Flow immunoassay for detection of human chorionic gonadotrophin using a cation exchange resin packed capillary column

A human chorionic gonadotrophin (HCG) detection was carried out by the flow immunoassay system with a cation exchange resin packed capillary column (762µm i.d.×10cm length), that can be considered a miniaturised version of the previously reported system. The HCG and fluorescein isothiocyanate (FITC) conjugated immunoglobulin G (IgG) antibody complex was separated from free FITC conjugated IgG on the basis of differences in isoelectric points. The fluorescence intensity correlated linearly with concentrations of HCG in the range of 251500mIU/ml. This simple technique permits the assay of HCG within 1.3min. It was possible to reuse of free FITC conjugated IgG. This simple and rapid immunoassay method can be used for the continuous detection of HCG.