Flow injection chemiluminescent immunoassay with para-phenylphenol and sodium tetraphenylborate as synergistic enhancers

A new approach of flow injection chemiluminescent immunoassay (FICLIA) with synergistic enhancement was developed. The synergistic action was significant in the chemiluminescence (CL) system of luminol-H₂O₂-HRP with two enhancers, para-phenylphenol (PPP) and sodium tetraphenylborate (NaTPB). The relative CL intensity was 128.84% stronger (compared to NaTPB alone) and 122.66% stronger (compared to PPP alone) using both enhancers than any one alone (both P<0.001). While the present approach was applied to the determination of rabbit IgG as a model analyte, satisfactory results were obtained in the dynamic range of 2-60 μg l⁻¹ with a detection limit of 0.68 fmol per injection and a precision of 4.7-9.3%, and the recoveries were 92.5-99.4%. The results of rabbit IgG determination accorded with those of radio immunoassay (RIA). The lifetime of the immuno-column was considerably long: one column was applied to more than 200 determinations in 1 month without significant loss of activity.