobilisation is described. The injection of an excess of labelled antibody off-line preincubated with the analyte allows the surface capture of the free antibody and the immunocomplex detection. It was developed using the human serum albumin (HSA) as analyte, two FITC-labelled antibodies and a HSA covalently linked capillary. Two calibration curves with good run-to-run reproducibility and LOD – respectively 14.0 nM for the FITC-polyclonal antibody and 9.0 nM for the FITC-monoclonal antibody – were achieved. The assay was applied to HSA determination in spiked samples of human urine with acceptable recoveries.